Why do radians use π?

A full circle is 2π radians because the radian is defined as the angle where arc length equals the radius, and a circle's circumference is 2πr.

Angle Converter

Convert an angle measured in degrees to radians, and vice versa is available by entering a negative degree offset.

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Formula

radians = degrees × (π / 180)

Prefer a quick-reference chart instead? Degrees to Radians, Radians to Degrees

Converting Angles and Land Area Between Measurement Systems

The degrees-to-radians conversion and common area unit conversions explained with real examples.

Length Converter

Convert length between meters, feet, inches, and miles.

Weight Converter

Convert weight between kilograms, pounds, ounces, and stones.

Temperature Converter

Convert temperature between Celsius, Fahrenheit, and Kelvin.

Speed Converter

Convert speed between km/h, mph, and m/s.

Data Storage Converter

Convert digital storage between bytes, kilobytes, megabytes, gigabytes, and terabytes.

Area Converter

Convert area between square meters, square feet, and acres.