Part of the topic: 🏠 Home, energy & car
Right triangle calculator (sin, cos, tan, cot)
Choose which two values you know. a and b are the legs, c the hypotenuse, α the angle opposite a. The calculator solves the triangle with trigonometry.
Voluntary support · Thank-you gift: our checklist PDF · Secure checkout via Digistore24 (Apple Pay, Google Pay, PayPal, card)
🔒 Runs entirely in your browser – nothing you enter is uploaded or stored.
How to use it
- Select which two values you know.
- Enter them – angles in degrees.
- Read all sides, angles, area and the trigonometric values.
Last checked: October 2026 · Based on: Pythagorean theorem, trigonometric functions in a right triangle. Found a mistake? Use the form below – we fix confirmed errors and update the date.
Frequently asked questions
What is the cotangent?
The cotangent is the reciprocal of the tangent: cot α = 1 / tan α = adjacent ÷ opposite.
Which side is the hypotenuse?
The side opposite the right angle – it is always the longest side.
Where is this used in practice?
Roof pitch, ramps, stairs, cable lengths, surveying and any task where a height and a horizontal distance meet at a right angle.