Mulch Calculator — Cubic Yards & Bags for Your Beds

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.

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Mulch Calculator

Yards, bags & cost compare

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Tip: 1 cubic yard = 27 cubic feet and covers about 108 sq ft at a 3″ depth.

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Enter your bed sizes to see how much mulch to buy

How to Use the Mulch Calculator

  1. Measure each bed in feet — add up to three rectangles, or enter the total square footage if you already know it.
  2. Choose a depth — 3 inches is the sweet spot for weed control; 2″ for refreshing existing mulch, 4″ max around trees.
  3. Compare bulk vs bagged — enter a per-yard and per-bag price and the calculator tells you which is cheaper for your job.

🌷 Multi-bed friendly

Add up to three beds at once — the calculator totals the area so you make one trip to the garden center, not three.

🛍️ Bags & yards

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.

💲 Bulk vs bag math

Bagged mulch often costs 2–3× more per cubic foot than bulk — the comparison shows your actual savings.

How Much Mulch Do I Need?

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 / unitVolumeCoverage at 3″Typical 2026 price
Bagged mulch (small)2 cu ft8 sq ft$3–$6 per bag
Bagged mulch (large)3 cu ft12 sq ft$5–$9 per bag
Bulk delivery1 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 Calculator FAQ

At the recommended 3-inch depth, 100 square feet needs about 0.93 cubic yards of mulch — that is 25 cubic feet, or 13 two-cubic-foot bags (9 of the 3 cu ft bags). At 2 inches you need 0.62 yards, about 9 two-cubic-foot bags.
One cubic yard equals 27 cubic feet, so it takes 13.5 of the common 2 cu ft bags or 9 of the larger 3 cu ft bags to equal one yard of bulk mulch.
Spread mulch 2 to 4 inches deep — 3 inches is the sweet spot for most beds. Less than 2 inches lets sunlight through and weeds sprout; more than 4 inches can suffocate plant roots and trap excess moisture. Keep it a few inches away from tree trunks and stems.
Bulk mulch typically costs $30 to $60 per cubic yard in the US, plus a $25 to $75 delivery fee that many suppliers waive on larger orders. Premium dyed or hardwood mulch runs higher; economy ground cover runs lower.
Bulk is usually much cheaper per cubic foot: at $4 per 2 cu ft bag, a yard costs about $54 in bags versus $30 to $45 in bulk. Bags win for small jobs under a yard or during spring multi-bag sales, and they are easier to haul and store.
A 2 cu ft bag covers 12 square feet at 2 inches deep, 8 square feet at 3 inches, and 6 square feet at 4 inches. A 3 cu ft bag covers 18, 12 and 9 square feet at those same depths.
Mid-to-late spring, after the soil has warmed, is ideal — mulching too early keeps soil cold and slows growth. A second light top-up in fall helps insulate roots over winter. Established beds usually only need a 1 to 2 inch refresh each year.

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✔ Reviewed by the True Value Calc editorial team🗓 Last updated June 2026📚 Sources: Peer-reviewed formulas & official U.S. government data