Stair Calculator
Find riser height, tread count, run and stringer length. The result updates as you type, with the working underneath so you can check it.
Your details
Result
Number of risers
15
- Riser height
- 180.0 mm
- Treads
- 14
- Total run
- 3,500 mm
- Stringer length
- 4,420 mm
- Pitch
- 35.8°
- 2R + G rule
- 610 mm (comfortable)
- Check your local building code for maximum riser, minimum going and headroom.
Good to know: risers = ⌈rise ÷ max riser⌉
Please note: Estimates only. Measure your actual space, buy a little extra, and check product labels, safety requirements and local building rules. Do not rely on this for structural or safety-critical work.
About this tool
Formula
risers = ⌈rise ÷ max riser⌉
Questions people ask
What is the 2R + G rule?
Twice the riser plus the going should be 550–700 mm for a comfortable stair.
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How we calculate this
We use the standard published formula or definition for this calculation, and we show the working so you can check it.
Spotted a mistake? Tell us and we'll check it. How we check our calculators