Trigonometry Calculator

Nine in total: the three forward functions sin, cos, and tan; their inverses asin, acos, and atan; and the reciprocals csc (1 / sin), sec (1 / cos), and cot (1 / tan). Pick a function, enter the angle or value, and the result is rounded to six decimals.

Both. Forward functions take an angle plus a unit toggle (degrees or radians). Inverse functions output the angle in both units at once, so you can read pi/6 or 30 degrees side by side without converting yourself.

Because it is undefined there. tan equals sin divided by cos, and cos(90 degrees) is zero, so the ratio blows up to infinity. The same happens at 270 degrees, 450 degrees, and every odd multiple of 90 degrees. sec hits the same singularity, while csc and cot are undefined at 0 degrees, 180 degrees, and every multiple of 180 degrees.

Only values from -1 to 1, inclusive. Sine and cosine never produce numbers outside that range, so their inverses are not defined for inputs like 2 or -1.5. Enter such a value and the calculator returns no result. atan is the exception: it accepts any real number, including very large ones, and the output approaches plus or minus 90 degrees (or plus or minus pi/2).

Every numeric result is rounded to six decimal places. That is enough precision for textbook trigonometry, surveying, and engineering rough work, while keeping the display readable. Internally the calculator uses double-precision floating-point math, then rounds at the last step.