Mulch Calculator
Figure out exactly how much mulch to buy for your beds, borders, and garden paths — so you’re not making a second trip to the store, or stuck with three leftover bags in the garage.
Recommended depth for bark/wood chips: 2–4 inches.
How much mulch depth do you actually need?
Too thin, and mulch won’t suppress weeds or hold in moisture. Too thick, and it can actually block water and air from reaching plant roots. Here’s a general guide by mulch type:
| Mulch type | Recommended depth |
|---|---|
| Bark / wood chips | 2–4 inches |
| Shredded hardwood | 2–4 inches |
| Pine straw | 3–4 inches |
| Straw | 2–3 inches |
| Shredded leaves | 3–4 inches |
| Compost | 1–3 inches |
| Rubber mulch | 2–3 inches |
| Gravel / stone | 2–4 inches |
A few tips before you buy
- Keep mulch away from stems and trunks. Piling mulch directly against a plant stem or tree trunk traps moisture against it and can encourage rot — leave a small gap.
- Buy slightly more than the exact number. Settling, uneven ground, and edging losses typically eat up 5–10% more than the raw calculation — our result already reflects the volume, but rounding up your bag order is still wise.
- Organic mulches need topping up. Bark, straw, and leaf mulches break down over a season or two and will need a refresh — rubber and gravel mulches last much longer but don’t feed the soil.
Frequently asked questions
One cubic yard equals 27 cubic feet, so it takes about 13–14 bags of the common 2 cubic foot size to cover 1 cubic yard. The cost calculator above works this out automatically for whichever bag size you choose.
Bulk (by the cubic yard) is almost always cheaper per unit once you need more than around 2–3 cubic yards, but it requires delivery or a truck to haul it. For small beds, bagged mulch is usually more practical despite the higher per-unit cost.
Organic mulches (bark, straw, leaves) typically need topping up once a year, or every other year for slower-decomposing types like large bark nuggets. Rubber and gravel mulches can last many years with little to no replenishing.