Circle Calculators — Mathematics
Circle geometry: area, circumference, sector perimeter, segment area, the equation of a circle, and circle theorems. Segment and sector are the pair people mix up, so check which region you actually need before entering an angle.
All Circle Calculators
Calculate area of acircle with inputs, formulas, and instant results.
Calculate circle sector perimeter with inputs, formulas, and instant results.
Calculate circle theorems with inputs, formulas, and instant results.
Calculate circumference with inputs, formulas, and instant results.
Calculate coin rotation paradox with inputs, formulas, and instant results.
Calculate equation of acircle with inputs, formulas, and instant results.
Calculate semicircle area with inputs, formulas, and instant results.
Calculate slant height with inputs, formulas, and instant results.
Calculate sphere calc find vad with inputs, formulas, and instant results.
Calculate square in acircle with inputs, formulas, and instant results.
Calculate string girdling earth with inputs, formulas, and instant results.
Calculate surface area to volume ratio with inputs, formulas, and instant results.
Calculate tangent of acircle with inputs, formulas, and instant results.
Calculate tetrahedron volume with inputs, formulas, and instant results.
Calculate torus surface area with inputs, formulas, and instant results.
Calculate surface area of atriangular prism with inputs, formulas, and instant results.
Calculate arc length of a circle
Calculate area, circumference, and diameter
Calculate area of a circle sector
Calculate surface area of 3D shapes
About Circle Calculators
Circle geometry: area, circumference, sector perimeter, segment area, the equation of a circle, and circle theorems. Segment and sector are the pair people mix up, so check which region you actually need before entering an angle.
Whether you need to solve a one-time problem or verify your own calculations, these free tools cover the most common circle scenarios. All results are computed in your browser — no data is sent to any server.
What You Can Calculate
This section includes 20 tools: Area of a Circle Calculator, Circle Sector Perimeter Calculator, Circle Theorems Calculator, Circumference Calculator, Coin Rotation Paradox Calculator, Equation of a Circle Calculator, Semicircle Area Calculator, Slant Height Calculator, and 12 more. Each calculator is free to use with no signup required.