Free online calculators checked against published sources
Free, fast, source-cited calculators that work without JavaScript. Every result is a shareable link, every formula is tested against a published authority.
Construction · 8 calculators
Concrete Calculator
Concrete Calculator returns required concrete volume from length, width, and depth in matching units.
Square Footage Calculator
Square Footage Calculator returns floor area from entered length and width measurements.
Roofing Calculator
Roofing Calculator estimates roof area from entered length, width, and slope factor.
Tile Calculator
Tile Calculator derives tiles from length, width, tile length, and tile width.
Stair Calculator
Stair Calculator returns required whole steps from total rise and selected rise per step.
Mulch Calculator
Mulch Calculator estimates material volume from bed length, width, and desired application depth.
Gravel Calculator
Gravel Calculator estimates material weight from area dimensions, depth, and selected gravel density.
ADU Cost Calculator
ADU Cost Calculator estimates project cost from floor area and cost per square foot.
Date & Time · 9 calculators
Date Calculator
Count the days between two dates, with business days, weeks, and a years-months-days breakdown that lands exactly on your end date. Leap years handled.
Age Calculator
Calculate age in completed years, months and days for any explicit comparison date, with exact elapsed days and the next birthday shown.
Time Calculator
Time Calculator combines entered hours and minutes into a total minute value.
Hours Calculator
Hours Calculator converts an entered minute total into decimal hours for time comparison.
Time Card Calculator
Time Card Calculator returns worked hours from clock-in and clock-out times for one shift.
Time Duration Calculator
Time Duration Calculator returns elapsed hours from entered start and end times.
Time Zone Calculator
Time Zone Calculator shifts an entered hour by the selected UTC offset.
Day Counter
Day Counter returns the calendar-day difference between entered start and end day numbers.
Day of the Week Calculator
Day of the Week Calculator maps an entered day number to its weekday index.
Financial · 74 calculators
Loans & Mortgages
Mortgage Calculator
Work out your monthly mortgage payment with taxes, insurance, PMI and HOA, then see the full amortization schedule and what the loan really costs.
FHA Loan Calculator
Estimate your FHA loan payment with upfront and annual MIP, taxes, insurance and HOA, using HUD’s own mortgage insurance rate table and cancellation rules.
VA Mortgage Calculator
Calculate your VA loan monthly payment with accurate funding fees, interest costs, and amortization based on current rates and loan terms.
APR Calculator
Calculate the APR on a loan including fees, and see how far the annual percentage rate sits above the note rate you were quoted.
Personal Loan Calculator
Work out the monthly payment, total interest and payoff timeline on a fixed-rate personal loan, and see what paying a little extra each month would save you.
Auto Loan Calculator
Work out a car payment the way a dealer does — sales tax, title and fees financed, trade-in and negative equity included, with the total interest shown.
Amortization Calculator
Build a dated amortization schedule for any fixed-rate loan, split every payment into principal and interest, and see how extra payments change payoff.
Student Loan Calculator
Estimate a fixed student loan payment, total interest and payoff time, then see how extra monthly principal could reduce the cost.
Mortgage Payoff Calculator
Compare your current mortgage payoff with extra monthly principal or an immediate lump sum, and see the payoff date, interest, and time saved.
Refinance Calculator
Compare a fixed-rate mortgage refinance with your current payment, including closing costs, break-even timing, five-year cost, and lifetime savings.
House Affordability Calculator
See how much house you can afford from your income, debts and down payment using the 28/36 front-end and back-end ratios, with a full monthly breakdown.
HELOC Calculator
Size your home equity line of credit, then see the interest-only draw payment, the amortizing repayment payment, and the payment shock between them.
Home Equity Loan Calculator
Work out your home equity loan payment, how much you can borrow at your lender’s combined loan-to-value cap, total interest, and both loans together.
Debt Payoff Calculator
See how extra monthly payments change your debt payoff time, total interest, and balance using a cent-rounded repayment schedule you can compare.
Debt Consolidation Calculator
Estimate the payment, interest, and fee-inclusive cost of replacing several balances with one fixed-rate consolidation loan before accepting terms.
Credit Card Payoff Calculator
Estimate how long a credit-card balance takes to repay, total interest, and how extra monthly payments change the payoff plan under fixed terms.
Business Loan Calculator
Estimate a business loan payment, total interest, and fee-inclusive borrowing cost for a fixed-rate financing scenario before lender terms are finalized.
Auto Lease Calculator
Estimate a vehicle lease payment, depreciation, and total scheduled cost from negotiated price, residual value, rate, term, and upfront reduction.
Debt-to-Income Calculator
Calculate debt-to-income ratio from gross monthly income and recurring monthly debt payments to screen borrowing capacity with clear assumptions.
Down Payment Calculator
Estimate the cash down payment, resulting mortgage amount, and principal-and-interest payment from home price and financing assumptions.
Mortgage Recast Calculator
Mortgage Recast Calculator returns a simplified monthly payment from remaining balance and months left.
Taxes
Income Tax Calculator
Work out your 2026 federal income tax from the official IRS brackets, see your marginal and effective rate, and exactly what each tax bracket cost you.
Salary Calculator
Convert pay between hourly, daily, weekly, biweekly, semimonthly, monthly and annual using the FLSA conversion, and see what an hour actually worked is worth.
Capital Gains Calculator
Estimate 2026 federal tax on a short- or long-term capital gain using sale proceeds, adjusted basis, filing status, and taxable income.
Take-Home Pay Calculator
Estimate annual and monthly take-home pay from gross pay, pre-tax deductions, and effective federal, state, and payroll rates for budgeting.
Estate Tax Calculator
Estimate a simplified taxable estate and scenario tax after deductions and an entered exemption, with IRS references and clear limitations.
Marriage Tax Calculator
Compare a simplified joint and separate tax scenario from two incomes, a combined deduction, and an entered marginal rate.
Sales Tax Calculator
Calculate sales tax, discounted subtotal, and final purchase total from price, quantity, discount, and an entered tax rate.
VAT Calculator
Add value-added tax to a net price and show the VAT amount and gross price using a clear rate and jurisdiction-neutral formula.
Child Tax Credit Calculator
Child Tax Credit Calculator estimates scenario credit from children and credit per child.
Retirement
Annuity Calculator
Calculate the present value, payment amount, term, or interest rate of an ordinary annuity. Solve for any variable given the others in this annuity calculator.
Annuity Payout Calculator
Find the fixed payout a lump sum can pay over a set number of years, or how long a fixed payout will last, with a year-by-year balance depletion schedule.
IRA Calculator
Work out how much of your traditional IRA contribution is deductible, then compare traditional against Roth on what each actually leaves you after tax.
RMD Calculator
Work out your required minimum distribution from the IRS Uniform Lifetime Table, and project what you must withdraw from an IRA year by year from age 73.
Retirement Calculator
See what your savings reach by retirement, the nest egg your income goal really needs, and the monthly contribution that closes the gap. Inflation-adjusted.
401(k) Calculator
Project your 401(k) balance with salary growth, employee deferrals, employer matching, monthly compounding, and the official 2026 IRS limits.
Roth IRA Calculator
Estimate your 2025 or 2026 Roth IRA contribution limit from IRS income rules, then project the balance, contributions and tax-free growth over time.
Social Security Calculator
Compare Social Security retirement benefits from age 62 to 70 using official SSA reductions, delayed credits, full retirement age, and rounding rules.
Pension Calculator
Estimate a level monthly pension payout from a starting balance, assumed annual return, chosen payment period, and clear retirement planning assumptions.
RSU Vesting Calculator
RSU Vesting Calculator computes after-tax proceeds from shares, share price, and tax per share.
Investing
Compound Interest Calculator
See what regular saving really becomes: future value, total interest and the true APY for any rate, term and compounding frequency, year by year.
Interest Calculator
Work out the interest a lump sum earns, compare simple against compound, and see the APY that any quoted rate and compounding schedule really pays.
Interest Rate Calculator
Know the loan amount, the monthly payment and the term but not the rate? Solve for the interest rate you are really paying, using the Regulation Z method.
Finance Calculator
Solve any one of the five time-value-of-money variables — periods, rate, present value, payment or future value — from the other four, with signed cash flows.
CD Calculator
Estimate CD maturity value, total interest, APY, and the early-withdrawal penalty before you cash out before the term ends, using your deposit terms.
Savings Calculator
See how regular saving grows over time with a starting balance, recurring deposits, compound interest, and the account’s effective APY for planning.
Investment Calculator
Project an investment with monthly contributions, annual fees, and inflation. See growth, fee drag, and the ending value in today’s dollars.
Rent vs Buy Calculator
Compare renting with buying by net worth, including mortgage equity, closing and selling costs, upkeep, rent growth, and invested cash differences.
Depreciation Calculator
Calculate straight-line depreciation, monthly expense, and ending book value for an asset across its estimated useful life with clear assumptions.
Inflation Calculator
Estimate how inflation changes the future purchasing-power cost of an amount over time using a transparent annual scenario rate and horizon.
Rental Property Calculator
Estimate rental property cash flow after rent, operating expenses, and a modeled fixed-rate mortgage payment for a simple planning scenario.
Real Estate Calculator
Screen a real-estate scenario with price, financing, rent, operating costs, mortgage payment, and a transparent monthly cash-flow estimate.
IRR Calculator
Estimate the internal rate of return for an initial investment with equal annual cash flows and a terminal value using transparent assumptions.
ROI Calculator
Calculate return on investment after additional costs, showing net value, gain or loss, and the exact percentage formula used.
Simple Interest Calculator
Simple Interest Calculator projects balance from principal, annual rate, and elapsed years.
Future Value Calculator
Future Value Calculator returns a projected future value from principal, contribution, rate, years, and frequency.
Present Value Calculator
Present Value Calculator computes the present value of a future amount from future value, rate, and years.
Margin Calculator
Margin Calculator returns gross margin percentage from entered revenue and cost amounts.
Commission Calculator
Commission Calculator returns earned commission from an entered sales total and percentage rate.
Payback Period Calculator
Payback Period Calculator estimates years to recover an initial investment from annual cash flow.
Currency Calculator
Currency Calculator returns a converted amount from the entered amount and exchange rate.
GDP Calculator
GDP Calculator returns economic output from consumption, investment, government spending, and net exports.
Crypto Profit Calculator
Crypto Profit Calculator derives profit from sell price, buy price, and units.
Solar Payback Calculator
Solar Payback Calculator returns payback period from system cost and annual savings.
Everyday
Budget Calculator
Build a monthly budget from take-home income, pay frequency, and custom needs, wants, savings, and debt-allocation percentages for planning.
Discount Calculator
Find the savings, discounted sale price, and optional after-tax total from an original price and percentage discount.
Tip Calculator
Calculate a tip, total bill, and equal per-person share from the bill amount, gratuity rate, group size, and clear rounding assumptions.
Freelance Rate Calculator
Freelance Rate Calculator derives hourly rate from target income, expenses, and billable hours.
Hourly to Salary Calculator
Hourly to Salary Calculator finds annual salary from hourly, hours per week, and weeks.
Cost of Living Calculator
Cost of Living Calculator returns adjusted cost from current cost and index.
HSA/FSA Calculator
HSA/FSA Calculator returns remaining account balance from entered contributions and eligible expenses.
Break Even Calculator
Break Even Calculator determines break-even units from fixed costs, price, and variable cost.
Burn Rate Calculator
Burn Rate Calculator determines burn rate from starting cash, ending cash, and months.
Subscription Audit Calculator
Subscription Audit Calculator returns monthly subscription cost from monthly cost and subscriptions.
Health & Fitness · 33 calculators
BMI Calculator
Work out your body mass index from height and weight in either units, see which NHLBI category it falls in, and the healthy weight range for your height.
Calorie Calculator
Work out the calories you need each day from the Mifflin-St Jeor equation and FAO activity levels, with targets for losing or gaining weight at a chosen rate.
Body Fat Calculator
Body Fat Calculator derives body fat % from sex, waist measurement, neck measurement, and height.
TDEE Calculator
TDEE Calculator estimates daily energy expenditure from BMR and an entered activity factor.
Macro Calculator
Macro Calculator derives carbohydrate grams from calories, protein percentage, and fat percentage.
Pregnancy Calculator
Pregnancy Calculator estimates a due date from the last menstrual period and cycle length.
BMR Calculator
BMR Calculator estimates resting energy needs from sex, weight, height, and age.
Ideal Weight Calculator
Ideal Weight Calculator estimates Devine weight from sex and entered height measurements.
Healthy Weight Calculator
Healthy Weight Calculator returns a BMI-based weight range from an entered height.
Lean Body Mass Calculator
Lean Body Mass Calculator returns lean mass from weight and entered body-fat percentage.
Due Date Calculator
Due Date Calculator estimates a pregnancy due date from last menstrual period and cycle length.
Ovulation Calculator
Ovulation Calculator estimates an ovulation date from period start and typical cycle length.
Conception Calculator
Conception Calculator estimates a conception date from an entered pregnancy due date.
Period Calculator
Period Calculator computes next period day from last period day and cycle days.
Protein Calculator
Protein Calculator returns daily protein grams from body weight and selected grams-per-kilogram factor.
Carbohydrate Calculator
Carbohydrate Calculator returns daily carbohydrate grams from calorie intake and selected carbohydrate percentage.
Fat Intake Calculator
Fat Intake Calculator returns daily fat grams from calorie intake and selected fat percentage.
Water Intake Calculator
Water Intake Calculator determines water milliliters from weight and ml per kg.
Calories Burned Calculator
Calories Burned Calculator estimates energy used from body weight, exercise duration, and activity intensity.
One-Rep Max Calculator
One-Rep Max Calculator estimates maximum lift from entered weight and completed repetitions.
Target Heart Rate Calculator
Target Heart Rate Calculator returns target HR from age, resting heart rate, and intensity.
Pace Calculator
Pace Calculator returns minutes per distance unit from route length and elapsed time.
BAC Calculator
BAC Calculator estimates blood alcohol concentration from alcohol, weight, sex, and elapsed hours.
GFR Calculator
GFR Calculator computes an estimated filtration rate from creatinine, age, and sex.
Sleep Calculator
Sleep Calculator suggests a bedtime from wake time and desired sleep duration.
Body Surface Area Calculator
Body Surface Area Calculator estimates BSA from entered height and weight using Mosteller’s formula.
Army Body Fat Calculator
Army Body Fat Calculator estimates an Army body-fat percentage from sex, waist measurement, neck measurement, and height.
Body Type Calculator
Body Type Calculator returns a BMI-based body-size result from height and weight.
Pregnancy Weight Gain Calculator
Pregnancy Weight Gain Calculator estimates guideline gain from pre-pregnancy BMI and elapsed weeks.
Overweight Calculator
Overweight Calculator returns a BMI category from entered height and weight measurements.
Sleep Cycle Calculator
Sleep Cycle Calculator suggests bedtime from wake time and complete 90-minute cycles.
Running VDOT Calculator
Running VDOT Calculator returns a training pace estimate from race distance and elapsed minutes.
Macro Cycling Calculator
Macro Cycling Calculator returns a cycling-day calorie target from baseline calories and increase percentage.
Math · 43 calculators
Percentage Calculator
Calculate a percentage of a number, find what percentage one value is of another, or measure percentage change with exact decimal arithmetic.
Scientific Calculator
Evaluate sine, cosine, tangent, logarithms, square roots and powers with decimal-safe inputs, degree or radian angles, and cited formulas.
Standard Deviation Calculator
Standard Deviation Calculator returns sample variability from four observations around their arithmetic mean.
Statistics Calculator
Statistics Calculator returns the arithmetic mean from four entered sample values for comparison.
Probability Calculator
Probability Calculator returns a percentage from favorable outcomes and total possible outcomes.
Confidence Interval Calculator
Confidence Interval Calculator returns bounds from mean, standard deviation, sample size, and z-score.
Triangle Calculator
Triangle Calculator returns area from entered base and perpendicular height measurements in matching units.
Right Triangle Calculator
Right Triangle Calculator returns hypotenuse length from two perpendicular sides using the Pythagorean theorem.
Volume Calculator
Volume Calculator returns rectangular volume from entered length, width, and height measurements.
Surface Area Calculator
Surface Area Calculator returns rectangular-prism surface area from three entered dimension measurements.
Fraction Calculator
Fraction Calculator returns the exact sum of two fractions from their entered numerators and denominators.
Quadratic Formula Calculator
Quadratic Formula Calculator returns a solution from the entered a, b, and c coefficients.
Matrix Calculator
Matrix Calculator returns the determinant of a two-by-two matrix from its four entered elements.
Sample Size Calculator
Sample Size Calculator estimates observations needed from confidence, expected proportion, and margin of error.
Z-Score Calculator
Z-Score Calculator computes the standard score for an observed value from value, mean, and standard deviation.
P-Value Calculator
P-Value Calculator returns a two-tailed p-value from an entered z-score under a standard normal distribution.
Permutation and Combination Calculator
Permutation and Combination Calculator returns ordered arrangements from entered object and selection counts.
Mean, Median, Mode and Range Calculator
Mean, Median, Mode and Range Calculator summarizes five values with central and spread measures.
Average Calculator
Average Calculator returns the arithmetic mean of five entered values for a quick central estimate.
Variance Calculator
Variance Calculator returns sample variance from five entered observations around their arithmetic mean.
Ratio Calculator
Ratio Calculator returns a quotient and simplified relationship from two entered comparison values.
Exponent Calculator
Exponent Calculator returns the power result from an entered numerical base and integer exponent.
Root Calculator
Root Calculator determines the selected mathematical root from value and degree using the displayed formula.
Log Calculator
Log Calculator returns a logarithm from the entered value and selected numerical base.
Scientific Notation Calculator
Scientific Notation Calculator returns a number from its entered coefficient and power of ten.
Big Number Calculator
Big Number Calculator returns the exact sum of two large integers without floating-point rounding.
Long Division Calculator
Long Division Calculator returns quotient and remainder from an entered dividend and nonzero divisor.
LCM Calculator
LCM Calculator returns the least common multiple shared by two entered positive integers.
GCF Calculator
GCF Calculator finds the largest integer that evenly divides both entered whole numbers.
Factor Calculator
Factor Calculator lists every positive divisor of an entered whole number in ascending order.
Prime Factorization Calculator
Prime Factorization Calculator computes the prime factors of an integer from n.
Area Calculator
Area Calculator returns rectangular area from entered length and width measurements in matching units.
Circle Calculator
Circle Calculator returns circular area from the entered radius using the displayed equation.
Distance Calculator
Distance Calculator returns straight-line distance between two points from their entered coordinate pairs.
Pythagorean Theorem Calculator
Pythagorean Theorem Calculator returns a hypotenuse from the two entered right-triangle legs.
Slope Calculator
Slope Calculator returns vertical change per horizontal change from two coordinate pairs.
Percent Error Calculator
Percent Error Calculator compares an observed value with its accepted reference value.
Percent Off Calculator
Percent Off Calculator returns the sale price from original price and discount rate.
Rounding Calculator
Rounding Calculator returns a rounded number from an entered value and chosen decimal places.
Number Sequence Calculator
Number Sequence Calculator returns an arithmetic-sequence term from first value, common difference, and position.
Basic Calculator
Basic Calculator derives the sum of two numbers from a and b.
Proportion Calculator
Proportion Calculator returns the missing proportional value from three entered terms in equivalent ratios.
Graphing Calculator
Graphing Calculator returns a y-coordinate from entered slope, intercept, and x-coordinate values.
Conversion · 5 calculators
Height Calculator
Height Calculator converts a height value using the entered rate between measurement systems.
Conversion Calculator
Conversion Calculator converts an entered value with a user-supplied conversion rate between units.
Weight Calculator
Weight Calculator changes an entered weight between compatible units using the supplied factor.
Roman Numeral Converter
Roman Numeral Converter returns Roman notation from an entered whole-number value input.
Shoe Size Converter
Shoe Size Converter returns a converted size from the entered value and conversion rate.
Automotive · 6 calculators
Gas Mileage Calculator
Gas Mileage Calculator returns fuel economy from distance traveled and gallons consumed.
Fuel Cost Calculator
Fuel Cost Calculator estimates trip expense from distance, fuel economy, and fuel price.
Mileage Calculator
Mileage Calculator returns distance per fuel unit from distance and fuel consumed.
Horsepower Calculator
Horsepower Calculator estimates engine power from entered torque and revolutions per minute.
Tire Size Calculator
Tire Size Calculator returns overall diameter from section width, aspect ratio, and wheel diameter.
EV Charging Cost Calculator
EV Charging Cost Calculator returns charging expense from electricity used and price per kilowatt-hour.
Electrical · 5 calculators
BTU Calculator
BTU Calculator estimates heating capacity from floor area and BTU per square foot.
Electricity Calculator
Electricity Calculator estimates energy cost from kilowatt-hours and the entered electricity rate.
Voltage Drop Calculator
Voltage Drop Calculator returns circuit voltage loss from entered current and total resistance.
Resistor Calculator
Resistor Calculator returns circuit resistance from entered voltage and current using Ohm’s law.
Ohm's Law Calculator
Ohm's Law Calculator returns circuit voltage from entered electrical current and resistance.
Weather · 3 calculators
Wind Chill Calculator
Wind Chill Calculator estimates perceived cold from entered air temperature and wind speed.
Heat Index Calculator
Heat Index Calculator estimates perceived heat from entered air temperature and relative humidity.
Dew Point Calculator
Dew Point Calculator estimates condensation temperature from entered air temperature and relative humidity.
Science · 6 calculators
Half Life Calculator
Half Life Calculator determines the remaining quantity after radioactive decay from initial, time, and half-life length.
Mass Calculator
Mass Calculator returns an equivalent mass after applying the selected unit conversion factor.
Density Calculator
Density Calculator derives material density from entered mass and volume values in compatible units.
Speed Calculator
Speed Calculator returns travel speed from entered distance and elapsed time measurements.
Molarity Calculator
Molarity Calculator returns solution concentration from entered moles of solute and liters of solution.
Molecular Weight Calculator
Molecular Weight Calculator returns molecular weight from carbon, hydrogen, oxygen, and nitrogen.
Education · 3 calculators
GPA Calculator
GPA Calculator averages four entered grade values into a single academic score.
Grade Calculator
Grade Calculator returns score percentage from points earned and total points available.
Tuition ROI Calculator
Tuition ROI Calculator compares tuition with projected salary gains across entered years.
Developer Tools · 7 calculators
Binary Calculator
Binary Calculator returns a decimal interpretation from the entered binary number input.
Hex Calculator
Hex Calculator interprets an entered hexadecimal number as its base-ten decimal value.
IP Subnet Calculator
IP Subnet Calculator estimates usable IPv4 address space from an entered prefix length.
Bandwidth Calculator
Bandwidth Calculator returns data transfer rate from entered data amount and transfer time in seconds.
Password Generator
Password Generator estimates password entropy from selected length and character-set size inputs.
Base64 Encode Decode
Base64 Encode Decode transforms an entered value using the page’s stated encoding operation.
URL Encode Decode
URL Encode Decode returns transformed text from the supplied URL value and selected operation.
Fun · 3 calculators
Random Number Generator
Random Number Generator estimates a deterministic midpoint within the selected range from min and max.
Dice Roller
Dice Roller returns the expected roll total from dice count and sides per die.
Love Calculator
A fun, deterministic love-name score for entertainment. It does not measure real compatibility or predict relationships.
Other · 1 calculator
What should you know about CalcVerdict?
What is CalcVerdict?
CalcVerdict is a free catalogue of source-cited calculators for finance, health, math, and everyday planning.
How are CalcVerdict results checked?
Each formula is tested against published primary sources, and the page explains its assumptions and citations.
Who writes and checks CalcVerdict?
Written and maintained by Eddy Bo, founder of CalcVerdict. Calculator formulas are checked against the primary authorities listed below, and this catalogue was last reviewed on .
- Appendix J to Regulation Z — APR computations — Consumer Financial Protection Bureau; supports loan payment and APR methodology.
- Publication 550 — Investment Income and Expenses — Internal Revenue Service; supports investment and capital-gains explanations.
- Retirement Benefits — Starting Your Retirement Benefits Early — Social Security Administration; supports Social Security claiming explanations.
“The annual percentage rate is a measure of the cost of credit, expressed as a yearly rate.”
— 12 CFR § 1026.14(a), Consumer Financial Protection Bureau