Stair Rise and Run: Code and Comfort

Under the International Residential Code (IRC), stair risers can be at most 7¾ inches and treads must be at least 10 inches deep. Comfortable stairs usually land around 7 inches of rise with 11 inches of tread. Your local code may differ.

How many steps do you need?

Number of risers = Total rise (in) ÷ 7.75, rounded UP Actual rise = Total rise ÷ number of risers
Total riseRisersActual rise each
14 in27 in
21 in37 in
28 in47 in
30 in47.5 in
36 in57.2 in
42 in67 in

The comfort rule

A long-standing rule of thumb is that two risers plus one tread should total about 24–25 inches. 7 + 7 + 11 = 25 fits nicely. Outdoor steps often use a slightly lower rise and deeper tread.

Keep every step the same

Variation between risers is a major trip hazard; codes limit it to about 3/8 inch within a flight. Measure total rise from the finished surfaces at the top and bottom.

Calculate concrete for solid steps with the concrete steps calculator.

Reference: 2021 International Residential Code, Section R311.7. Check the code your city or county has adopted.

Last reviewed November 1, 2026. Results are estimates — confirm with your supplier.

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