A cubic yard of mulch holds 13.5 bags at 2 cu ft each, or 9 bags at 3 cu ft each. The math is 27 ft³ / bag_size_ft³— that's it. Most retailers round up to 14 of the 2 cu ft bags or 9 of the 3 cu ft bags. At 3″ depth, 1 cubic yard covers 108 sq ft; at 2″ it covers 162 sq ft. A cubic yard is 14× 2cu-ft bags or 9× 3cu-ft. The trap is that fluffy fresh mulch yields LESS coverage than a settled yard a month later — you need the cubic-yard math, not the bag-count math.
Run the actual order through the mulch yardage calculator — it surfaces the bag count for both common sizes plus the practical cubic-yard order with the settling cushion baked in.
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Hi, I'm the SiteworkMath assistant. I answer questions about the calculators and guides on this site — concrete yardage, topsoil, mulch, tile, and decking material math. I'm not a structural engineer or a licensed contractor; I'm a calculator built around the math that James Wu — Chicago-area flipper — uses on his own jobs. For structural decisions (joist sizing, beam spans, footing depth in your soil + climate, anything that needs a permit) talk to a licensed structural engineer or your local building department.
How pros actually do this
On a Chicago-suburbs flip in 2022 the listing went up the morning after the mulch went down — three cubic yards bagged across four landscape beds because the alley wouldn't take a delivery truck. That's 41 bags at 2 cu ft each, ceiling of 3.0 × 13.5. Stacked two-deep along the fence line, the pickup made two runs from Home Depot. By the open house six weeks later the surface had compacted to roughly 2.25″ on a 3″ spread. Same yardage, less visible depth — the coverage number that matters six weeks later isn't the same coverage number on the bag.
Coverage at depth is where the bag-count math starts hiding things. At 3″ a cubic yard covers 108 sq ft on day one. After Penn State Extension's 25% bulk-volume settling loss, the same yard is covering closer to 81 sq ft worth of visibledepth — the surface area is the same, but the layer is now ~2.25″. If a contractor quoted you a yard for 108 sq ft and you check it in August, you can't tell whether they shorted you or it just settled. The cubic-yard order is the only audit-proof number.
One operator opinion: above 1 cubic yard, switch to bulk if access allows. Bagged mulch above 30-40 bags is a back injury waiting for a wheelbarrow, and the per-yard price advantage on bulk grows fast — often 30-40% cheaper at the supplier's 3 yd³ minimum. Below 1 yd³ stay bagged; the delivery fee plus minimum-order penalty erases the per-yard savings.
The bag-count math, line by line
1. A cubic yard is 27 cubic feet. Always.
Three feet × three feet × three feet. This is the only number in mulch math that doesn't depend on the supplier or the bag or the mulch-type. 1 yd³ = 27 ft³.
2. Divide by bag size in cubic feet to get bags per yard.
For 2 cu ft bags: 27 / 2 = 13.5 bags. For 3 cu ft bags: 27 / 9 = 9 bags. The 13.5 is the trap — you can't buy half a bag, so the practical answer is 14. The 9 lands clean.
3. Multiply by your cubic-yard order to get total bags.
For an order of N cubic yards: ceil(N × 13.5) at 2 cu ft, or ceil(N × 9) at 3 cu ft. The ceiling matters at every step — most fractional bag counts round up to the next whole bag.
4. Cross-check against coverage at depth.
Coverage in sq ft = 27 / (depth_in / 12). At 3″ that's 108 sq ft per yard; at 2″ it's 162. Apply 25% settling loss for first-year applications (Penn State Extension) to get the post-summer effective coverage. If the calc says you need 4 yd³ but the bed is 400 sq ft at 3″, that's about right — 400 / 108 = 3.7 yd³ exact, rounding to 4.0 with cushion.
Coverage tables
The two numbers most operators want side by side: how much area a cubic yard covers at standard depths, and how many bags that converts to. Both tables are the engine in lib/sitework/mulch.ts rendered as a lookup.
Coverage at depth, per cubic yard:
| Depth | Sq ft per cubic yard | Settled coverage (after 6 weeks, 25% loss) |
|---|---|---|
| 1″ | 324 | 243 |
| 2″ | 162 | 122 |
| 3″ | 108 | 81 |
| 4″ | 81 | 61 |
Bag count, per total cubic yards:
| Cubic yards | 2 cu ft bags | 3 cu ft bags |
|---|---|---|
| 0.5 | 7 | 5 |
| 1.0 | 14 | 9 |
| 2.0 | 27 | 18 |
| 3.0 | 41 | 27 |
| 5.0 | 68 | 45 |
All counts are ceilings of yd³ × 13.5 (2 cu ft) or yd³ × 9 (3 cu ft).
Run the math yourself
Type your bed area below. The calculator's “Ornamental” preset uses 3″ by default and surfaces the bag count for both 2 cu ft and 3 cu ft sizes alongside the cubic-yard order.
Where this number breaks down
A few traps that put the math on the wrong side of the order:
- Bag labels lie about coverage.“Covers 12 sq ft” on a 2 cu ft bag assumes 2″ depth and post-settling volume. At 3″ depth (the Penn State Extension mid-range for landscape beds) the same bag covers 8 sq ft. Trust the cubic-yard math, not the bag printing.
- Settling kills first-year coverage by ~25%. Penn State Extension on landscape-tree mulching: fresh wood-chip mulch loses 25-30% of its bulk volume in the first 6 weeks as it compresses. A 3″ application becomes 2-2.25″ by mid-summer. Year 1 calcs need to add the cushion back in; refresh applications on already-settled beds can skip it.
- Fine vs coarse mulch packs differently.Fine-shred and dyed mulch packs ~10% denser than coarse wood chips, so it covers about 10% more area per cubic yard at the same depth — but it also settles faster, so the post-6-week effective coverage is roughly net-equivalent. Don't bake the fine-coverage advantage into the order.
- Retailers round 13.5 up to 14, exact math doesn't. 13.5 isn't a buyable bag count. Some operators try to skip the half-bag and order 13 — that leaves you ~1 cu ft short, which exposes a 6-8 sq ft strip at 2″ depth. Always round up.
- Bulk vs bagged inverts at the supplier minimum. Above 3 yd³, bulk runs 30-40% cheaper per yard than bagged in the Chicago suburbs. Below 3 yd³, the supplier minimum forces a short-load fee that erases the savings — bagged wins on practical cost. The crossover sits exactly at the supplier minimum, not at the per-yard price comparison.
Frequently asked
How many bags of mulch are in a yard?
A cubic yard holds 13.5 bags at 2 cu ft each, or 9 bags at 3 cu ft each — the math is 27 ft³ divided by the bag size in ft³. Most retailers and landscape suppliers round up: 14 of the 2 cu ft bags or 9 of the 3 cu ft bags. The half-bag at 13.5 is the trap — buying 13 leaves you ~1 cu ft short, which is enough to expose dirt across a 6-8 sq ft strip at 2″ depth.
How much area does a cubic yard of mulch cover?
At 3″ depth, 1 cubic yard covers 108 sq ft. At 2″ it covers 162 sq ft, at 1″ it covers 324 sq ft, and at 4″ it covers 81 sq ft. Penn State Extension calls out the 2-4″ range for landscape beds. Those are spread-time numbers though — fresh wood-chip mulch loses ~25% of its bulk volume in the first 6 weeks, so plan on roughly 81 sq ft of effective coverage at 3″ once it settles.
How many cubic yards do I need for 500 sq ft at 3″?
500 sq ft × (3″ / 12) / 27 = 4.63 yd³ exact. With the standard 5% waste cushion plus the 25% first-year settling adjustment Penn State Extension flags, that rounds up to 6.0 yd³ practical. At 2 cu ft per bag that's 81 bags; at 3 cu ft it's 54. Above the 3 yd³ supplier minimum so bulk delivery is almost always cheaper than bagged, assuming the truck can reach the drop.
Why don't my coverage numbers match the bag label?
Bag labels typically read "covers 12 sq ft" or similar — that assumes 2″ depth applied to settled (already compressed) mulch. Two problems: most landscape beds want 3″ not 2″ (Penn State Extension mid-range), and fresh-out-of-the-bag mulch has more bulk volume than the same mulch six weeks later. The cubic-yard math (27 ft³ / depth in ft) gets you to the actual order; the bag label gets you to optimistic-marketing coverage.
Does the bag size affect total mulch needed?
Total volume is the same — 27 cubic feet either way. What changes is bag count and per-bag cost. 2 cu ft is the most common size at big-box (Home Depot, Lowe's, Menards) and runs $3-5 per bag in the Chicago suburbs. 3 cu ft is more common at landscape-specific suppliers and runs $5-7 per bag. The 3 cu ft bags are 13% cheaper per cubic foot on average, but they're heavier — 50-60 lb each vs 35-40 lb for 2 cu ft. For more than ~30 bags, the lifting math matters as much as the price math.
How much does a yard of mulch weigh?
Roughly 800-1,000 lb dry, depending on material — hardwood mulch sits at the high end, pine bark at the low end. Wet (after rain) it climbs to 1,200-1,500 lb. That's why the 3 yd³ supplier minimum exists: a residential 1/2-ton pickup can technically haul 1 yd³, but you're at the load limit. For 2+ yd³ you want a delivery truck or a trailer rated for the weight.
Related guides
- How much mulch do I need for my garden bed →
- Mulch: square yard vs cubic yard →
- How much mulch is in a cubic yard →
- Mulch calculator (cluster anchor) →
Once the bag count is set, the next decision is depth and area for the actual bed. How much mulch do I need for my garden bed covers it.
By James Wu. Bag-count and coverage math is site arithmetic, formulas shown above. Mulch depth recommendations + the 25% first-year settling factor from Penn State Extension — Mulching Landscape Trees (the 2-4″ depth range and the bulk-volume-loss observation that drives the settled-coverage column). Arboriculture standard via ANSI A300 (Tree Care Industry Association) for the formal 2-4″ depth specification. Tree-and-shrub mulch-depth cross-check from Iowa State Extension — Mulch Depth Around Trees and Shrubs. Engine logic in lib/sitework/mulch.ts. Not arboriculture advice — for tree-care decisions specific to your trees, work with an ISA-certified arborist. Full methodology.