Mathematics, physics, and design basics · Geometry

Circle area and circumference

Calculate a circle’s area and circumference from its radius.

Published · R0

Method and scope

Circumference C = 2πr. Area A = πr².

Calculate standard circle measures for learning and basic layout estimates. Intended for Learners, Early estimates.

Inputs

SOURCE AND LIMITS

Assumptions: The shape is an exact circle and the entered value is its radius.

Limitations: A measured or built circle may not be geometrically exact.

Method version 1.0.0 · Unit registry and result provenance are shown after calculation. This tool is limited to the documented scope.

See the other currently released formula calculators tagged for these research fields.