Math Calculator

Arctan Calculator

Enter any real number to get the principal arctan angle.

Enter a tangent value

Any real number is allowed for tan θ.

Clear

About this calculator

How to use Arctan Calculator, plus the formulas and logic behind the results.

Tool description

Arctan returns the unique angle in (−π/2, π/2) whose tangent equals the input.

How to use

  1. Review the input fields and choose degrees or radians when asked.
  2. Enter the known values using consistent units.
  3. Select Calculate to view results.
  4. Adjust inputs and recalculate as needed.

Formulas & reference

  • θ = arctan(x)

Trig tips

  • Confirm angle mode (degrees vs radians) before evaluating sin, cos, tan.
  • Right-triangle tools assume a 90° angle between legs a and b.
  • Triangle inequality: each side must be shorter than the sum of the other two.

Calculation logic

Calls atan and formats both degree and radian results.

Educational calculator. Floating-point rounding may differ slightly from textbook answers.

Arctan Calculator FAQ

Common questions about this calculator and how to use the results.

What is the Arctan Calculator?

An online math tool on LeCalculators that solves arctan calculator problems with clear numeric results for study and everyday use.

Do I use degrees or radians?

Many trig tools include an angle mode selector. Match the mode to how your angle is written—degrees (°) or radians.

Why is my answer undefined or invalid?

Trig functions have domain limits (for example arcsin needs −1…1). Triangle tools also reject sides that violate the triangle inequality.

How precise are the results?

Results use floating-point math and are rounded for display with mathFormat. Tiny rounding differences vs hand calculation are normal.

Is this calculator free?

Yes. LeCalculators trigonometry tools are free to use in your browser with guides and FAQs on each page.

Can I use this for homework?

Yes—use it to check work. Always show your own steps when your teacher requires a written solution.