Garden Soil Calculator for Raised Beds and Gardens

Calculate cubic feet, cubic yards, and bag count of garden soil needed for raised beds, in-ground gardens, and containers. Built for U.S. gardeners and landscapers planning soil orders in 2026.

Updated June 2026 Volume Formulas Sourced Free, No Signup Required Sources Cited No Data Stored or Transmitted

Built by Muhammad Ramzan Babar, physics researcher (PhD candidate). Reviewed by site author.

Garden Soil Volume and Cost Estimator

Bed Shape

Bed Dimensions

Length (ft)

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Width (ft)

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Depth and Quantity

Soil Depth (inches)

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10-12 in for vegetables, 6-8 in for herbs, 12-18 in for root crops.

Number of Beds

Settling Allowance

Extra for Settling

Volume Formula Explained

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Length x Width x Depth

For rectangular beds, cubic feet equals length (ft) times width (ft) times depth (in) divided by 12.

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Pi x Radius Squared x Depth

For circular beds, cubic feet equals pi times radius squared (ft) times depth (in) divided by 12.

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Settling and Bags

Add a settling percentage, then divide total cubic feet by bag size to get the number of bags to buy.

Soil Depth Guide by Plant Type

Plant Type	Recommended Depth	Notes
Herbs	6 to 8 inches	Shallow-rooted, tolerates less depth
Leafy Greens and Vegetables	10 to 12 inches	Standard depth for most vegetable beds
Root Crops (Carrots, Potatoes)	12 to 18 inches	Deeper soil needed for tuber and root expansion
Perennial Beds and Shrubs	18 to 24 inches	Deeper mix supports established root systems

Garden Soil, Topsoil, and Potting Soil Compared

Garden soil is topsoil blended with compost and organic matter, formulated for in-ground beds and raised planters. It differs from plain topsoil, which is unamended native soil often used for grading and filling low spots rather than planting directly.

Potting soil is a separate product entirely, a soil-free mix of peat, bark, and perlite designed for container drainage rather than garden beds. Mixing garden soil with additional compost improves nutrient content for vegetable beds specifically.

One cubic yard equals 27 cubic feet, the standard conversion used across bulk soil, mulch, and compost calculations. Bulk delivery pricing is quoted per cubic yard, while bagged soil at home improvement stores is priced and sized per cubic foot.

Step-by-Step Example: First-Time Raised Bed

Step 1: Measure the Bed

Bed size: 4 ft x 8 ft rectangular frame

Target depth: 12 inches for vegetables

Volume: 4 x 8 x (12 / 12) = 32 cubic feet.

Step 2: Add Settling and Convert

Settling factor: 10% for compaction after watering

Cubic yards: 32 / 27 = 1.19 cu yd before settling

With settling: 32 x 1.10 = 35.2 cubic feet, or about 1.30 cubic yards.

Step 3: Convert to Bags

Bag size: 1.5 cu ft bags

Bags needed: 35.2 / 1.5 = 23.5, rounded up to 24 bags

At $6.98 per bag, total cost: 24 x $6.98 = $167.52 for one 4x8 bed at 12 inches deep.

Common Soil Calculation Errors

Forgetting to convert depth from inches to feet before multiplying, which inflates the result by a factor of 12.
Skipping the settling allowance, leading to a bed that appears underfilled a few weeks after installation once the soil compacts.
Using outside frame dimensions instead of inside planting dimensions, which overstates the volume needed by the thickness of the bed walls.
Assuming garden soil, topsoil, and potting soil are interchangeable, when each has different composition and price per cubic foot.
Comparing bag price to bulk price without converting both to the same unit, since bags are priced per cubic foot and bulk is priced per cubic yard.

Bulk Versus Bagged Soil Costs

Bagged garden soil runs $4 to $8 per 1.5 cu ft bag at most U.S. retailers in 2026, which works out to roughly $2.67 to $5.33 per cubic foot. Bulk garden soil blends delivered by the yard typically cost $25 to $60 per cubic yard, or about $0.93 to $2.22 per cubic foot.

The bulk option becomes more cost-effective once a project exceeds 1 to 2 cubic yards (27 to 54 cubic feet), since bagged products carry retail packaging markup. Many bulk suppliers also charge a delivery fee that should be added separately when comparing total project cost.

For larger builds spanning multiple beds, review the cubic yard calculator to confirm total volume before requesting a bulk delivery quote, and check the landscaping cost calculator for full project budgeting including labor.

Frequently Asked Questions

How much soil do I need for a 4x8 raised bed? +

A 4 ft by 8 ft raised bed at 12 inches deep needs 32 cubic feet of soil, which equals about 1.19 cubic yards. That works out to 32 bags of 1 cu ft soil, 16 bags of 2 cu ft soil, or roughly 21 bags of 1.5 cu ft soil.

How deep should soil be in a raised garden bed? +

Most vegetables need 10 to 12 inches of soil depth for healthy root development. Herbs can grow well in 6 to 8 inches, while root crops like carrots and potatoes benefit from 12 to 18 inches.

Should I add extra soil for settling? +

Yes. Add 10 percent extra soil volume to account for settling and compaction after the first few waterings, since loose soil compresses once it absorbs moisture and beds down.

How many cubic feet are in a cubic yard of soil? +

One cubic yard equals 27 cubic feet. Bulk soil delivery is typically priced and sold by the cubic yard, while bagged soil is sold by the cubic foot, so converting between the two is necessary to compare cost.

Is it cheaper to buy soil in bags or bulk? +

Bulk soil delivered by the cubic yard is almost always cheaper per cubic foot than bagged soil once a project exceeds roughly 1 to 2 cubic yards (27 to 54 cubic feet), since bulk pricing avoids retail packaging markup.

What is the difference between garden soil, topsoil, and potting soil? +

Garden soil is topsoil blended with compost and amendments for in-ground and raised bed planting. Topsoil alone is unamended native soil, and potting soil is a soil-free mix of peat, bark, and perlite made specifically for containers.

How much does garden soil cost per cubic yard in 2026? +

Bulk garden soil blends typically run $25 to $60 per cubic yard delivered, depending on region and mix quality, while bagged garden soil runs $4 to $8 per 1.5 cu ft bag at most retailers.

Sources and Methodology

Raised bed volume formula and worked example: Length (ft) x Width (ft) x Depth (in) / 12 = cubic feet. HowMuchStuff, Raised Bed Soil Calculator
Cubic yard conversion: 1 cubic yard = 27 cubic feet, standard across bulk material calculators. Alluvial Soil Lab, Soil Calculator
Soil depth recommendations by plant type (herbs, vegetables, root crops), consistent with multiple raised bed calculator guidance.
Settling allowance guidance: 10% standard addition for compaction after watering.
Bag and bulk pricing reference: bagged soil $4-$8 per 1.5 cu ft, bulk soil $25-$60 per cubic yard (2026 market data).

Disclaimer

This calculator provides estimates for planning purposes. For permitted structural work, foundations, multi-story construction, retaining walls over 4 feet, and commercial projects, calculations must be verified by a licensed structural engineer per IBC 2024 §1604. ConcreteCalculate.com is not liable for structural decisions made from these estimates.

Privacy Note

Calculations run in your browser and are sent only to our server for processing this request. No project data, inputs, or results are stored or transmitted to third parties.