Geometry & Measurement Calculators
Central Angle Calculator
Find a circle's central angle from an arc length or an inscribed angle.
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What is Central Angle?
A central angle is the angle a sector subtends at the centre. It equals the arc length divided by the radius, or twice the inscribed angle on the same arc.
How it works
From an arc we use θ = s/r (converted from radians); from an inscribed angle we double it. Both degrees and radians are shown.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.