# Arctan Calculator (Tan Inverse)

> Enter a tangent ratio and get the angle back in degrees and radians. Handles the tan inverse notation tan⁻¹(x), names the exact angle for standard ratios, and gives the general solution.

**URL:** https://www.calculatoranswers.com/arctan-calculator
**Category:** Education

## Quick Answer

Find the angle whose tangent is a given number. Enter the ratio and read the principal value in degrees and radians, strictly between -90° and 90°.

## Definition

An arctan calculator evaluates the inverse tangent, written arctan(x), tan⁻¹(x), or atan(x). It answers the reverse of the tangent question: given a ratio, which angle produces it? The notation tan⁻¹ marks a function inverse rather than a reciprocal power, so it is not the same as cotangent, cot(x) = 1/tan(x). Arctan accepts every real number, unlike arcsin and arccos, and returns the principal value in the open interval from -π/2 to π/2 radians.

## How to Use

1. **Enter the tangent ratio** — Type the value of x, the ratio whose angle you want. Any real number is allowed, including negatives and values greater than 1.
2. **Choose degrees or radians** — Switch the output unit to match the problem you are working on.
3. **Read the angle** — The principal value appears in both units, with the exact form named when the ratio is one of the standard cases.

## Disclaimer

This calculator provides estimates for educational and planning purposes. Always consult a qualified professional for specific advice on financial, medical, legal, or other regulated decisions.

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