Concrete calculator.
Calculate concrete in cubic yards or cubic metres for one pour or several sections. Add your allowance and supplier order increment.
Your dimensions
Measurement schematic, not to scale. Use your own dimensions and product specification.
Use measurements from your plan and properties from your chosen product. Any prefilled values are illustrative.
Concrete Calculator Concrete to order: 8.15 yd³ Net pour area: 600 ft² Calculated volume: 7.41 yd³ Waste allowance: 0.74 yd³ Supplier rounding surplus: 0 yd³ Inputs Measure: One rectangular section Length: 20 ft Width: 30 ft Thickness: 4 in Waste allowance: 10 % Area to exclude: 0 ft² Supplier volume order increment: 0 yd³ Formula: Order = round up(Σ(net area × thickness × count) × (1 + allowance) ÷ increment) × increment Assumptions: Calculate each non-overlapping section from your specified footprint and thickness, add their volumes, and apply the allowance once to the combined pour. If a supplier order increment is entered, round the combined volume up once. A zero increment returns the unrounded requirement. This calculator does not choose slab thickness, reinforcement or a concrete mix. Only quantities from supplied dimensions and specifications are calculated. No material-property reference values are bundled; obtain product values from the selected supplier's data sheet. Dimensions come from your plan. Confirm order increments and the specification with your supplier. Based on supplied measurements and specifications. No design suitability or code compliance is assessed.
Concrete to order
Example estimate · update the inputs for your project
How this result becomes a purchase quantity
These are the actual stages returned by this calculation. Stages with the same quantity and unit are shown once. Additional stages are not invented.
- Concrete to order: 8.15 yd³
- Calculated volume: 7.41 yd³
- Net pour area: 600 ft²
- Waste allowance: 0.74 yd³
- Supplier rounding surplus: 0 yd³
Order = round up(Σ(net area × thickness × count) × (1 + allowance) ÷ increment) × increment
Calculate each non-overlapping section from your specified footprint and thickness, add their volumes, and apply the allowance once to the combined pour. If a supplier order increment is entered, round the combined volume up once. A zero increment returns the unrounded requirement. This calculator does not choose slab thickness, reinforcement or a concrete mix.
Order 8.15 yd³From your calculated quantity.
Dimensions come from your plan. Confirm order increments and the specification with your supplier.
How to use this concrete calculator
Use this concrete yard calculator for the specified volume of your pour. One combined order can include several footprints and thicknesses; the tool keeps geometric volume, allowance and supplier rounding separate.
- For one rectangular pour, enter length, width and the thickness specified in your plan.
- For several pours, select several sections. Add each non-overlapping rectangle, circle, triangle or known area with its own thickness and count.
- Enter any cut-outs within their section. Add the allowance you have chosen for the combined order.
- If the supplier sells in fixed volume increments, enter that increment. Leave it at zero to get the unrounded requirement.
Formula and assumptions
How this calculation works.
Calculate each non-overlapping section from your specified footprint and thickness, add their volumes, and apply the allowance once to the combined pour. If a supplier order increment is entered, round the combined volume up once. A zero increment returns the unrounded requirement. This calculator does not choose slab thickness, reinforcement or a concrete mix.
A worked example
Illustrative inputs only. Product properties and design dimensions are not recommendations for your project.
- Measure
- One rectangular section
- Length
- 4 m
- Width
- 5 m
- Thickness
- 100 mm
- Waste allowance
- 10 %
- Area to exclude
- 0 m²
- Supplier volume order increment
- 0 m³
Concrete to order: 2.2 m³
Dimensions come from your plan. Confirm order increments and the specification with your supplier.
Measured volume is not necessarily the supplier’s order quantity
Use your supplied slab dimensions and subtract only measured uncovered areas. A supplier’s delivery increment can round an order upward separately from your own allowance.
- Confirm that all thickness values come from your supplied plan; this tool does not choose slab thickness.
- Keep deductions, allowance and supplier rounding separate. Do not apply the same allowance again when converting to bags.
- Bag weight is not yield. Use the selected mix’s stated prepared volume per bag.
What changes when one measurement changes?
Using the worked example above, change only thickness from 100 to 150mm. Product specifications and all other inputs stay the same.
Concrete to order: 2.2 → 3.3m³
Both results are computed by the same current calculator engine. These are illustrative dimensions, not material or design recommendations.
Calculation version and responsibility
Formula version: 2. Input schema: 2. Output schema: 2. Material data: user-supplied. Safety text: 1.
The method uses your dimensions and supplied product properties. Software tests check arithmetic examples and validation; this does not establish professional review of a design. Read the calculation policy.
Before you purchase
Use dimensions from your plan and properties from your chosen product. Any design spacing, section or fixing pattern must already be specified.
Sections must not overlap. Excluded area is deducted within each section before multiplying by thickness or counting identical sections.
Method: dimensional arithmetic and user-supplied specifications. Software checks: 2026-10-04. Calculation and review policy.
A US unit example
A 10 ft × 20 ft pour at a specified 4 in thickness has a geometric volume of 200 × (4 ÷ 12) ÷ 27 = 2.4691 yd³. An illustrative 10% allowance gives 2.7160 yd³. An entered 0.25 yd³ supplier increment rounds the combined order to 2.75 yd³. These dimensions and allowance illustrate arithmetic; they are not design recommendations.
Common questions
Is a concrete yard calculator different from a concrete volume calculator?
They solve the same volume task. This page returns cubic yards in US mode and cubic metres in metric mode, so a second calculator page is unnecessary.
How do I turn cubic yards into concrete bags?
Use the Concrete Bag Calculator with the mixed yield from your selected product label. Bag weight alone does not specify yield. If the volume already includes an allowance, enter zero additional allowance in the bag tool.
Does this select the correct slab thickness?
Thickness is an input from your plan. The result is a material quantity, with no structural, reinforcement or mix-design assessment.