Raised Bed Soil Calculator

Figuring out exactly how much soil a raised bed needs means you buy what the bed takes and leave the waste behind. Alongside the volume, the tool suggests mix proportions tuned for healthy, productive plant growth.

Volume comes first, calculated as Length (feet) x Width (feet) x Depth (feet) = Total Volume (cubic feet). The calculator uses that raw figure with no allowance for settling, so plan to top the bed up once the soil settles. It also converts the volume to cubic yards (divide by 27), to 1.5-cubic-foot bags rounded up, and to a cost range at a fixed $3 to $5 per cubic foot, a planning figure rather than a quoted price. For the mix itself, the recommended ratio is 60% topsoil, 30% compost, and 10% perlite/vermiculite, a blend known for strong drainage paired with good nutrient retention.

Accurate measurements pay off here, because a small error in length, width, or depth snowballs into ordering far too much or too little soil. Bagged volumes can mislead since compaction varies from bag to bag, so buying in bulk often gives better value and more consistency. One detail that's easy to overlook: any existing drainage layer takes up space and trims the actual soil volume you'll need.