Circle, Arc & Arch Calculator

Radius, arc length and layout marks for an arch from its width and rise — or circumference and area from a diameter. Free, no sign-up.

For an arched window, doorway, rake wall or curved deck edge: measure the straight width (the chord) and how high the arch rises at the middle. You get the radius to swing it from, where the centre point sits, and the arc length for trim.

No trammel room? Use the layout table: measure along the chord from one end and mark the height of the curve at each station, then bend a batten through the marks.

Taulien Construction · Fredericton, New Brunswick · info@taulien.com · 506-230-5131