Radius Calculator allows you to calculate the radius, central angle, arc length, and circumference from the span / chord and rise of an arc segment. Built-in unit converter makes it to work with any length unit (including inches, feet, centimeters, meters, and many more).

Simply enter the span / chord and the rise to arc in your choice of units. Then pick the output unit unit and the radius, central angle, arc length, and circumference are instantly computed.

Designed for the multiple trades in the construction industry, this calculator is great for any craftsman who needs to find properties of a circle given curve measurements. In particular, Radius Calculator is perfect carpenters or cabinet makers who deal with curved walls.

Note: There is no closed form solution for the central angle and we use a common approximation for that calculation. This method is very accurate for small angles and about 10% off on large angles approaching 180 degrees.

What’s New

Version 7.0.0

- iOS 12 support
- iPhone XR/XS/XS Max support

Ratings and Reviews

4.9 out of 5
35 Ratings

35 Ratings

Sharon (WoodChick) ,

Incredibly Useful and Efficient

I do a lot of radius woodwork. This app saves me from waiting until I get back to my desk to figure out the radius of whatever project I'm producing.
I recommend this to anyone in construction. It surely has other uses as well for other trades.

Ou812oip ,


Awesome app . Best thing since sliced bread!

Shaun Layton ,

Great Arc App

I am a general contractor and was trying to figure out the radius of the arc over a garage door header, I downloaded the app and had the radius in about one minute. It would of taken me 20 min to figure it out! 1.99 app saved me about $ 12 in labor.


MaoWare Corporation
21.5 MB

Requires iOS 10.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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