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Quick answer
What does the Stair rise & run planner calculate?
What step count, rise, run, and stair length fit the total height you enter? This calculator uses total floor-to-floor rise, target riser height, planned tread depth, and maximum riser height to check to estimate concept stair geometry immediately in your browser.
With the values currently entered, the result is 16 risers — fits the entered maximum riser. It also shows actual riser height, treads, horizontal run, straight stringer length, and 2 × rise + tread check.
How to use the Stair rise & run planner
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Total floor-to-floor rise — entered in m
- Target riser height — entered in mm
- Planned tread depth — entered in mm
- Maximum riser height to check — entered in mm
Stair rise & run planner formula
Risers = ceiling(total rise ÷ target riser); actual riser = total rise ÷ risers; treads = risers − 1
Assumptions
- The stair is a single straight flight with equal risers and one fewer tread than risers.
- The entered maximum is only a user check, not a supplied building-code limit.
Practical guide
Stair rise & run planner example and edge cases
What step count, rise, run, and stair length fit the total height you enter? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical stair rise & run planner scenario
For this example, use total floor-to-floor rise of 2.8 m, target riser height of 175 mm, planned tread depth of 280 mm, and maximum riser height to check of 190 mm. These are starting values, so replace them with numbers that match your situation.
- Total floor-to-floor rise
- 2.8 m
- Target riser height
- 175 mm
- Planned tread depth
- 280 mm
- Maximum riser height to check
- 190 mm
Calculated result16 risersfits the entered maximum riser
Start with fits the entered maximum riser. Then check actual riser height, treads, horizontal run, straight stringer length, and 2 × rise + tread check to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for actual riser height, treads, horizontal run, straight stringer length, and 2 × rise + tread check explain how the estimate is built.
- The method is Risers = ceiling(total rise ÷ target riser); actual riser = total rise ÷ risers; treads = risers − 1. Keep the units consistent and use values from the same time period.
Edge cases worth checking
When total floor-to-floor rise is unusual
The stair is a single straight flight with equal risers and one fewer tread than risers. Double-check this input before relying on the result.
When maximum riser height to check is uncertain
The entered maximum is only a user check, not a supplied building-code limit. Run a lower and higher value to see a useful range.
What changes the result most
Total floor-to-floor rise
Measure total floor-to-floor rise with the same unit shown beside the input. Convert first if your source uses another unit.
Target riser height
Measure target riser height with the same unit shown beside the input. Convert first if your source uses another unit.
Planned tread depth
Measure planned tread depth with the same unit shown beside the input. Convert first if your source uses another unit.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Total floor-to-floor rise: 10% lower
2.52 m15 risersfits the entered maximum riser
Total floor-to-floor rise: 10% higher
3.08 m18 risersfits the entered maximum riser
Target riser height: 10% higher
193 mm15 risersfits the entered maximum riser
Common mistakes
Check total floor-to-floor rise
The stair is a single straight flight with equal risers and one fewer tread than risers. Make sure this matches the number you enter.
Keep maximum riser height to check consistent
The entered maximum is only a user check, not a supplied building-code limit. Use the same units and time period throughout the calculation.
Do not rely on one stair rise & run planner scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What step count, rise, run, and stair length fit the total height you enter?
Confirm measurements, pack sizes, and product instructions before ordering materials.