Building concrete steps? You need the right amount of material. Order too little and your project stalls. Order too much and you waste money. This guide shows you exactly how to calculate concrete for any stair configuration.
Understanding Step Dimensions
Before calculating, know these terms:
- Rise - Height of each step (typically 7-8 inches)
- Run - Depth of each step (typically 10-12 inches)
- Width - How wide the steps are
- Total Rise - Total height from ground to landing
- Number of Steps - Total rise ÷ individual rise
Code Requirements
Most building codes require:
- Maximum rise: 7.75 inches
- Minimum run: 10 inches
- Minimum width: 36 inches (44 inches for main entries)
- All steps must be uniform height (within 3/8 inch)
The Basic Formula
Concrete steps are essentially stacked rectangles. Calculate each step’s volume and add them together.
Volume of One Step
Step Volume = Width × Run × Rise
Total Volume for Multiple Steps
Total = Step 1 + Step 2 + Step 3 + ... + Platform
Example: 3-Step Porch Entry
Dimensions:
- 4 feet wide (48 inches)
- 7.5-inch rise per step
- 11-inch run per step
- 3 steps with landing
Calculate Each Component
Step 1 (Bottom):
- Width: 48 in
- Depth: 11 in × 3 = 33 in (includes steps above)
- Height: 7.5 in
- Volume: 48 × 33 × 7.5 = 11,880 cubic inches
Step 2 (Middle):
- Width: 48 in
- Depth: 11 in × 2 = 22 in
- Height: 7.5 in
- Volume: 48 × 22 × 7.5 = 7,920 cubic inches
Step 3 (Top):
- Width: 48 in
- Depth: 11 in
- Height: 7.5 in
- Volume: 48 × 11 × 7.5 = 3,960 cubic inches
Landing (if any):
- Width: 48 in
- Depth: 36 in
- Height: 4 in (slab thickness)
- Volume: 48 × 36 × 4 = 6,912 cubic inches
Total Volume
11,880 + 7,920 + 3,960 + 6,912 = 30,672 cubic inches
Convert to Cubic Feet
30,672 ÷ 1,728 = 17.75 cubic feet
Convert to Cubic Yards
17.75 ÷ 27 = 0.66 cubic yards
Quick Reference Table
| Steps | Width | Rise | Run | Cu Yards |
|---|---|---|---|---|
| 2 | 3 ft | 7.5 in | 11 in | 0.22 |
| 2 | 4 ft | 7.5 in | 11 in | 0.29 |
| 3 | 3 ft | 7.5 in | 11 in | 0.37 |
| 3 | 4 ft | 7.5 in | 11 in | 0.49 |
| 4 | 3 ft | 7.5 in | 11 in | 0.54 |
| 4 | 4 ft | 7.5 in | 11 in | 0.72 |
| 5 | 4 ft | 7.5 in | 11 in | 0.98 |
Add 10% for waste factor
Bags vs Ready-Mix
When to Use Bags
- Projects under 0.5 cubic yards
- Small repairs or single step
- No ready-mix minimum order issues
Bag Coverage
| Bag Size | Yields |
|---|---|
| 40 lb | 0.011 cubic yards |
| 60 lb | 0.017 cubic yards |
| 80 lb | 0.022 cubic yards |
Example: 0.66 cubic yards ÷ 0.022 = 30 bags (80-lb)
When to Use Ready-Mix
- Projects over 1 cubic yard
- Better quality control
- Less physical labor
- Faster pour time
Most ready-mix companies have a 1-yard minimum with short load fees ($50-100) for smaller orders.
2025 Cost Estimates
| Item | Cost |
|---|---|
| 80-lb bag | $6-8 |
| Ready-mix (per yard) | $150-180 |
| Short load fee | $50-100 |
| Rebar (#4) | $8-12 per 20 ft |
| Wire mesh | $5-8 per sheet |
Cost for Our Example (0.66 yards)
- Bags: 30 × $7 = $210
- Ready-mix: $150 + $75 fee = $225
Bags are slightly cheaper for small jobs. But ready-mix saves hours of mixing time.
Reinforcement for Steps
Concrete steps need reinforcement to prevent cracking.
Rebar Grid
- Use #4 rebar (1/2 inch)
- Space 12 inches apart both directions
- Position 2 inches from the bottom
Wire Mesh
- Use 6×6 W1.4/W1.4 mesh
- Place in middle of slab thickness
- Overlap sheets by one square
Which to Choose?
- Light residential: Wire mesh is fine
- Heavy use or freeze zones: Use rebar
- Code requirement: Check local codes
Step-by-Step Pouring Guide
1. Build Forms
- Use 2×8 or 2×10 lumber
- Stake every 2 feet
- Apply form release oil
2. Add Gravel Base
- 4 inches of compacted gravel
- Helps drainage and prevents settling
3. Install Reinforcement
- Support rebar on chairs (2 inches off ground)
- Tie intersections with wire
4. Pour Bottom to Top
- Fill bottom step first
- Work up to the landing
- Vibrate or tap forms to release air
5. Finish
- Screed level with forms
- Edge corners with edging tool
- Broom texture for grip
- Cover and cure 7 days
Common Mistakes
- Wrong step height - Uneven rises cause trips
- Skipping gravel base - Leads to settling and cracks
- No reinforcement - Steps will crack at corners
- Too fast finishing - Wait for bleed water to evaporate
- No curing - Keep moist for 7 days minimum
Alternative: Precast Steps
Don’t want to pour? Precast concrete steps are an option.
| Pros | Cons |
|---|---|
| Instant installation | Limited sizes |
| Consistent quality | Higher cost |
| No curing time | Delivery required |
| Professional look | May need crane |
Cost: $200-600 per precast unit depending on size.
Use Our Free Calculator
Skip the math. Our Concrete Calculator handles all these formulas:
- Enter step dimensions
- Get exact cubic yards
- See bag quantities
- Estimate total cost
For masonry steps with brick or block, try our Masonry Calculator.
Compare Concrete Calculator Tools
Need help choosing the best calculator for your project?
- Best Concrete Calculator 2025 - Compare free and paid options
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Key Takeaway: For most residential step projects, you’ll need 0.3-1.0 cubic yards. Always add 10% waste factor. Consider ready-mix for anything over 0.5 yards to save labor time.