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Estimate concrete volume for a rectangular pour, including a waste allowance you choose.
Results update as you type. No calculate button. All calculations run locally in your browser.
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Bars are scaled to the larger of the two volumes. The waste slice is the extra you order on top of the exact rectangular volume.
| Waste allowance | Value |
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Same length, width and depth; only the waste allowance changes. Use this to see how sensitive the order is to the allowance you pick.
Net volume = length × width × depth. Waste volume = net volume × waste rate. Order volume = net volume × (1 + waste rate).
Length 10 m, width 4 m, depth 0.15 m: net volume = 10 × 4 × 0.15 = 6 m³. At an 8% waste allowance, waste volume = 6.00 × 0.08 = 0.48 m³, so order volume = 6.48 m³ (228.84 ft³). These are the example defaults above; replace them with your own measurements.
This covers a single rectangular pour only. Subgrade variation, reinforcement displacement, irregular shapes, sloped sections, supplier minimum loads and rounding to the supplier's ordering unit can all change the order. No price is calculated: enter no price here, so compare supplier quotes against the order volume yourself.
Because a real pour rarely matches the exact rectangular volume: spillage, uneven subgrade and formwork gaps all consume extra concrete. The allowance is your buffer, not a supplier charge.
Split it into measured rectangles, calculate each one, and add the net volumes before applying waste. Do not force an irregular shape into one rectangle and hope the waste allowance absorbs the difference.
Measure the finished slab thickness at several points and use a representative value. If depth varies a lot, split the pour into zones with different depths instead of averaging blindly.
No. If your order is below a supplier minimum, the supplier may still charge for the minimum. Check that before ordering, especially for small pours.
Yes: 1 m³ = 35.3147 ft³ = 1,000 litres. The breakdown table shows the order in all three units.
No, there is no price input on this page. Multiply the order volume by your supplier's quoted price per unit yourself; prices vary by mix, location and delivery terms.
Results are estimates only and do not constitute professional advice.