What units does the calculator use?

Input is in degrees. We convert to radians internally: tan(degrees × π/180).

When is tan undefined?

Tangent is undefined at 90°, 270°, etc. (cos = 0). For such angles we show an error.

Calculate tangent of an angle. Enter angle in degrees to get tan(angle).

Angle (degrees)

What units does the calculator use?: Input is in degrees. We convert to radians internally: tan(degrees × π/180).
When is tan undefined?: Tangent is undefined at 90°, 270°, etc. (cos = 0). For such angles we show an error.

Celsius to Fahrenheit Converter

Convert Celsius to Fahrenheit and Fahrenheit to Celsius instantly. Free temperature converter.

Tip Calculator

Calculate tip and split the bill. Enter bill amount, tip percentage, and number of people.

Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals to numbers. Supports 1–3999.

Combinations Calculator

Calculate C(n,r) — the number of ways to choose r items from n without order. Uses n!/(r!(n-r)!).

Combinations with Replacement Calculator

Calculate the number of ways to choose r items from n with repetition allowed. Formula: C(n+r-1, r).

Even Permutations Calculator

Count how many permutations of n objects are even (expressible as an even number of swaps). For n ≥ 2, equals n!/2.