Add up to three flower beds (or enter total square feet), pick a depth, and see exactly how many cubic yards or bags of mulch to buy — plus whether bulk or bagged is cheaper.
Yards, bags & cost compare
Tip: 1 cubic yard = 27 cubic feet and covers about 108 sq ft at a 3″ depth.
Add up to three beds at once — the calculator totals the area so you make one trip to the garden center, not three.
Get the count in both 2 cu ft and 3 cu ft bags plus cubic yards, so any store’s packaging or a bulk delivery quote works.
Bagged mulch often costs 2–3× more per cubic foot than bulk — the comparison shows your actual savings.
The rule of thumb: 1 cubic yard of mulch covers 108 square feet at 3 inches deep (27 cu ft × 12 ÷ 3). The formula this calculator uses is square feet × depth in inches ÷ 324 = cubic yards. So a typical 10 × 4 ft flower bed at 3″ needs 40 × 3 ÷ 324 = 0.37 yd³ — exactly five 2 cu ft bags.
Depth matters for weed control. University extension services consistently recommend 2–4 inches: less than 2″ lets sunlight through and weeds germinate; more than 4″ can suffocate roots and hold too much moisture against stems. Keep mulch a couple of inches away from tree trunks and wooden siding — the “mulch volcano” piled against a trunk invites rot and pests. A 2″ top-up each spring is usually enough once a bed is established.
| Bag / unit | Volume | Coverage at 3″ | Typical 2026 price |
|---|---|---|---|
| Bagged mulch (small) | 2 cu ft | 8 sq ft | $3–$6 per bag |
| Bagged mulch (large) | 3 cu ft | 12 sq ft | $5–$9 per bag |
| Bulk delivery | 1 cu yd (27 cu ft) | 108 sq ft | $30–$60 per yard + delivery |
Run the price math before you buy: at $4 per 2 cu ft bag, a cubic yard costs 13.5 bags × $4 = $54 bagged versus $30–$45 in bulk. For one small bed, bags win on convenience; for 2+ yards, bulk delivery usually saves real money even after a $25–$75 delivery fee — and many US suppliers waive it above 3–5 yards. Spring sales (often 4–5 bags for $10) can flip the math back to bags, which is why the calculator compares both with your actual local prices.
Mulch is sold by the cubic yard in bulk and by the bag in retail, and the two are easy to confuse: a standard bag is 2 cubic feet, so it takes 13.5 bags to make one cubic yard. Depth is the variable that matters most and is most often overdone. Two to three inches suppresses weeds and retains moisture; deeper than four inches starts to starve roots of oxygen, and piling mulch against a trunk — the "mulch volcano" — traps moisture against the bark and invites rot. Organic mulch also decomposes, so a bed typically needs topping up by an inch each year rather than a full replacement.
Cubic feet = Area (sq ft) × (depth in inches ÷ 12)Cubic yards = cubic feet ÷ 27Bags (2 cu ft each) = cubic feet ÷ 21 cubic yard = 13.5 standard bagswhere:
Assumptions: Organic mulch settles and decomposes, losing roughly an inch a year. Keep it several inches clear of trunks and stems regardless of bed depth.
Convert bed area into both bulk and bagged quantities, and compare the cost.
Result4.17 cubic yards — or 57 bags, at nearly $100 more
Bulk delivery is 38% cheaper here and the gap widens with volume, which is why bulk is worth it above about two cubic yards if you can accept a pile on the driveway. Dropping to a 2-inch depth would need only 2.78 cu yd — and is better for the plants.