DIY & materials · Calculator companion · By K Imports
Stair rise and going: practical guide
This guide explains how to use the Count.ie stair rise and going. Explore riser count, stair run, angle and footprint. Follow the inputs, method and worked example below, then compare your own scenario.
Guide written .
Open the Stair rise and going calculatorWhat to prepare
- Measure the actual space and record every dimension with its unit.
- Check the supplier's pack size, stated coverage and installation instructions.
- Separate the measured requirement from waste, cuts, overlaps and spare material.
Understand the inputs
The calculation method
Risers = ceiling(total rise ÷ target riser), with at least two. Treads = risers − 1; comfort expression = 2 × rise + going.
Worked example
Illustrative inputs and their result.
Example inputs
- Floor-to-floor rise (mm)
- 2800
- Target maximum riser (mm)
- 180
- Tread going (mm)
- 250
- Stair width (mm)
- 900
Calculated example result
- Risers
- 16
- Actual Riser MM
- 175 mm
How to interpret the result
The calculated quantity is a planning estimate, not an installation specification. Whole packs and site conditions can change the order; structural or safety-critical work needs appropriate professional guidance.
Compare alternative dimensions or pack sizes without changing the unit basis. Re-measure uncertain areas before buying, and use the manufacturer's instructions to decide a suitable allowance.
Common mistakes to avoid
- Convert millimetres, centimetres and metres before combining measurements.
- Do not add the same waste allowance at both measurement and ordering stages.
- Check irregular shapes, openings, substrate conditions and manufacturer coverage separately.
Assumptions and sources
Geometry only. The comfort expression is not an Irish compliance check. Headroom, landings, guarding, accessibility and applicable building rules require design review.
If your case falls outside this scope, use a more suitable calculator or contact us about an unclear method.