Concrete Volume Calculator
Use this general concrete-volume tool for rectangular placements; the slab calculator separately owns uniform slab area and material-cost planning.
Compare up to three scenarios
Capture the current result, change one or more inputs, and see the options side by side. The first option becomes your baseline.
Your live calculator remains unchanged. Capture it only when you want a comparison point.
Save this estimate as a project section
Name rooms, roof planes, yard areas or other sections separately. CalcurHome will combine compatible results from this calculator on this device.
No account or personal information required. Data remains in this browser until you delete it or clear browser storage.
View all saved project estimatesWhat does the concrete calculator calculate?
For any rectangular concrete placement, multiply length by width by thickness in feet, divide cubic feet by 27, and add a placement allowance. This page covers general volume and ready-mix quantity. Use the Concrete Slab Calculator when a uniform slab also needs surface-area or material-cost output.
Concrete volume for a rectangular pour
The dimensions produce placed cubic feet after thickness is converted to feet. Dividing by 27 gives cubic yards, and the selected allowance is added to reduce the chance of a short pour.
How to measure for an accurate estimate
- Measure inside the forms rather than using the excavation’s outside dimensions.
- Check thickness at several points because an uneven subgrade increases real concrete volume.
- Calculate thickened edges, grade beams, steps, and footings as separate shapes.
- Use finished dimensions from approved plans for structural work instead of estimating by eye.
General rectangular concrete placement
A rectangular pour is 12 ft long, 10 ft wide, and 4 inches thick with 10% extra.
12 × 10 × (4 ÷ 12) ÷ 27 = 1.48 cu yd exact; order estimate = 1.63 cu yd.Before you purchase material
- Ask ready-mix suppliers about minimum loads, short-load fees, delivery windows, and washout rules.
- Confirm strength, slump, aggregate, air entrainment, and admixtures with the project specification.
- Use bags only when mixing capacity and placement time allow a continuous, properly finished pour.
- Arrange labor, tools, access, weather protection, and curing materials before the truck arrives.
Common questions
How much extra concrete should I order?
Five to ten percent is a common planning range for simple formed work, but irregular excavation or uncertain subgrade can require more. Measure carefully and ask the supplier or contractor; excess concrete also needs a lawful disposal plan.
How many 80-pound bags equal one cubic yard?
At a typical listed yield of 0.60 cubic foot per 80-pound bag, one cubic yard requires 45 bags because 27 ÷ 0.60 = 45. Product yields vary, so the package label controls your final count.
When should I use the Concrete Slab Calculator?
Use the slab-specific calculator when you need uniform slab surface area, order volume, and a material subtotal from a local per-yard quote. Use this general page for rectangular concrete volume without making the page responsible for slab pricing or design.
Can I calculate concrete for multiple sections together?
Yes. Calculate the exact cubic yards of each distinct slab, footing, step, or thickened edge, then add those exact volumes. Apply the placement allowance once to the combined total to avoid compounding waste percentages.
Sources and reference standards
- QUIKRETE Concrete Mix Product DataManufacturer product data used to cross-check typical bag yields; verify the yield printed on the bag you buy.
- International Code Council — 2024 International Residential CodePrimary model-code source for residential foundations, reinforcement, masonry, and stair safety requirements.
See every citation and the calculators that use it in the calculator source index.
Use this result in a complete project plan
Concrete patio planner
A patio estimate becomes useful only when the finished outline, slab thickness, base preparation and concrete purchase method are treated as separate decisions. This guide keeps those decisions in order and shows which number should move from one calculator to the next.
Did this calculator help you make the next project decision?