How Much Soil Is Needed for a Raised Garden Bed?

The soil needed for a raised garden bed is calculated by multiplying length by width by depth (all in feet). Convert to cubic feet for bag shopping or cubic yards for bulk orders. …

All Shapes Supported Inches, Feet, CM & Meters Bag Count & Cost Estimate

Calculate Your Soil

Enter your raised bed dimensions below

Bed Shape
Measurement Units
Bag Size & Cost Options Optional

How Much Soil Is Needed for a Raised Garden Bed?

The soil needed for a raised garden bed is calculated by multiplying length by width by depth (all in feet). Convert to cubic feet for bag shopping or cubic yards for bulk orders. This calculator does all of that automatically and also outputs liters, gallons, and bag counts for all standard sizes in a single calculation — no manual math required.

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).

Volume Formula (Rectangle)
Volume = Length × Width × Depth (all in feet)

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.

💡 Order 10% extra: Soil settles 10–15% after the first thorough watering. Buying a little extra prevents a second trip to the store.
Common Questions

Frequently Asked Questions

A 4×8 foot raised bed at the standard 12-inch depth requires 32 cubic feet of soil — about 1.19 cubic yards. You would need 32 one-cubic-foot bags or 16 two-cubic-foot bags. At an 18-inch depth you need 48 cubic feet, and at 24 inches you need 64 cubic feet. Use the calculator above to adjust for your specific depth.
The most versatile depth is 12 inches, which suits most vegetables and flowers. For deep-rooted plants like tomatoes and carrots, 18–24 inches is better. For shallow-rooted herbs and lettuce, 6–8 inches is enough. When in doubt, build to 12 inches — it is the best all-purpose choice.
For beds under 20 cubic feet (roughly one or two small beds), bagged soil is most convenient. For projects over 2 cubic yards (54 cubic feet), bulk soil delivered by a landscape supplier is typically 40–60% cheaper. Use the cubic yard output from this calculator to compare bulk pricing against bag totals.
Filling a standard 4×8 bed at 12 inches deep (32 cubic feet) typically costs $100–$350 depending on soil quality. Budget bagged soil: roughly $100–$160. Premium bagged mix: $200–$350. Bulk delivery: $80–$150. Enter your price per bag into the cost section of the calculator above for an exact estimate.
For irregular shapes, break the bed into simple geometric sections (rectangles or triangles), calculate the volume of each section separately using this calculator, and add the totals together. For circles, select the Circle tab above and enter the diameter and depth. Most raised beds are rectangular — the Rectangle tab handles those perfectly.