How many radians is 180 degrees?

180 degrees equals exactly pi radians (about 3.1416 rad). A full circle is 360 degrees = 2pi rad = 400 grad.

Radians or degrees - which should I use?

Radians are the SI unit and required for trig functions in code (Math.sin/cos take radians). Use degrees for everyday work, radians for math and engineering.

A grad (gon) is 1/400 of a full circle, so 100 grad = 90 degrees. It was introduced with the metric system but rarely used outside surveying.

📐 Angle Converter

Degrees are intuitive but mathematicians use radians. Gradians for surveying/artillery. Turns (full revolutions) is what game engines and GPS use internally.

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Last updated September 10, 2026 — conversions use exact ISO unit definitions.