How do I calculate soil needed for a garden?

Measure the Length, Width, and Depth of your garden bed. Multiply them together (L x W x D) to get the volume. Use our Soil Calculator to convert this instantly into bags or cubic yards.

What kind of soil do I need for raised beds?

For raised beds, use a mix of topsoil, compost, and potting mix. Avoid using 100% garden soil from the ground as it can compact too densely and drain poorly.

Soil Calculator: Calculate Dirt for Raised Beds & Gardens

Professional gardener measuring flower beds

Calculating the exact amount of soil for your garden project can be tricky. Buying too little halts your progress, while buying too much is a waste of money. Our free Soil Calculator helps you determine the precise volume of topsoil, potting mix, or compost needed for raised beds, planters, and landscaping projects.

Pro Tip: Account for Compression

Soil settles and compresses after watering. A good rule of thumb is to add 10% to your calculation to account for settling. If our calculator estimates you need 10 bags, buy 11 to be safe!

Buying Guide: Bagged Soil vs. Bulk Soil

Should you drive to the garden center for bags or order a truckload delivery? Here is a quick comparison:

Feature	Bagged Soil	Bulk Soil (Delivery)
Best For	Small projects, pots, < 1 cubic yard	Large gardens, > 2 cubic yards
Cost	Higher per cubic foot	Cheaper in large volume
Convenience	Easy to carry, clean	Messy, dumped on driveway

Common Raised Bed Sizes & Soil Needs

If you are building a standard raised bed, here are the quick estimates (assuming 10-inch depth):

3D dimensioning diagram of a standard 4x8 flower bed

4′ x 4′ Bed: Requires ~13.5 cubic feet (~0.5 cubic yards).
4′ x 8′ Bed: Requires ~27 cubic feet (~1 cubic yard).
2′ x 6′ Planter: Requires ~10 cubic feet.

Soil Formulas: The Math Behind the Tool

Our tool does the heavy lifting, but the math behind it is simple geometry. You can verify the results using these formulas:

1. Rectangular Garden Beds

Multiply the three dimensions to get the cubic volume.

        Volume = Length × Width × Depth
    

2. Round Pots (Cylinders)

Calculate the area of the circle and multiply by depth.

        Volume = π × (Radius)² × Depth
    

Frequently Asked Questions

How many bags of soil make a cubic yard?

There are 27 cubic feet in one cubic yard. If you are buying standard 1 cubic foot bags, you will need 27 bags. If you are buying larger 1.5 cubic foot bags, you will need 18 bags.

What is the best soil mix for raised beds?

The ideal mix for raised beds is often called “Mel’s Mix”: 1/3 blended compost, 1/3 peat moss (or coconut coir), and 1/3 coarse vermiculite. This ensures excellent drainage while retaining moisture.

How deep should soil be for vegetables?

Leafy greens (lettuce, spinach) only need 6 inches. Most vegetables (tomatoes, peppers, beans) thrive in 12 inches of soil. Deep root vegetables like carrots usually require 12-18 inches.

Disclaimer: This calculator provides an estimate. Soil density and moisture can vary. We recommend verifying specific product coverage with the manufacturer.

Soil Calculator

Q: How many bags of soil make a cubic yard?

There are 27 cubic feet in one cubic yard. If you are buying standard 1 cubic foot bags, you will need 27 bags.

Estimate the perfect amount of soil for your project.

Choose Plant Type

General Purpose

Vegetables / Herbs

Flowers

Succulents / Cacti

Lawn / Grass

Trees / Shrubs

Recommended Soil All-Purpose Potting Mix or Garden Soil.

Shape

Length

Width

Diameter

Depth

Bag Size (Estimation)

Total Volume 0 Liters

Cubic Yards 0 yd³

Cubic Feet 0 ft³

Bags to Buy 0

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