How the mulch calculator works
Landscape materials are sold by volume (bags in cubic feet, bulk in cubic yards) or, for stone and sand, by weight. The calculator finds the volume of your bed or path and converts it into each way you can buy.
Cubic feet = area (sq ft) × depth (in) ÷ 12
Cubic yards = cubic feet ÷ 27
Bags = cubic feet ÷ bag size, rounded up
Tons = cubic yards × weight per cubic yard
Worked example
A 20 by 10 foot flower bed is 200 sq ft. At 3 inches deep that is 50 cubic feet, or 1.85 cubic yards. In 2 cu ft bags that is 25 bags; in bulk, order 2 yards.
Recommended depths
| Use | Depth |
|---|---|
| Mulch on garden beds | 2 to 3 in |
| Mulch for playground areas | Much deeper; follow playground safety guidance for your fall height |
| Topsoil over a lawn to level it | 1/4 to 1/2 in at a time |
| Topsoil for a new lawn or bed | 4 to 6 in |
| Gravel walking path | 3 to 4 in |
| Gravel base under a patio or shed | 4 to 6 in, compacted |
| Sand bed under pavers | About 1 in |
Weights used
Stone and sand are heavy, and suppliers often price them by the ton. The calculator uses these typical figures; actual weight varies with stone type and moisture.
| Material | Weight per cubic yard | Common bag |
|---|---|---|
| Mulch | Light; sold by volume | 2 cu ft |
| Topsoil | About 1.1 tons | 0.75 cu ft |
| Gravel | About 1.4 tons | 0.5 cu ft |
| Sand | About 1.35 tons | 0.5 cu ft |
Measuring beds and paths
- Rectangular beds: measure length and width.
- Round tree rings: choose Circle and enter the diameter. Subtract the trunk with a small circle cut-out if it is large.
- Curved or kidney-shaped beds: break them into a rectangle plus half-circles or triangles, or measure the longest length and average width.
- Paths: total length by width. Add each branch as its own section.
Before you buy
- Bulk deliveries usually have a minimum order and a delivery fee; ask before comparing with bag prices.
- Have the delivery dumped on a tarp near where you need it to save wheelbarrow trips.
- Check your vehicle's payload before hauling gravel or sand yourself. One cubic yard of gravel is well over a ton.
Common questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet. That is 13.5 bags of 2 cu ft mulch, or 9 bags of 3 cu ft.
How deep should mulch be?
2 to 3 inches works for most garden beds. Thinner layers let weeds through; much deeper layers can keep roots too wet. Keep mulch pulled back a few inches from tree trunks and stems.
How much does a cubic yard of gravel weigh?
Roughly 1.3 to 1.5 tons depending on the stone and moisture. The calculator uses 1.4 tons. Suppliers often sell gravel by the ton, so ask them for their own figure.
Is bulk mulch cheaper than bags?
Usually, once you need more than about 2 cubic yards. Bulk prices are per yard plus a delivery fee, so small jobs can still be cheaper in bags.
How much topsoil do I need for a raised bed?
Multiply the bed's length by width in feet and by the depth in inches divided by 12. A 4 by 8 foot bed filled 10 inches deep holds about 26.7 cubic feet, close to 1 cubic yard. Many gardeners fill raised beds with a soil and compost blend rather than plain topsoil.