Concrete Calculator Examples
Follow worked examples for a concrete slab, round footing, hollow tube, curb and gutter, and solid concrete stairs with bag estimates.
How should you use these Concrete Calculator examples?
These examples turn the Concrete Calculator inputs into complete scenarios with stated values, calculation steps, and interpreted results. Use them to check how the calculator behaves, compare your own situation with realistic cases, and identify which inputs have the greatest effect before relying on an estimate.
Example 1: Concrete Slab
A 5 ft by 2.5 ft slab with 5 in thickness and quantity 1 has this net volume:
That is 0.1929 yd³ or 0.1475 m³. With no waste and bag yields of 0.45 ft³ and 0.60 ft³, the purchase counts round up to 12 sixty-pound bags or 9 eighty-pound bags.
Example 2: Round Footing
A 2.5 ft diameter footing that is 6 ft deep has a net volume of approximately 29.45 ft³, or 1.091 yd³. A 10% allowance increases the planning order to approximately 1.200 yd³.
Example 3: Hollow Circular Slab
For a 5 ft outer diameter, 4 ft inner diameter, and 6 in thickness, subtract the 4 ft opening from the 5 ft outer cylinder. The result is approximately 3.534 ft³ before waste.
Example 4: Curb and Gutter
Using a 4 in curb depth, 4 in curb height, 10 in gutter width, 5 in flag thickness, and 10 ft length gives approximately 4.583 ft³ before waste. The model assumes two connected rectangular cross-sections.
Example 5: Concrete Stairs
For 5 risers, a 12 in run, 6 in rise, 50 in width, and 5 in top platform, the solid stair model yields approximately 35.590 ft³ before waste. This is a solid stepped model; voids or different landings need separate calculations.
Compare the Five Shapes
| Project | Primary dimensions | Checked net volume |
|---|---|---|
| Slab | 5 ft × 2.5 ft × 5 in | 5.208 ft³ |
| Round footing | 2.5 ft diameter × 6 ft | About 29.45 ft³ |
| Hollow slab | 5 ft outer, 4 ft inner, 6 in | About 3.534 ft³ |
| Curb and gutter | Two rectangular cross-sections × 10 ft | About 4.583 ft³ |
| Solid stairs | 5 risers with entered run, rise, width, platform | About 35.590 ft³ |
Reproduce an Example
- Select the matching shape.
- Enter the dimensions and units exactly as listed.
- Set Quantity to 1.
- Set Waste allowance to 0% to reproduce net reference geometry, or enter an order allowance.
- Select Calculate and compare net volume before using the rounded order value.
Corrections and Review
Report an issue or error in the calculator using the Contact Us page.