Landscaping
Enter your bed size and mulch depth to get the volume — cubic feet, bulk cubic yards, how many bags to buy, and how much area each bag covers.
Mulch needed
—Enter bed size and depth to estimate mulch.
| Total volume | — |
|---|---|
| Bulk (cubic yards) | — |
| Bags to buy | — |
| Coverage per bag | — |
| Estimated cost | — |
Mulch volume is area × depth. We convert to cubic feet, divide by 27 for cubic yards, and by the bag size (usually 2 cu ft) for the bag count. We also show how many square feet one bag covers at your chosen depth, so you can sanity-check the total.
For a bag or two, bagged mulch is easy. Past roughly 8–10 bags, bulk mulch by the cubic yard is usually cheaper and faster — the calculator shows both the bag count and the cubic-yard figure so you can compare before you load the car.
Standard volume math; 1 cubic yard = 27 cubic feet. Estimates only.
More than 3–4 inches can suffocate roots, hold moisture against stems, and grow mould. Keep beds around 2–3 inches, and never heap mulch against trunks or stems — the "mulch volcano" rots the bark it touches.
Old mulch that has crusted or matted sheds water instead of soaking it up. Rake it loose first, then top up — otherwise your fresh layer just sits on a barrier and the plants below stay dry.
Bags are convenient for a spot or two, but past roughly 8–10 bags, bulk mulch by the cubic yard is cheaper and saves a lot of loading and hauling. The calculator shows the cubic-yard figure so you can compare.
Loose mulch compacts after the first rain, so a bed spread to exactly 3 inches ends up thinner. Spread a little over your target depth so it settles into the coverage you actually want.
Multiply the bed area by the depth. A 10 × 20 ft bed (200 sq ft) at 3 inches deep needs about 50 cubic feet — roughly 25 bags of 2 cu ft, or about 1.85 cubic yards in bulk. Use the calculator for your exact bed.
2–3 inches is standard for most beds; use 3–4 inches for weed suppression and moisture retention. Going deeper than 4 inches can suffocate roots, so top up to 3 inches rather than piling on.
A cubic yard is 27 cubic feet, so it equals about 13.5 bags of 2 cu ft (or 9 bags of 3 cu ft). Once you need more than about 8–10 bags, bulk mulch by the cubic yard is usually cheaper.
A 2 cu ft bag covers about 12 sq ft at 2 inches deep, or 8 sq ft at 3 inches deep. The calculator shows coverage per bag for the depth you choose.
Organic mulches (bark, wood chips) break down over a year, so most gardens just top up 1–2 inches each spring to keep about 3 inches — you rarely need to replace it all. Stone and rubber mulch don't decompose and don't need topping up.
Usually not — old mulch breaks down into the soil. Only pull some back if it's matted, mouldy, or already piled past about 4 inches; rake what's there to loosen it, then top up to your target depth.
About 3 inches blocks most weeds while still letting water and air through. Under 2 inches won't suppress them, and over 4 inches can starve roots of oxygen and hold too much moisture against stems.
Estimate only, based on standard volume math. Coverage varies with mulch type, shredding, and settling. Bag counts are rounded up. Confirm against your supplier's bag coverage before buying.