How this estimate works
The calculator applies: ceil(length x width x depth x (1 + waste/100) / bagVolume). Keep measurements in one unit system and round up when suppliers sell whole units.
Limitations
Settling, irregular shapes, compost ratio, and drainage layers may alter required volume.
Source to check
Read the authoritative guidance for garden soil calculator
Frequently asked question
Should I fill to the rim? Leave the headspace recommended for watering and settling.