Scientific Calculator

Choose the unit used by the angle you already have. Degrees divide a full turn into 360; the coherent SI unit is the radian, where a full turn is 2*pi. NIST gives the exact relation 360 degrees = 2*pi radians. The setting affects sine, cosine and tangent only.

Tangent is sin(x) divided by cos(x). At 90 degrees, and every odd multiple of 90 degrees, cos(x) is zero, so the quotient would divide by zero. Values close to those angles are valid but can be extremely large, and their sign changes across the pole.

This calculator stays in the real-number system. The real natural and common logarithms are defined only for positive x. Complex logarithms can represent negative arguments, but they require a branch choice and a complex-number output that this form does not claim to provide.

It reports 15 significant digits and rounds half up once at the output. The calculation keeps 50 significant digits internally, including range reduction and the sine and cosine series, so displayed digits are not produced by first converting your input to a binary float.

A negative base raised to an integer is real, so (-2)^3 is -8. A general fractional power is defined through an exponential and logarithm; for a negative base that normally leaves the real numbers. Some special rational exponents do have real values, but decimal text does not uniquely preserve the needed fraction, so this calculator requires an integer.

Every operation uses x. Only x^y uses y, and only sine, cosine and tangent use the angle unit. The other controls stay visible so the same four query-parameter names work in every shareable URL and the calculator remains a plain server-rendered GET form without conditional JavaScript.