When to use this calculator
Find the horizontal run of a straight stair from riser count and tread going. Assumes the top landing acts as the final tread; nosings and landings are excluded.
Explore the material quantities calculators for other questions in this topic. For a related calculation, use the Tile Adhesive Quantity Calculator: Convert an adhesive consumption rate into whole bags for a tiling area.
PUTTING IT INTO PRACTICE
Stair Tread Run: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Number of risers (integer) | 16 |
| Tread going (mm) | 250 |
| Result | 3,750 mm |
- Check the input labels and enter the example values above.
- Apply the relationship: Straight run = (risers−1) × tread going.
- The result is 3,750 mm, rounded for display.
How to interpret your result
Assumes the top landing acts as the final tread; nosings and landings are excluded.
Calculate net geometric quantities first, then apply a project-specific allowance where appropriate. Coverage per bag or pack should come from the product label. Bulk density, trimming and compaction can substantially change order quantities.
Frequently asked questions
Does a geometric estimate include waste automatically?
Only when a waste or allowance input is provided. Otherwise add an appropriate allowance separately before ordering.
When is the stair tread run calculator useful?
Find the horizontal run of a straight stair from riser count and tread going. Assumes the top landing acts as the final tread; nosings and landings are excluded.
How do I use the stair tread run calculator?
Enter number of risers (integer), tread going (mm). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Straight run = (risers−1) × tread going.
What should I check before using the result?
Assumes the top landing acts as the final tread; nosings and landings are excluded.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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