Degrees vs. Radians: Which Angle Mode Should You Use?

Understand the three common angle units used by scientific calculators and trigonometry.

Degrees

A full circle contains 360 degrees. Degrees are common in elementary and practical geometry. For example, sin(90°) = 1.

Radians

A full circle contains 2π radians. Radians are the standard unit in calculus, mathematical analysis, and many physics formulas. The identity sin(π/2) = 1 assumes radians.

Gradians

A full circle contains 400 gradians. Gradians are used in some surveying and engineering contexts.

How to choose

Match the calculator mode to the units used in the problem. If a problem gives an angle as 30°, use DEG. If it gives π/6, use RAD.