Potting soil calculator
Stop overbuying bags of dirt. Calculate exactly many liters or quarts you need to fill your favorite planters.
Roughly 0.3 of a 40L bag.
The "Dead Space" factor
I genuinely don't know why soil volume feels so impossible to guess. Every time I repot a Monstera, I either have half a bag left over that gets spider webs in the garage, or I’m 2 liters short and have to use old soil. This calculator assumes you’re filling the pot to about 1 inch (2.5cm) from the top — you need that "headroom" so the water doesn't spill over when you give your plants a drink.
Note on "tapered" pots: Most round pots get narrower at the bottom. Our math takes this into account by assuming a standard 10-20% taper. If your pot is a perfect cylinder, your count might be slightly low; if it’s extremely tapered, you’ll have a bit left over.
Pro Tip: Don't pack it down
When you're filling the pot, don't press the soil down hard with your thumbs. You'll crush all the air pockets that the roots need to breathe. Just tap the pot on the table to let the soil settle naturally. Our calculator accounts for this "settling."