About The Stair Calculator
The Stair Calculator is a free, browser-based tool that turns rise/run measurements into clear numbers and a diagram you can build from. It’s designed for DIYers, carpenters, inspectors, and anyone who needs stair math they can trust. Our goal is simple: reduce layout guesswork, catch code issues early, and help you finish stairs that feel comfortable and pass inspection.
Why Choose Us?
Having years of experience in the construction industry, we understand how challenging it can be to get stair measurements right. That’s why we created our Stair Calculator to make the process simple and accurate for everyone. This powerful tool is completely free to use and helps you design perfect stairs in just a few clicks. We don’t charge any fees for using the calculator, but if you’d like to support our work, you’re welcome to donate voluntarily. Try our Stair Calculator today and make stair design easier than ever!
How the Calculator Works
Enter your total rise, choose a tread depth, and toggle options like nosing, headroom, landing thickness, and unit system (imperial/metric). The tool instantly returns:
Input
Step count & actual riser height
Results
Total run & stair angle (pitch)
Review
Stringer length & layout points
Use your results on the site
Accuracy, Assumptions & Code Notes
We base calculations on widely used residential rules of thumb and modern code expectations, while letting you change inputs to match your project.
- Default guards help keep risers within a tight tolerance and flag out-of-range angles.
- Deck mode accounts for open risers, gaps, and common outdoor details; interior mode assumes finished risers unless you say otherwise.
- Local code always wins. Dimensions can vary by jurisdiction—use our results as a planning aid, then confirm with your building department and measure the actual structure before cutting.
Accessibility, Privacy & Trust
We keep the experience fast, readable, and inclusive.
- Accessibility: labeled inputs, keyboard-only operation, and live announcements for updates.
- Privacy: calculations run in your browser; we don’t store your measurements server-side.
- Expert review: releases are reviewed by a licensed contractor for clarity and field realism.
- Change log: major updates are documented so you can see what changed and why.