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Concrete Volume Calculator

Use this concrete volume calculator entirely in your browser.

ResultConcrete volume: 3.150 m³

Measured volume before allowance: 3.000 m³

Waste allowance: 5.00%

Equivalent volume: 4.120 yd³

Order quantities, batching, compaction, spillage, reinforcement, and supplier practices may require a different allowance.

Calculations happen locally in your browser.

How to use this calculator

  1. Enter the labelled values and review the live result.
  2. Review the live result and use Copy result when you need to share it.

How the calculation works

Length and width are multiplied by depth converted from millimetres to metres, then the entered waste allowance is applied.

Formula

Volume = length × width × (depth ÷ 1,000) × (1 + waste percentage ÷ 100)

Step-by-step calculation

  1. Enter the labelled values and review the live result.
  2. Length and width are multiplied by depth converted from millimetres to metres, then the entered waste allowance is applied.
  3. Check the displayed result, then copy it if needed.

Worked example

A 6 m by 4 m slab at 125 mm depth is 3.000 m³ before a waste allowance.

Risk guidance

Rectangular volume and allowance

The calculator models one rectangular pour. Depth is converted from millimetres to metres before multiplying by length and width, and the selected percentage is added only as a planning allowance.

Why ordered quantity may differ

Excavation variation, sub-base levels, form movement, spillage, pumping, compaction, reinforcement displacement, supplier batching, and minimum-order rules can change the quantity required. Confirm the order with the designer, contractor, and supplier.

Not a structural design tool

Volume does not select concrete strength, exposure class, reinforcement, thickness, joints, foundation dimensions, drainage, curing, or load capacity. Those decisions require the applicable design information and qualified review.

Frequently asked questions

Is the waste allowance a recommendation?

No. It is a user-selected planning allowance. Site conditions, supplier practices, and the work specification determine the appropriate ordered quantity.

Can this design a slab or foundation?

No. It estimates rectangular volume only and does not determine thickness, strength, reinforcement, support, joints, drainage, or structural capacity.

Does this tool send my inputs anywhere?

No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.

How should I use the result?

Use it for early planning only. Verify measurements, definitions, current local requirements, and the complete design with the relevant authority and appropriately qualified professionals.

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