CalculationTime

Concrete Volume Calculator

Live math canvas

Your numbers, formula and explanation together

Concrete Volume Calculator: 117 cubic metres. Concrete Volume Calculator uses the declared inputs to produce a transparent default result. Length: 4 m; Width: 3 m; Depth: 100 mm; Waste allowance: 10 %; primary comparison: 4 and 3.

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Depth in metres = depth millimetres ÷ 1,000. Base volume = length × width × depth. Concrete with allowance = base volume × (1 + waste percent ÷ 100).
  1. Apply the formulaDepth in metres = depth millimetres ÷ 1,000. Base volume = length × width × depth. Concrete with allowance = base volume × (1 + waste percent ÷ 100).117 cubic metresConcrete Volume Calculator uses the declared inputs to produce a transparent default result. Length: 4 m; Width: 3 m; Depth: 100 mm; Waste allowance: 10 %; primary comparison: 4 and 3.

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Length
4 m
Measure the planned pour length in metres.
Width
3 m
Measure the planned pour width in metres.
Depth
100 mm
Enter slab or footing depth in millimetres.
Waste allowance
10 %
Optional allowance for uneven ground, spillage, over-excavation and ordering tolerance.

Resulting answer

117 cubic metres

Concrete Volume Calculator uses the declared inputs to produce a transparent default result. Length: 4 m; Width: 3 m; Depth: 100 mm; Waste allowance: 10 %; primary comparison: 4 and 3.

Answer
117 cubic metres
Live support
Concrete Volume Calculator uses the declared inputs to produce a transparent default result. Length: 4 m; Width: 3 m; Depth: 100 mm; Waste allowance: 10 %; primary comparison: 4 and 3.

Assumptions used

What this answer assumes

Volume estimate only. Confirm mix, delivery minimums and structural requirements before ordering.

  • Length and width are entered in metres and depth is entered in millimetres.
  • The pour is treated as a rectangular prism with a consistent average depth.
  • Waste allowance is a planning input only; it is not a building-code, engineering or supplier standard.
  • The result does not check reinforcement, sub-base preparation, slump, strength grade, delivery minimums or structural design requirements.

Master’s Tip

How to use the result well

Master’s Tip: measure the average finished depth separately from the excavation depth. For real orders, round up after checking site variation, formwork, sub-base level, pump/driver advice, minimum delivery quantities and whether part loads are practical.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Length
4 m
Measure the planned pour length in metres.
Width
3 m
Measure the planned pour width in metres.
Depth
100 mm
Enter slab or footing depth in millimetres.
Waste allowance
10 %
Optional allowance for uneven ground, spillage, over-excavation and ordering tolerance.

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Copy a clean iframe version with the required CalculationTime attribution link built in.

Formula

Depth in metres = depth millimetres ÷ 1,000. Base volume = length × width × depth. Concrete with allowance = base volume × (1 + waste percent ÷ 100).

Worked example

For a 4 m by 3 m slab at 100 mm depth: depth = 100 ÷ 1,000 = 0.10 m. Base volume = 4 × 3 × 0.10 = 1.20 m³. With 10% allowance, 1.20 × 1.10 = 1.32 m³.

Professional note

Master’s Tip: measure the average finished depth separately from the excavation depth. For real orders, round up after checking site variation, formwork, sub-base level, pump/driver advice, minimum delivery quantities and whether part loads are practical.

Regional and unit assumptions

Standard or basis: this page uses transparent rectangular-volume arithmetic in SI metric units. One cubic metre is the volume of a cube one metre on each side; no concrete strength, mix design or compliance certification is claimed.

Assumptions and limitations

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Depth in metres = depth millimetres ÷ 1,000. Base volume = length × width × depth. Concrete with allowance = base volume × (1 + waste percent ÷ 100).

Standard or basis

Standard or basis: this page uses transparent rectangular-volume arithmetic in SI metric units. One cubic metre is the volume of a cube one metre on each side; no concrete strength, mix design or compliance certification is claimed.

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Master’s Tip: measure the average finished depth separately from the excavation depth. For real orders, round up after checking site variation, formwork, sub-base level, pump/driver advice, minimum delivery quantities and whether part loads are practical.

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These cards are resolved from calculator data, category context and live-route status so the page links to useful next steps without hand-built link clutter.

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Questions

How do I calculate concrete volume?

Convert the depth to metres, then multiply length × width × depth. Add any waste allowance after the base volume is visible.

How many cubic metres are needed for a 4 m by 3 m by 100 mm slab?

The base volume is 4 × 3 × 0.10 = 1.20 cubic metres. With a 10% allowance, the estimate becomes 1.32 cubic metres.

Should I add waste when ordering concrete?

Often yes for planning, but the right allowance depends on site level, excavation accuracy, spillage, delivery method and supplier advice. This page lets you test the percentage separately.

Does this choose the concrete mix strength?

No. It estimates volume only. Strength grade, reinforcement and structural requirements should be checked against the plans, engineer, builder or local code.

Can I use this for footings or trenches?

Yes for rectangular footings and trenches when length, width and average depth are known. Irregular shapes should be split into simpler sections and added together.

Calculation note

Concrete estimating is volume arithmetic before it is a material order. The calculator keeps the measured prism, depth conversion and allowance separate so a slab, footing or trench estimate can be checked line by line.

Concrete volume is a three-dimensional measurement

Area alone is not enough for a concrete pour. A slab needs length, width and depth, and the depth must be converted into the same unit as the other dimensions before volume is calculated.

Allowance belongs after the measured volume

Uneven ground, formwork variation, over-excavation, spillage and delivery handling can make the ordered quantity higher than the neat geometric volume. Keeping the allowance separate makes the assumption visible instead of hiding it in the measurement.

Volume is not structural approval

Knowing cubic metres does not decide concrete strength, reinforcement, curing, control joints or code compliance. Those choices depend on plans, engineering, site conditions and local building requirements.

Sources and further readingNIST: SI Units — LengthBIPM: SI BrochurePortland Cement Association: Concrete basics