Degrees to radians: 1° = π/180 radians
One degree is π/180 radians, and one radian is 180/π degrees - so multiply by π/180 going into radians and by 180/π coming out. Radians are the unit calculus assumes, which is why arc length, sector area and every derivative of a trig function require them. Getting caught in degree mode is the single most common source of wrong answers on a calculator.
Related Basics identities
Common questions
What is the Degrees ↔ radians identity?
One degree is π/180 radians, and one radian is 180/π degrees - so multiply by π/180 going into radians and by 180/π coming out. Radians are the unit calculus assumes, which is why arc length, sector area and every derivative of a trig function require them.
When do you use the Degrees ↔ radians identity?
Getting caught in degree mode is the single most common source of wrong answers on a calculator.
Which identities are related to Degrees ↔ radians?
Degrees ↔ radians belongs to the Basics group. The identities used alongside it most often are SOHCAHTOA, Arc length and Sector area.
Practise it
Reading a formula is not the same as recalling it under time pressure. The workspace drills Basics questions in the quiz, and the triangle solver shows a worked solution for any triangle you type in.
Or browse all 45 identities in the full reference, or read the trigonometry guides for the method behind them.