Circle Calculators
4 free circle calculators in the Geometry & Measurement category. Each tool gives instant results and explains the formula so you can follow the calculation.
Arc Length Calculator
Arc = 2 pi r x (angle/360); Sector area = pi r^2 x (angle/360)
Open calculator โCircle Area Calculator
Area = pi x r^2; Circumference = 2 x pi x r
Open calculator โCircumference Calculator
Area = pi x r^2; Circumference = 2 x pi x r
Open calculator โCircumference-to-Diameter Calculator
Diameter = circumference / pi
Open calculator โAbout circle calculations
This page groups the circle tools within Geometry & Measurement. Pick a calculator above to enter your values and get an instant result, complete with the formula, a step-by-step breakdown and a worked example. All calculators are mobile-friendly, accessible and free.
What are circle calculators used for?
These tools help you with circle calculations in the geometry & measurement category, giving instant results with the formula and a worked example on each page.
Are they free and private?
Yes. They are free, require no sign-up, and run entirely in your browser so your inputs stay on your device.