Mulch Calculator
To mulch a 10 × 20 ft garden bed at the standard 3-inch depth you need about 1.85 cubic yards of mulch plus 10% waste — roughly 28 bags of 2 cu ft mulch.
Reviewed by The ponderloop teamUpdated 2026-07-15How we calculate
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0 cu yd + 0% waste = 0 cu yd
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How this number is calculated
0 cu yd (no waste added) ÷ 0.0741 cu yd per bag = 0 bags
Shopping list
- Bark mulch (2 cu ft bag)
- Garden wheelbarrow
- Bow rake
- Landscape fabric (weed barrier)
- Garden bed edging
- Garden gloves
0.0 cu yd — ~0% of a standard truck load
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Methodology & assumptions
Volume is calculated as bed length × width × (depth in inches ÷ 12), then divided by 27 to convert cubic feet to cubic yards. A waste percentage is added for settling and uneven bed edges, and the result is divided by the coverage per bag (about 0.0741 cu yd for a standard 2 cu ft bag) and rounded up to the next whole bag. Bulk delivery typically becomes more economical than bags once a bed needs more than roughly 2-3 cubic yards.
- Penn State Extension — mulching guidelines (2-3 in. depth for weed suppression)
- University of Maryland Extension — mulch depth and reapplication guidance
- Manufacturer bag-yield specs (2 cu ft bag = 0.074 cu yd)
- Typical US retail price range for bagged and bulk mulch, 2026
Worked examples
| Room | Result |
|---|---|
| 10 × 20 ft garden bed, 3 in depth, standard waste | 1.85 cu yd + 10% waste ≈ 2.04 cu yd → 28 bags |
| 15 × 8 ft new bed, 2 in depth, minimal waste | 0.74 cu yd + 5% waste ≈ 0.78 cu yd → 11 bags |
| 6 × 6 ft weed-prone bed, 4 in depth, standard waste | 0.44 cu yd + 10% waste ≈ 0.49 cu yd → 7 bags |
Frequently asked questions
- How much mulch do I need for my garden bed?
- Multiply the bed length by width in feet, multiply by the depth in feet (inches divided by 12), then divide by 27 to convert cubic feet to cubic yards. Add 10% for waste and settling, then divide by the coverage per bag (about 0.0741 cu yd for a 2 cu ft bag) and round up.
- How many bags of mulch are in a cubic yard?
- A cubic yard is 27 cubic feet, and a standard bag of bark or wood mulch holds 2 cubic feet, so it takes 13.5 bags (27 ÷ 2) to equal one cubic yard.
- How deep should I lay mulch — 2, 3, or 4 inches?
- 2 inches works for a light refresh on a bed that already has a mulch base, or for areas with well-controlled weeds. 3 inches is the standard recommendation for weed suppression and moisture retention in most garden beds — this calculator defaults to 3 inches. 4 inches is worth the extra material in weed-prone areas or around new plantings, but avoid piling mulch deeper than 4 inches or against trunks and stems ("volcano mulching"), which traps moisture and invites rot and pests.
- Is it cheaper to buy bagged mulch or have it delivered in bulk?
- For small beds under roughly 2-3 cubic yards, bagged mulch is usually more convenient and often close in price. Above that, bulk delivery is typically cheaper per cubic yard and saves a lot of trips, even though most suppliers have a minimum delivery of 1-3 cubic yards. Compare your bagged total from this calculator against a local supplier's per-yard price plus delivery fee before committing.
- How often should I re-mulch a garden bed?
- Organic bark or wood mulch breaks down and settles over time, so most beds need a fresh 1-2 inch top-up once a year, with a fuller reapplication to the full 3-inch depth every 2-3 years. Beds that dip below about 1 inch of remaining mulch lose their weed-suppression and moisture benefits and should be topped up sooner.