Mulch Calculator
Add your garden beds, choose the mulch depth and see how much mulch you need in cubic yards, cubic feet or cubic meters, plus how many bags to buy and what it will cost.
| Bag size | Bags |
|---|
How to use the Mulch Calculator
- Choose units: feet and inches, or meters and centimeters.
- Add each bed, pick its shape and enter its size. Use Total area if you already know the square footage.
- Set the depth. 2 to 3 inches (5–8 cm) is typical for refreshing beds, 3 to 4 inches (8–10 cm) for new beds.
- Press Calculate to see the volume and the number of bags in each common size.
- Add a bag or bulk price to compare the cost of bagged and bulk mulch.
Mulch formula
- Cubic feet = area (sq ft) × depth (in) ÷ 12
- Cubic yards = cubic feet ÷ 27
- Cubic meters = area (m²) × depth (cm) ÷ 100
- Bags = volume ÷ bag size, rounded up to a whole bag
Example: a 10 × 10 ft bed is 100 sq ft. At 3 inches deep: 100 × 3 ÷ 12 = 25 cubic feet, and 25 ÷ 27 = 0.93 cubic yards (0.71 m³). That is 13 bags of 2 cu ft (25 ÷ 2 = 12.5, rounded up) or 9 bags of 3 cu ft.
Area formulas for each bed shape: rectangle = length × width; circle = π × diameter² ÷ 4; triangle = base × height ÷ 2.
How far a cubic yard of mulch goes
| Depth | Coverage per cubic yard | Coverage per 2 cu ft bag | Coverage per m³ |
|---|---|---|---|
| 1 in (2.5 cm) | 324 sq ft | 24 sq ft | 40 m² |
| 2 in (5 cm) | 162 sq ft | 12 sq ft | 20 m² |
| 3 in (7.5 cm) | 108 sq ft | 8 sq ft | 13.3 m² |
| 4 in (10 cm) | 81 sq ft | 6 sq ft | 10 m² |
Mulching tips
- Depth: 2–3 in (5–8 cm) to top up existing mulch, 3–4 in (8–10 cm) for new beds or weed-prone areas. Fine mulches settle more, so use the upper end.
- Keep it off stems: leave a gap of a few inches around tree trunks and plant crowns. Piled-up "mulch volcanoes" trap moisture and invite rot and pests.
- Weed first: pull weeds and water the soil before mulching. A layer of cardboard under the mulch helps smother persistent weeds.
- Bag sizes: US bags are usually 2 or 3 cu ft; 1.5 cu ft bags are common for decorative mulch. European and UK bags are sold in liters (40, 50, 60 or 75 L). One cubic foot is 28.3 liters.
- Buy a little extra: mulch compacts after spreading and watering. Rounding up to the next whole bag or adding about 5–10% covers settling and uneven ground.
Frequently asked questions
How much mulch do I need for 100 square feet?
At 3 inches deep, 100 sq ft needs 100 × 3 ÷ 12 = 25 cubic feet, which is 25 ÷ 27 = 0.93 cubic yards. That is 13 bags of 2 cu ft or 9 bags of 3 cu ft.
How do you calculate cubic yards of mulch?
Multiply the area in square feet by the depth in inches and divide by 12 to get cubic feet. Then divide by 27, because one cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet.
How many square feet does a yard of mulch cover?
One cubic yard covers about 324 sq ft at 1 inch, 162 sq ft at 2 inches, 108 sq ft at 3 inches and 81 sq ft at 4 inches deep.
How deep should mulch be?
Most beds need 2 to 4 inches (5 to 10 cm). Less than 2 inches does little to stop weeds, and more than 4 inches can keep water and air from reaching roots. Keep mulch a few inches away from tree trunks and plant stems.
How many bags of mulch are in a yard?
One cubic yard is 27 cubic feet, so it equals 13.5 bags of 2 cu ft or 9 bags of 3 cu ft. In metric, one cubic meter fills 25 bags of 40 L or 20 bags of 50 L.
Is bulk mulch cheaper than bags?
Usually, for larger jobs. Bulk mulch is sold by the cubic yard or cubic meter and is often cheaper per unit volume, but may include a delivery fee. Bags are easier for small beds and spot touch-ups.