How to use the circular arch radius calculator
Find the radius and centre position of a circular arch from its span and rise. Enter span width, rise height in the fields above; the arch radius, centre below top of arch are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “circular arch radius”, “arch geometry”, “radius of arch from span and height”, “calculate circular arch radius”, “find arch radius”.
Formula
Variables
- span — Span width (m)
- rise — Rise height (m)
Worked example
With span width = 10 m, rise height = 3 m, the calculator gives arch radius ≈ 5.666667 m; centre below top of arch ≈ 2.666667 m.
Frequently asked questions
What is the circular arch radius calculator used for?
Find the radius and centre position of a circular arch from its span and rise. It helps with questions such as “circular arch radius”, “arch geometry”, “radius of arch from span and height”.
What is the formula for the circular arch radius calculation?
Arch radius (m) = (span × span / 4+rise × rise) / (2 × rise). Centre below top of arch (m) = [Arch radius]-rise. Here span is span width (m), rise is rise height (m).
What inputs do I need for the circular arch radius calculator?
You need span width in m, rise height in m. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the circular arch radius calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the circular arch radius result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.