Concrete calculator

Rectangular concrete volume = length × width × depth. Apply your allowance, then divide by bag yield and round up if buying bags.

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Length (m)

Width (m)

More inputs and assumptions

Depth (m)

Extra allowance (%)

Yield per bag (m³)

Answer

…

Rectangular concrete volume = length × width × depth. Apply your allowance, then divide by bag yield and round up if buying bags.

More results

Precision and calculation record

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Formula and assumptions

Bag yield is a user-entered example, not a product claim. Check the product label. This estimates quantity only, not mix design, strength, reinforcement or structural suitability.

Automatic precision shows numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

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Updated 2026-09-26

Using Concrete calculator

Rectangular concrete volume = length × width × depth. Apply your allowance, then divide by bag yield and round up if buying bags.

Bag yield is a user-entered example, not a product claim. Check the product label. This estimates quantity only, not mix design, strength, reinforcement or structural suitability.

Next: Volume calculator

A worked example

With length (m) = 4, width (m) = 3, depth (m) = 0.1, extra allowance (%) = 10, yield per bag (m³) = 0.015, the concrete volume (m³) is 1.32.

Next: Post hole concrete calculator

Before you use the result

Bag yield is a user-entered example, not a product claim. Check the product label. This estimates quantity only, not mix design, strength, reinforcement or structural suitability.

Example results for length (m)

These examples use Width (m): 3; Depth (m): 0.1; Extra allowance (%): 10; Yield per bag (m³): 0.015. They are reference calculations, not recommended settings.

Length (m)	Concrete volume (m³)
2	0.66
4	1.32
8	2.64

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