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Calculation details
Planning estimate only. Verify dimensions, waste, coverage, product specifications, and local requirements before purchasing materials.
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What does this calculator estimate?
Mulch and soil calculator: convert bed dimensions into cubic yards of mulch, soil, or compost for accurate landscape material orders. Free, no signup.
How this calculator works
Formula
Cubic yards = length (ft) x width (ft) x depth (in) / 12 / 27, multiplied by (1 + waste).
Worked example
200 sq ft at 3 inches deep with 5% waste: 1.85 cubic yards base, 1.94 with waste, about 27 two-cubic-foot bags or 18 three-cubic-foot bags.
Frequently asked questions
How does the mulch calculator determine the amount of mulch I need?
Our mulch calculator uses your inputted area dimensions and desired depth to calculate the exact volume of mulch required in cubic yards or feet.
Do I need to create an account or sign up to use the mulch calculator?
No, this is a no-signup, browser-based tool, so you can calculate your soil and mulch needs instantly without creating an account or sharing personal data.
Is my input data safe when using the mulch calculator?
Yes, because it is a no-signup, browser-based tool, all calculations are processed locally on your device and no personal data or inputs are ever stored or transmitted.
Cite this tool
BoringToolsKit. “Mulch and Soil Calculator.” boringtoolskit.com/mulch-soil-calculator/. Free to reference in articles, syllabi, and answer posts with a link.
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Worked example: 20 x 10 ft at 3 inches with 10% waste
A 20 x 10 ft bed, 3 inches deep, 10% waste. Area: 20 x 10 = 200 sq ft. Depth in feet: 200 x 3 / 12 = 50 cu ft. Yards: 50 / 27 = 1.8519, shown as 1.85. With waste: 1.8519 x 1.10 = 2.037, shown as 2.04 cu yd.
Bags divide that same 2.037 cu yd: 1.5 cu ft needs 2.037 x 18 = 36.67, up to 37; 2 cu ft needs 2.037 x 13.5 = 27.50, up to 28; 3 cu ft needs 2.037 x 9 = 18.33, up to 19. Rounding happens after the multiplication, not before.
The coverage table runs the volume backward: one cubic yard at 1 inch deep covers 27 x 12 = 324 sq ft, so this order covers 660, 330, 220, and 165 sq ft at 1 to 4 inches. At 3 inches, 220 is the 200 sq ft bed plus the allowance.
Where the numbers bend: zero waste, deep typos, and loose depth
At 0% waste, a 10 x 10 bed at 3 inches needs 100 x 3 / 12 = 25 cu ft = 0.93 cu yd, or 13 bags of 2 cu ft (12.5 material bags), 17 of 1.5 cu ft, and 9 of 3 cu ft. It covers no spillage or uneven ground.
Zero or negative length, width, or depth, or negative waste, returns the invalid message. Waste has no upper bound: a typo of 100 instead of 10 doubles the 200 sq ft order from 2.04 to 3.70 cu yd. Fractional depths work: 0.5 in over 200 sq ft is 0.31 cu yd, still 5 bags because 4 hold only 8 cu ft.
It assumes a true rectangle at uniform depth: a curved edge or 3 ft path inside it still counts as mulch. Depth is read loose, so a 3 in layer settles lower; the waste field is the only lever for that.