Mulch, soil and gravel calculator
Work out how much mulch, topsoil, compost or gravel you need for your beds and borders, in cubic yards and bags.
You need
- Cubic feet
- Bags
- Weight (estimate)
Estimates only.
How this calculator works
Add each area you want to cover, as a rectangle (length and width) or a circle (diameter), and choose the depth in inches. The calculator works out the volume in cubic feet, converts it to cubic yards (27 cubic feet each) and tells you how many bags to buy in the size you choose.
For gravel, it also estimates the weight in tons, since gravel is often sold by the ton. Gravel weight varies by type, so check with your supplier.
Typical depths
| Material | Depth |
|---|---|
| Mulch in beds | 2 to 3 inches |
| Compost as a top dressing | 1 to 2 inches |
| Topsoil to level or fill low spots | 2 to 4 inches |
| Gravel path | 2 to 3 inches over a compacted base |
Tips
- Measure each bed separately and add them together; odd shapes can be split into rectangles and circles.
- Buy a little extra, about 5 to 10%, since materials settle.
- Pull weeds and water first, then spread mulch on damp soil.
Common questions
About 2 to 3 inches for most beds. Thinner layers don't stop weeds well, and deeper layers can starve roots of air. Keep mulch a few inches away from tree trunks and plant stems.
For more than about 2 or 3 cubic yards, bulk is usually much cheaper, though delivery fees apply. Bags are easier for small areas and if you can't store a pile.
A cubic yard is 27 cubic feet, so it's about 13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet.