How the steps calculator works
Each step is a solid block as wide as the stairs, one tread deep and as tall as all the risers beneath it. Adding them up gives:
Typical step dimensions
The International Residential Code, which many US jurisdictions adopt, limits stair risers to 7¾ inches and requires treads of at least 10 inches. Comfortable outdoor steps are often around 6–7 inches high with 11–12 inch treads. Keep every riser the same height — uneven steps are a trip hazard.
Before you pour
- Steps attached to a house usually need footings below the frost line; check with your building department.
- Fill large forms partly with clean rubble or gravel to save concrete only if your local code and design allow it.
- Slope treads very slightly so water runs off.
Reference: 2021 International Residential Code, Section R311.7 (stairways). Your local adopted code may differ.
Frequently asked questions
How much concrete for 3 steps?
Three solid steps 4 ft wide with 7-inch risers and 11-inch treads take about 12.8 cubic feet — 24 bags of 80 lb concrete with 10% extra.
What is the standard rise and run for steps?
Under the IRC, risers can be at most 7¾ in and treads at least 10 in. Around 7 in rise and 11 in tread is common.
Do concrete steps need rebar?
Reinforcement is strongly recommended and may be required by code, especially for steps attached to a foundation.