๐ชด Plant Pot Soil Volume Calculator
This calculation assumes a cylindrical pot.
Enter a cylindrical plant pot's diameter and depth (height) to estimate how much potting soil, in liters, you'll need.
How to use
- Enter the pot's diameter (cm).
- Enter the pot's depth/height (cm).
- The required soil volume is calculated automatically.
How the calculation works
Calculate how much soil (in litres) a round plant pot holds from its diameter and depth, so you know how much potting mix to buy when repotting. Capacity (L) = ฯ ร (diameter รท 2)ยฒ ร depth รท 1000 The pot is treated as a cylinder. Measure the inside diameter at the rim and the inside depth.
Worked example
A 15 cm pot, 14 cm deep โ about 2.5 L A 30 cm pot, 25 cm deep โ about 17.7 L In Japan, pot sizes are given as gล, where 1 gล is about 3 cm of diameter (size 5 โ 15 cm). Potting mix often comes in 5, 14 or 25 L bags, so choose a bag a little larger than you need.
Things to be aware of
- Most pots taper towards the base, so they usually hold 10โ20% less than calculated.
- Subtract space for drainage stones at the bottom and for a 2โ3 cm gap below the rim for watering.
- For square planters, use length ร width ร depth รท 1000.
FAQ
What formula does this use?
It uses the cylinder volume formula "V = ฯ ร radiusยฒ ร height", converting cmยณ to liters by dividing by 1000.
Will the actual amount of soil needed differ?
Since this doesn't account for the pot's exact shape (e.g. tapering toward the base) or drainage material, the actual amount needed may be somewhat less. Treat this as an estimate.
Can this be used for square or rectangular pots?
This tool assumes a cylindrical (round) pot. For a rectangular pot, calculate the volume directly as length ร width ร height.