Soil Bag Estimator for Raised Garden Beds

This soil bag estimator shows results for all four standard bag sizes at once so you can compare options at a glance. Enter your bed dimensions, click Calculate, and instantly see …

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

Soil Bag Estimator for Raised Garden Beds

This soil bag estimator shows results for all four standard bag sizes at once so you can compare options at a glance. Enter your bed dimensions, click Calculate, and instantly see how many 0.5, 1, 1.5, and 2 cubic foot bags you need. The calculator always rounds up to the nearest whole bag so you never run short mid-project.

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.
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.
The best all-purpose raised bed mix is: 60% topsoil, 30% compost, 10% perlite or coarse sand. For a premium option, try Mel's Mix: equal thirds of compost, peat moss (or coco coir), and coarse vermiculite. Avoid filling beds with pure topsoil — it compacts and drains poorly in a raised environment.
Native garden soil on its own is not recommended for raised beds — it tends to compact heavily, restricts root growth, and drains poorly. If you want to incorporate native soil, use no more than 40% mixed with compost and a drainage amendment like perlite or coarse sand.
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.