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Calculate riser height, tread depth, and stringer length with code validation.
A stair calculator determines riser height, tread depth, stringer length, and angle from total rise and step count, with building code validation.
| Specification | Value |
|---|---|
| Max Riser Height | 7.75″ (IRC) |
| Min Tread Depth | 10″ (IRC) |
| Rise + Run Rule | 17″ – 18″ ideal |
| Min Width | 36″ (IRC) |
| Max Riser Variation | 3/8″ between steps |
| Min Headroom | 6 ft 8 in |
Formula
Riser Height = Total Rise ÷ Number of Steps; Stringer = √(Rise² + Run²)Total Rise = floor-to-floor height in inches
Steps = number of risers
Tread Depth = horizontal depth of each step
Worked Example
108″ total rise, 14 steps, 10.5″ tread depth
Did you know? Falls on stairs account for over 1 million injuries per year in the U.S., making proper riser consistency (within 3/8″ variation) a critical safety requirement (source: National Safety Council).
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