The Radius of an Arch calculator computes the radius (r) of a circle that would trace an arc of a certain chord length (c) and at a certain height (h).
INSTRUCTIONS: Choose units and enter the following:
Radius of Arch (r): The calculator returns the radius is in inches. However, this can be automatically converted to numerous other length units (e.g. centimeters or yards) via the pull-down menu.
The Radius of an Arch calculator computes the radius of a circle that can be used to mark an arch based on the cord length of the arch and the height of the arch. Arches on buildings and arched railings can be built using this formula. The following is a video (YouTube) that shows the use of this equation to build an arched railing on a porch.. This can also be used to trace lines for painted arches as in the photograph of arches painted on a barn door (Special thanks to my friend Austin).
`r = c^2 / (8*h) + h/2`
Arches Painted on Barn Door
Let's use my neighbor's sliding barn doors as our working example. But you'll see that it works for any application.
Viola! You're done. You now have a perfectly rounded arch drawn on your material, and you can paint or cut with precision.