Unit system
Waste
%
| Shape / Type | Dimensions | Qty | Volume |
|---|
Choose a shape, enter dimensions, adjust quantity, and the volume will update automatically.
Total (with waste)+5%
0.000 yd³
= 0.000 ft³ • 0.000 m³
Bag count (approx.)brand yields vary
80‑lb: 0 • 60‑lb: 0 • 50‑lb: 0 • 25‑kg: 0
Assumed yields: 80‑lb≈0.60 ft³ • 60‑lb≈0.45 ft³ • 50‑lb≈0.375 ft³ • 25‑kg≈0.011 m³
Tip: For larger pours, compare to truck capacities (e.g., ~10 yd³ or ~7 m³ typical).
Formula used
- Rectangular prism (slabs, walls, beams/footings): V = L × W × H. Thickness is converted (in→ft or cm→m) before multiplication.
- Cylinder (columns, tubes, post holes): V = π × (D/2)² × H, with diameter converted to length unit first.
- Stairs (wedge approximation): treat the stair run–rise as a triangular prism: V ≈ 0.5 × Run × Rise × Width.
- Waste allowance: Vfinal = Vsum × (1 + waste%).
- Bag counts (approx.): divide total volume by bag yield (fixed assumptions shown above). Always check your brand datasheet.
How to use this calculator
- Select Imperial or Metric units.
- Click Add line; choose a shape (Slab, Wall, Beam/Footing, Column/Tube, Post Hole, or Stairs) and enter dimensions in the indicated units.
- Set a quantity for repeated shapes.
- Adjust the waste percentage to cover trench over‑dig, spillage, and tolerances.
- Review the totals in yd³ / ft³ / m³ and approximate bag counts.
- Use Download CSV or Download PDF to export line items and totals for your records.
FAQs
Bag yields vary by brand and mix. We use common approximations (80‑lb≈0.60 ft³, 60‑lb≈0.45 ft³, 50‑lb≈0.375 ft³, 25‑kg≈0.011 m³). Always confirm with the manufacturer’s datasheet and add a sensible waste margin.
This tool computes concrete volume only. Base, compaction, reinforcement, and formwork are separate. For trenches or irregular excavations, consider adding extra waste or modeling as additional rectangular volumes.
Pick one unit system at a time. The calculator converts internally and shows totals across yd³, ft³, and m³ for easy comparison.
Typical values range from 5–10% for precise forms to 10–15% for trenches or rough sites. Increase waste if subgrade is soft or excavation tolerances are wide.
Ready‑mix trucks commonly carry about 9–10 yd³ (≈6.9–7.6 m³). Compare your waste‑included total to available truck sizes and discuss split loads with your supplier.
Yes. Edit the yield assumptions in the small config object in the source (look for bagYields) to match your local brand, or simply rely on truck volumes.
Example data table
These example line items match the “Load example” button and illustrate typical residential pours.
| Shape | Dimensions | Qty | Volume (yd³) | Volume (m³) |
|---|---|---|---|---|
| Slab | 20 ft × 12 ft × 4 in | 1 | 2.96 | 2.26 |
| Wall | 30 ft × 8 ft × 6 in | 1 | 4.44 | 3.40 |
| Column | Ø12 in × 10 ft | 2 | 1.31 | 1.00 |
| Post Hole | Ø10 in × 3 ft | 6 | 0.36 | 0.28 |
Assumptions & configuration
Adjust if your local materials differ. These affect only bag estimates and exports.
Reference: quick conversions
- 1 yd³ = 27 ft³
- 1 m³ ≈ 35.3147 ft³
- 1 ft = 12 in
- 1 m = 100 cm
Always verify plans, site conditions, and any structural specifications with a qualified professional.