Raised Bed Soil Calculator

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Walk-through

How to Use This Calculator

4 steps

1

Measure the bed

Measure the inside length, width, and depth of your raised garden bed in feet or inches. Measure depth as how deep you plan to fill it with soil, not the full height of the bed's walls.

2

Enter the dimensions

Type the length, width, and depth into the calculator, and pick feet or inches from the units dropdown. All three fields use the same unit, so keep them consistent.

3

Read the soil volume

The calculator multiplies length by width by depth and shows the result in both cubic feet and cubic yards, updating instantly as you adjust any input.

4

Check bags needed

Enter your bag's coverage in cubic feet from its label, then switch to the Bags Needed tab to see how many bags to buy for a bulk soil order or a bag-by-bag trip.

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Reference

Formula & Methodology

1 formula

Soil volume

volume (ft³) = length × width × depth

Length, width, and depth are converted to feet first (dividing by 12 if entered in inches), then multiplied together to get cubic feet. Cubic yards = cubic feet ÷ 27, since one cubic yard is 27 cubic feet.

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General reference

Trust, Methodology & Sources

Written by Calculover Editorial Team · Updated 2026-07-31

Editorial accountability

Author: Calculover Editorial Team - Editor

Owner: Calculover Editorial Team - Editorial owner

Last reviewed: 2026-07-31

Last verified: 2026-07-31

Methodology

Limitations & guidance

Soil volume = bed length × width × depth, converted to cubic feet and cubic yards (÷27). Bags needed = cubic feet ÷ the bag's stated coverage in cubic feet.

This is a geometric volume calculation, not a soil-science recommendation. It does not account for settling, irregular bed shapes, or specific soil-mix ratios — see the info box above for a settling allowance.

Professional guidance:

Primary sources

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Glossary

Key Terms Explained

6 terms

Raised bed A garden bed built above the surrounding grade, usually framed with wood, stone, or metal, and filled with a soil mix rather than relying on the native ground soil.

Soil volume The amount of space the soil fills inside the bed, calculated as length times width times depth. It's the number you use to order bulk soil or count bags.

Cubic yard A bulk volume unit equal to 27 cubic feet (a 3 ft by 3 ft by 3 ft cube). Garden centers and landscaping suppliers typically price and deliver soil, mulch, and compost by the cubic yard.

Cubic feet A volume unit equal to a 1 ft by 1 ft by 1 ft cube. Bagged soil products list their coverage in cubic feet, making it the easiest unit for comparing to bag sizes.

Garden bed depth How deep the soil layer is inside the bed, measured from the top of the fill to the base. Most vegetable beds use 8-12 inches of depth for healthy root growth.

Soil bags Pre-packaged bags of topsoil, garden soil, or compost, most commonly sold in 1 to 2 cubic foot sizes. The exact coverage is printed on the bag's label.

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Scenarios

Real-World Examples

3 worked examples

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Weekend gardener

Standard 4x8 bed

Length 8 ft Width 4 ft Depth 1 ft

An 8 ft by 4 ft bed filled 1 ft deep needs 32 cubic feet of soil — about 1.19 cubic yards. That's a typical single bulk-delivery order for a standard vegetable bed.

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Buying bagged soil

Bags needed for a small bed

Volume 32 ft³ Bag size 1.5 ft³

At 32 cubic feet needed and 1.5 cubic feet per bag, you'd need about 22 bags — rounding up ensures you don't run short partway through filling the bed.

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Multiple beds

Two beds, same size

Beds 2 x (8×4×1 ft) Total volume 64 ft³

Two identical 8 ft by 4 ft by 1 ft beds each need 32 cubic feet, so the combined order is 64 cubic feet — about 2.37 cubic yards — enough to justify a single bulk delivery.

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Deep Dive

Understanding the Raised Bed Soil Calculator

3 chapters · 3 min read

Filling a raised garden bed takes more soil than most gardeners expect, and buying too little or too much wastes money and trips to the garden center. This calculator turns your bed's measurements into a cubic-foot and cubic-yard total you can hand straight to a supplier.

How the Raised Bed Soil Calculator works

The calculator multiplies the bed's length, width, and depth to get cubic feet, then divides by 27 to convert to cubic yards, the unit most bulk soil suppliers use for pricing and delivery. If you enter dimensions in inches, they're converted to feet first so the volume math stays consistent.

Inputs and what they mean

Length and width are the inside dimensions of the bed frame. Depth is how deep you plan to fill it with soil — often less than the full wall height, since you may leave a couple inches of headroom. The optional bag size lets you convert the cubic-foot total into a bag count for bagged soil purchases.

Limits and edge cases

This calculator assumes a simple rectangular bed. For an L-shaped, circular, or tiered bed, split it into rectangular sections and sum the volumes, or use a dedicated volume calculator for that shape. It also doesn't account for settling — buy roughly 10-20% extra soil to cover compaction after watering.

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Questions

Frequently Asked Questions

6 questions

What formula does the Raised Bed Soil Calculator use?+

Volume equals length times width times depth (L × W × D). The calculator converts the result to cubic feet, then divides by 27 to show cubic yards, since one cubic yard equals 27 cubic feet.

How big is a cubic yard of soil?+

A cubic yard is a 3 ft by 3 ft by 3 ft cube, or 27 cubic feet. It's the standard bulk unit garden centers and landscaping suppliers use for pricing and delivery of soil, mulch, and compost.

What size are bagged soil products?+

Bagged topsoil, garden soil, and compost most commonly come in 1 to 2 cubic foot bags. Check the bag's label for the exact coverage, since sizes vary by brand and product line.

Should I buy extra soil for settling?+

Yes — add roughly 10-20% extra to the calculated volume. Loose soil settles and compacts after watering and over the first growing season, so a bed filled to the exact calculated volume ends up looking underfilled.

What soil mix should I use to fill a raised bed?+

A common mix is roughly 50-60% quality topsoil, 30-40% compost, and a smaller share of aeration amendments like perlite or coarse sand, though exact ratios vary by what you're growing and your local soil supplier's offerings.

How do I calculate soil for multiple raised beds?+

Calculate the volume for each bed separately using its own length, width, and depth, then add the cubic-foot totals together — or run this calculator once per bed and sum the results before ordering.

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Bed Dimensions

Soil Volume

Converting to Cubic Yards

Cubic Yards Needed

Buying Bagged Soil

Bags Needed

How to Use This Calculator

Measure the bed

Enter the dimensions

Read the soil volume

Check bags needed

Formula & Methodology

Trust, Methodology & Sources

Key Terms Explained

Real-World Examples

Weekend gardener

Buying bagged soil

Multiple beds

Understanding the Raised Bed Soil Calculator

How the Raised Bed Soil Calculator works

Inputs and what they mean

Limits and edge cases

Frequently Asked Questions

Get a branded PDF of your results

Raised Bed Soil Calculator

Bed Dimensions

Soil Volume

Converting to Cubic Yards

Cubic Yards Needed

Buying Bagged Soil

Bags Needed

How to Use This Calculator

Measure the bed

Enter the dimensions

Read the soil volume

Check bags needed

Formula & Methodology

Trust, Methodology & Sources

Key Terms Explained

Real-World Examples

Understanding the Raised Bed Soil Calculator

How the Raised Bed Soil Calculator works

Inputs and what they mean

Limits and edge cases

Frequently Asked Questions

Get a branded PDF of your results

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