How to calculate soil for raised garden bed
1. Measure the inside footprint
Boards can be thick. The inside width is what the soil actually fills.
2. Use the finished soil depth
Do not use the board height if you leave a mulch gap at the top.
3. Convert to bag size
Most bags are sold in cubic feet. Bulk yards help once the bed count grows.
4. Add a little settling margin
Fresh soil drops after watering, especially in new beds with compost-heavy blends.