Mulch Calculator
Enter your bed dimensions or total area to find out how much mulch you need — in cubic yards and bag counts.
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Not sure how large your area is? Use our land area calculator to measure any yard or garden bed on a map.
Your Results
Volume needed
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2 cu ft bags
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3 cu ft bags
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Related calculator:
Raised Bed Soil Calculator →Filling raised beds too? Calculate how much soil you need alongside your mulch order.
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How We Calculate
Formula, assumptions, and sources
Inputs you provide
- Area — either length × width or a total square footage you already know
- Depth — how thick a layer of mulch to spread (default 3 inches / 7.5 cm)
Formula
Volume = area × depth, converted to the volume unit mulch is sold in.
- Imperial:
cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27 - Metric:
cubic meters = area (sq m) × depth (cm) ÷ 100
Bag count = total cubic feet ÷ bag size, rounded up. The calculator shows both 2 cu ft and 3 cu ft bag counts because both sizes are common at US retailers.
Assumptions
- Default depth is 3 inches (7.5 cm). Most garden beds use 2–4 inches; tree rings use 2–3 inches and should never be piled against the trunk.
- Bag counts use 2 cu ft and 3 cu ft — the standard sizes at Home Depot, Lowe's, and most garden centers. If your supplier uses a different bag size, take the total cubic feet and divide by their bag size.
- Volume is calculated for loose, uncompressed mulch. Compressed bales and bagged mulch expand when opened; the calculator reflects the expanded volume.
Sources
- Mulch depth recommendations (2–4 inches for most beds) are consistent across US university extension services — see our mulch depth guide for the specifics.
Limitations
- Different mulch types have different bulk densities. This calculator treats volume as volume — a cubic yard of pine bark and a cubic yard of wood chips cover the same area at the same depth, but they weigh and behave differently in the bed.
- Coverage is theoretical. Real beds have uneven surfaces, edges, and obstacles, so buying an extra 5–10% is a reasonable buffer for larger jobs.
- For driveways, pathways, or drainage projects, use the gravel calculator instead — mulch is not a load-bearing material.
Frequently Asked Questions
How many bags of mulch are in a cubic yard?
One cubic yard equals 27 cubic feet. You'll need 14 bags of 2 cu ft mulch or 9 bags of 3 cu ft mulch per cubic yard.
How much area does 1 yard of mulch cover?
At 3 inches deep (the standard), 1 cubic yard covers about 108 square feet. At 2 inches, it covers about 162 sq ft.
How much mulch do I need?
Measure your bed length × width to get square footage, then use our calculator above with a 3-inch depth for most garden beds.
How deep should mulch be?
Most garden beds benefit from 2–4 inches of mulch. Three inches is the standard recommendation — enough to suppress weeds and retain moisture without suffocating roots.