Top-Dressing a 4×8 ft Raised Bed with 6 Inches of Compost
Calculate the cubic yards of compost needed to add a 6-inch layer on top of a 4 ft × 8 ft raised bed.
How to use this tool
- Enter the inside dimensions of your raised bed in feet.
- Enter the depth of soil you need to fill in inches (10–12 in is standard).
- The calculator returns cubic feet, cubic yards, and the number of 40-litre bags to buy.
Adding a fresh layer of compost each season? This calculator shows how much material you need to top-dress a 4×8 foot bed 6 inches deep.
Frequently asked questions
- How much soil do I need for a raised bed?
- Multiply the inside length × width (ft²) by the fill depth in feet (inches ÷ 12). A 4×8 ft bed filled 12 inches deep needs 32 cubic feet of soil.
- What soil mix is best for raised beds?
- A popular recipe is the Mel's Mix: 1/3 compost, 1/3 peat moss or coir, and 1/3 coarse vermiculite. This provides excellent drainage and nutrient retention.