# Calculate precast concrete - this is how it works

If you want to pour a specific concrete surface, you have to estimate how many bags of ready-mixed concrete you will need. This can be tricky at times. Read here how you can best get around and what to look out for.

## Calculate volume

First of all, you need to calculate the volume of the concrete surface that you want to pour. To do this, just take the width of the area and multiply it by the length of the area. Always use meters as the unit for the calculation - 1 cm corresponds to 0.01 m. Then multiply the result by the height of the desired concrete layer, also in meters. You will then receive the volume in m³ (m x m x m)

• Also read - precast concrete or mix it yourself?
• Also read - correctly process precast concrete
• Also read - The prices of precast concrete

## Determination of the concrete requirement

Then it gets more complicated. For example, you need 0.6 m³ of concrete for your project. To determine how many bags of ready-mixed concrete (€ 15.69 on Amazon *) you need for it, you either have to estimate the yield well or do a lot of math. The volume that a bag of ready-mixed concrete produces depends on:

• the degree of compaction of the concrete when pouring a foundation, for example
• partly also from the grain and of course
• from the addition of water
• the degree of shrinkage of the concrete in question when it hardens

If it is not stated on the concrete bag how many m³ of concrete results from mixing and how many m³ after it has hardened, you definitely have to do the math. To do this, use the dry density of the concrete and take into account the addition of water accordingly.

Tips & Tricks The calculation is easier for mixing the concrete yourself, there are certain formulas.

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