Raised Bed Soil Calculator
Estimate how much soil you need for a rectangular raised garden bed.
Enter positive dimensions. Changing measurement units converts your current measurements rather than resetting them.
Estimates are for rectangular areas. Check bag sizes and specifications with your supplier.
How to use this calculator
Measure the inside length, width and fill depth of the bed. Account for any existing soil or filler that reduces the volume you need.
Worked example
A 4 ft × 8 ft raised bed filled 12 inches deep requires 32 cubic feet, or about 1.19 cubic yards. That is 16 bags of 2 cubic feet each.
Example: a 4 × 8 ft raised bed
For a 4 × 8 ft bed filled to a depth of 12 inches, the volume is 32 cubic feet, about 1.19 cubic yards. With 2 cubic-foot bags, that is 16 bags before settling.
Calculation method
Volume = length × width × depth, converted to matching units. One cubic yard is 27 cubic feet. Bags are rounded up to a whole bag.
Planning tip
Soil can settle after watering. Soil blends and packaging volumes vary; consult your supplier before purchasing.
Frequently asked questions
Can I use metric measurements?
Yes. Select meters and centimeters from the measurement units menu. The results include cubic meters as well as US units.
Is this an exact purchase quantity?
No. It is a planning estimate. Irregular shapes, settling, compaction and supplier packaging can change the amount needed.
Plan soil for a raised garden bed
Measure the inside dimensions
Use the usable inside length and width, not the outside dimensions of thick timber or masonry walls. Measure the fill depth from the bottom of the bed to the desired soil surface.
Leave room below the rim
A raised bed is often not filled flush to the very top. Decide how much room you want to leave for watering and mulch, then enter the actual soil depth in the calculator.
Example: a 4 × 8 ft raised bed
A bed with inside dimensions of 4 × 8 ft and 12 inches of soil requires 32 ft³, about 1.19 yd³. That equals 16 bags of 2 ft³ each before any allowance for settling.
Soil mixes and settling
Bagged products can have different volumes and compositions. Soil may settle after watering. Ask your supplier about suitable mixes for your plants and whether extra material is recommended.
Several beds?
Calculate each bed separately, then add the cubic-foot results before converting to bags. This avoids rounding up each small bed independently and potentially buying unnecessary bags.
Explore the other free tools: Mulch calculator, Gravel calculator, and Raised bed soil calculator.