Geometry, without the detour
Every circle has an answer.
Six free, focused tools for circle geometry and workshop layout. Enter what you know. Get the measurements you need.
01No account02Clear formulas03Mobile ready
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AVAILABLE FORiPhone + AndroidPick the problem
One job per calculator.
No crowded menus. Each tool puts the inputs, results and formula on one page.
01
Core geometry
Circle Calculator: Radius, Diameter, Circumference & Area
Open tool ↗02Curves & bends
Arc Length Calculator
Open tool ↗03Slices & sweeps
Sector Area, Arc Length & Perimeter Calculator
Open tool ↗04Arches & cut lines
Circle Chord & Segment Calculator
Open tool ↗05Rings & washers
Annulus & Ring Area Calculator
Open tool ↗06Workshop layout
Bolt Circle & PCD Coordinate Calculator
Open tool ↗
Latest field note
Is Circle Calculator Free? Free Web Tools, Core App Calculators, and Optional Pro
See what Circle Calculator offers free on the web and in the app, what optional Pro adds, and where to verify current subscription terms before paying.
Beyond the browser
A circle toolkit that goes to the job.
Circle Calculator adds measured diagrams, local history, favourites and projects. Core calculations and bundled pipe charts work offline; selected Pro workflows add PDF, CSV and DXF exports.
- 01Circle, arc, sector, segment, chord and annulus
- 02Bolt-circle coordinates and workshop tools
- 03Saved work with light, dark and AMOLED themes
Start with what you know