Staircase Riser and Tread Calculator
Design safe, comfortable stairs with precise measurements
Stair Dimensions
Unit of Measurement
Vertical distance from bottom to top floor
Horizontal distance available for stairs
Recommended: 7-7.75 inches (178-197 mm)
Recommended: 10-11 inches (254-279 mm)
How much the tread overhangs the riser
Usually 11.25 inches (2×12 actual size)
Calculation Results
Number of Risers
–
Riser Height
–
Each step will rise this amount
Tread Depth
–
Horizontal depth of each step
Total Run
–
Total horizontal length
Stringer Length
–
Length of each stringer
Stair Angle
–
Angle of incline
Stair Visualization
This visualization shows the side profile of your staircase.
Understanding Stair Terminology
Rise & Run
Rise refers to the vertical height of each step. The building code generally recommends a maximum rise of 7.75 inches (197 mm).
Run refers to the horizontal depth of each tread. The building code generally recommends a minimum run of 10 inches (254 mm).
Treads & Risers
Treads are the horizontal parts of the stairs that you step on.
Risers are the vertical parts of the stairs connecting one tread to the next.
Nosing
Nosing is the edge of the tread that protrudes beyond the face of the riser. Building codes typically require 3/4 to 1-1/4 inches (19-32 mm) of nosing.
Stringers
Stringers are the structural supports that hold the treads and risers. They typically run diagonally from the bottom to the top of the staircase.
Building Code Requirements
| Parameter | Imperial | Metric | Notes |
|---|---|---|---|
| Maximum Riser Height | 7.75 inches | 197 mm | Smaller risers create safer, more comfortable stairs |
| Minimum Tread Depth | 10 inches | 254 mm | Measured from nosing to nosing |
| Nosing Projection | 0.75 – 1.25 inches | 19 – 32 mm | Measured from face of riser |
| Minimum Headroom | 6 feet 8 inches | 2032 mm | Measured vertically from tread nosing |
| Minimum Width | 36 inches | 914 mm | Clear width between walls or railings |
| Riser/Tread Consistency | 3/8 inch max variation | 9.5 mm max variation | Between largest and smallest in a flight |
Note: Building codes can vary by location. Always check your local building codes before constructing a staircase.
Frequently Asked Questions
What is the ideal rise and run for stairs?
The ideal rise is typically between 6.5 and 7.75 inches (165-197 mm), while the ideal run (tread depth) is usually between 10 and 11 inches (254-279 mm). A common guideline is that the rise multiplied by the run should equal approximately 75 inches (1905 mm).
How do I calculate the number of steps needed?
Divide the total rise (floor-to-floor height) by your desired riser height. Round to the nearest whole number to get the number of risers needed. The number of treads will be one fewer than the number of risers.
What is the standard stair width?
The standard minimum stair width for residential purposes is 36 inches (914 mm), though wider stairs (42-48 inches) provide more comfort and accessibility.
What is the 7-11 rule for stairs?
The 7-11 rule is a common guideline suggesting that the rise should be around 7 inches and the run around 11 inches. This creates stairs that are both comfortable and safe for most people.