Mulch Calculator
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Use this mulch calculator to estimate the amount of mulch you need for your garden, landscape beds or other project.
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Disclaimer: Whilst every effort has been made in building our calculator tools, we are not to be held liable for any damages or monetary losses arising out of or in connection with their use. Full disclaimer.
How much mulch do I need?
Mulch is commonly sold in cubic yards. A single cubic yard of mulch flooring is enough to cover an area of 324 square feet at 1 inch deep or 108 square feet at 3 inches deep (the most common mulching depth).
Coverage for 1 cubic yard at common depths:
| Depth | Coverage (sq ft) |
|---|
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
1 Cubic Yard of Mulch
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3ft × 3ft × 3ft
=27 cubic feet
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~13.5 bags
(2 cu ft bags)
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~400-800 lbs
depending on type
The most commonly recommended mulch depth is 2-4 inches. A 3-inch depth is often considered ideal — it's thick enough to suppress weeds and retain moisture while still allowing water and air to reach plant roots.
If you have an existing layer of mulch, you can simply top it up. Measure the current depth and subtract from your target depth to find out how much additional mulch you need.
How many bags of mulch in a cubic yard?
A cubic yard of mulch measures 3 feet × 3 feet × 3 feet, totaling 27 cubic feet.
In 2 cubic foot bags, that equals 13.5 bags. In 3 cubic foot bags, that equals 9 bags.
Most bagged mulch at home improvement stores comes in 2 cubic foot bags. Mulch can also be purchased in bulk by the cubic yard, which is typically more economical for larger projects.
Number of 2 cubic foot bags to make 1 cubic yard:
27 ÷ 2 = 13.5 bags (round up to 14)
Number of 3 cubic foot bags to make 1 cubic yard:
27 ÷ 3 = 9 bags
For most home gardening projects, bags offer the convenience of easier handling and transport. For large projects (over 3-4 cubic yards), consider ordering bulk mulch by the yard, which is usually delivered by truck.
Mulch coverage per bag and per yard
Coverage in Cubic Yards:
| Depth | 1 Cubic Yard covers | 2 Cubic Yards covers |
|---|
| 1 inch | 324 sq ft | 648 sq ft |
| 2 inches | 162 sq ft | 324 sq ft |
| 3 inches | 108 sq ft | 216 sq ft |
| 4 inches | 81 sq ft | 162 sq ft |
Coverage per 2 cu ft Bag:
| Depth | 1 Bag covers | 5 Bags cover | 10 Bags cover |
|---|
| 1 inch | 24 sq ft | 120 sq ft | 240 sq ft |
| 2 inches | 12 sq ft | 60 sq ft | 120 sq ft |
| 3 inches | 8 sq ft | 40 sq ft | 80 sq ft |
| 4 inches | 6 sq ft | 30 sq ft | 60 sq ft |
Coverage per Metric Bag (50L):
| Depth | 1 Bag covers |
|---|
| 25mm | ~2 m² |
| 50mm | ~1 m² |
| 75mm | ~0.67 m² |
| 100mm | ~0.5 m² |
Calculating for irregular areas
To calculate the volume of mulch for an irregular area, break the area down into smaller rectangles, triangles or circles. Calculate each one separately and add them together.
For circular areas (like around a tree), use the formula: Area = π × r², where r is the radius of the circle. For triangular areas: Area = ½ × base × height.
Mulch spreading and calculating weight
If you've ordered your mulch in cubic yards or cubic metres, but need to know how much your mulch weighs — perhaps for transportation purposes — here are some rough guidelines. Remember that the weight can change depending on the moisture content, with wet mulch being considerably heavier.
- Wood chip mulch: ~400-600 lbs per cubic yard (dry) / ~800 lbs (wet)
- Bark mulch: ~350-500 lbs per cubic yard
- Compost: ~500-800 lbs per cubic yard
- Rubber mulch: ~1200-1500 lbs per cubic yard
To convert cubic yards of mulch to weight, you multiply the volume by the density:
US Imperial example:
(yd³) × (lb) = (lbs). e.g. 2 × 400 = 800 lbs
UK metric example:
m³ × (kg/m³) = kg. e.g. 1.5 × 250 = 375 kg (0.375 tonnes)
How thick should mulch be?
Mulch is one of the staples of any garden. It not only makes the soil look more aesthetically pleasing, but it also helps with weed suppression, moisture retention and temperature regulation. But getting the depth right is important:
- Too thin (under 2"): Won't effectively suppress weeds or retain moisture. You'll see weeds popping through quickly.
- 2-3 inches: Ideal for most flower beds and around shrubs. Provides good weed suppression while allowing water penetration.
- 3-4 inches: Best for paths, play areas, and slopes where erosion is a concern.
- Over 4 inches: Generally too thick. Can suffocate plant roots, prevent water from reaching soil, and may attract pests. Also, mulch piled against tree trunks ("volcano mulching") can cause rot.
If you have any problems using our mulch calculator, please contact us.