The Engineer's Ephemeris

Arc Geometry Calculator

Compute arc length, chord, sagitta, radius, and sector area from minimal inputs. Useful for profiling, slotting, and inspection where circular segments appear.

Units:

Result A mm

Formula: Let ΔH = (H2 − H1). Then A = √(2R·ΔH − ΔH²), with 0 ≤ ΔH ≤ 2R. A is the horizontal distance from the centerline to the arc at height H2.
A H1 H2 R
Arc…dotted = extension Radius R Horizontal distance A at height H2; H1 marks arc bottom.