Stair Calculator
Free online stair calculator for perfect stairs
About Stair Calculator
Stair Calculator is a free online stair calculator built for homeowners, contractors and DIY builders who want safe, comfortable, code-conscious stairs. Enter your total rise and run to get the number of risers and treads, individual riser height, tread depth, stringer length, stair angle and total run — all calculated instantly in your browser. The tool helps you balance riser and tread proportions, estimate stringer board length, and plan stair layouts for straight staircases with confidence. No sign-up, no downloads and no fees: just enter your measurements and get clear, printable-style results you can take to the workshop or job site.
What Stair Calculator does
AINave analysisCalculate the riser count, riser height, total run, stringer length and angle for a straight staircase from rise and tread inputs.
- Best for
- HomeownersContractorsDIY builders
- Use it to
- Plan the layout of a straight staircase from floor-to-floor height
- Check riser and tread dimensions against residential code limits
- Estimate stringer length and stair angle before cutting
- Verify headroom and total run against available floor space
- Export stair layout results as a PDF for inspection or a cut list
- Run calculations on site from a phone or tablet
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