How Much Soil for a 4×8 Raised Bed?
The 4×8 raised bed is the most popular size in North American gardens. At the standard 12-inch depth, it requires exactly 32 cubic feet of soil — about 1.19 cubic yards or 906 liters. You'd need 32 one-cubic-foot bags or 16 two-cubic-foot bags. Going deeper to 18 inches takes 48 cubic feet; 24 inches takes 64. The calculator above is pre-filled for a 4×8 at 12 inches — adjust the depth to suit your build.
How to Use This Calculator
Select your bed shape (Rectangle, Square, or Circle), choose your unit of measurement, then enter your dimensions. For rectangular and square beds, enter length, width, and depth. For circular beds, enter the diameter and depth. Click Calculate Soil Needed to see your results instantly in cubic feet, cubic yards, liters, and gallons — plus bag counts for all four standard bag sizes.
Understanding Your Results
Cubic feet is the unit printed on most bagged soil at garden centers. Use this number to count bags. Cubic yards is the unit used by landscape bulk suppliers — divide cubic feet by 27 to get cubic yards. Liters is the metric equivalent (1 cu ft = 28.32 liters). Gallons is helpful for smaller container calculations (1 cu ft = 7.48 gallons).
Soil Mix Recommendation
The best all-purpose raised bed mix is 60% quality topsoil, 30% compost, and 10% perlite or coarse sand. This blend drains well, retains moisture, and provides the nutrients plants need. Avoid filling raised beds with pure topsoil — it compacts and restricts root growth. Always include at least 25–30% organic matter.