How much potting soil do I need? Use our calculation!

Calculate how much potting soil you need for your flowerpot, fibreglass planter or border. If you calculate the soil beforehand you avoid having not enough potting soil or having too much. Here we explain how you can calculate how much potting soil you need for a square, rectangular or a round planter.

In a square or rectangular planter you calculate the amount as follows

Length in centimetres x width in centimetres x height in centimetres and divide this by 800.

For example if the planter is 30 centimetres wide, 30 centimetres high and 30 centimetres long, then the calculation is: 30 x 30 x 30. The total is then 27000. Divide this by 800. And you will need 34 litres of potting soil. If you buy potting soil in bags of ten litres, it will be wise to round up the number of litres. You will have a bit of potting soil left, but you can probably use this for another planter.

To make it easy for you, we have listed the most popular dimensions:

  • 230 x 050 x 040 cm = 575 litres
  • 208 x 030 x 020 cm = 156 litres
  • 200 x 040 x 040 cm = 400 litres
  • 180 x 088 x 032 cm = 637 litres
  • 120 x 120 x 040 cm = 720 litres
  • 120 x 040 x 040 cm = 240 litres
  • 120 x 030 x 060 cm = 270 litres
  • 120 x 030 x 040 cm = 180 litres
  • 100 x 100 x 060 cm = 750 litres
  • 100 x 100 x 040 cm = 500 litres
  • 100 x 040 x 040 cm = 200 litres
  • 090 x 025 x 080 cm = 225 litres
  • 060 x 060 x 060 cm = 270 litres
  • 060 x 060 x 040 cm = 180 litres
  • 050 x 050 x 050 cm = 156 litres
  • 040 x 040 x 080 cm = 160 litres

The calculation formula also works for smaller flower pots

  • 40 x 40 x 40 cm = 80 litres
  • 35 x 35 x 35 cm = 54 litres
  • 30 x 30 x 30 cm = 34 litres
  • 25 x 25 x 25 cm = 20 litres
  • 20 x 20 x 20 cm = 10 litres
  • 15 x 15 x 15 cm = 4 litres
  • 10 x 10 x 10 cm = 1,25 litres
  • 05 x 05 x 05 cm = 0,16 litres

How to calculate potting soil for a round planter?

The calculation for a round planter is slightly different. Instead of the length and the width, you use the diameter of the flowerpot. For example the planter has a diameter of 30 centimetres and it is 26 centimetres high, then the calculation is as follows: 30 x 30 x 26 cm / 1800 = 13 litres.

In short, you multiply the diameter by the diameter and then you multiply this by the height. You then divide this by 1800.

To make it easy for you, we have listed the most popular dimensions:

  • ø 120 x 80 cm high = 640 litres
  • ø 100 x 80 cm high = 444 litres
  • ø 100 x 60 cm high = 333 litres
  • ø 80 x 80 cm high = 284 litres
  • ø 80 x 60 cm high = 213 litres
  • ø 60 x 80 cm high = 160 litres

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