Mulch and Gravel Calculator
A 10 ft by 10 ft bed covered 3 in deep takes 25 cubic feet, or 0.93 cubic yards. That is 13 bags of 2 ft³ mulch, or about 1.31 tons if it is gravel.
How to use
- Choose US units (feet and inches) or metric (meters and centimeters).
- Pick a rectangle or a circle and enter its size, then the depth you want to fill.
- Choose mulch, gravel, topsoil or sand. The density fills in a typical value that you can overwrite with your supplier's figure.
- Add an extra percentage for settling and waste, and pick a bag size. Read the volume, the weight and the number of bags.
How it works
Volume = area x depth. Rectangle area = length x width. Circle area = π x (diameter / 2)². Depth in inches is divided by 12 to get feet, and in centimeters by 100 to get meters. Total volume = volume x (1 + extra % / 100).
Weight = total volume x density. For a 10 x 10 ft bed 3 in deep, volume = 100 x 0.25 = 25 ft³ = 0.93 yd³. One cubic yard is 27 cubic feet, so one yard covers 324 sq ft at 1 in deep, 108 sq ft at 3 in and 81 sq ft at 4 in.
Bags = total volume / bag size, rounded up. Bag sizes are 2 ft³ (0.0566 m³), 3 ft³ (0.0850 m³) and 50 L (0.05 m³). A bag labeled in quarts or cubic feet is usually a little under its stated size once packed, so allow a bag or two extra.
Assumptions: the default densities are typical bulk values used by landscape suppliers, not a measured standard. Mulch 400 kg/m³ (about 0.34 ton/yd³), gravel 1,680 kg/m³ (about 1.42 ton/yd³), topsoil 1,250 kg/m³ (about 1.05 ton/yd³) and dry sand 1,600 kg/m³ (about 1.35 ton/yd³). Real values change with moisture, stone size and how packed the material is, often by 20% or more. Tons here are US short tons (2,000 lb); metric tonnes are 1,000 kg.
Default densities
| Material | kg/m³ | ton/yd³ (US) | lb/ft³ |
|---|---|---|---|
| Mulch (bark, wood chips) | 400 | 0.34 | 25 |
| Gravel (crushed stone) | 1,680 | 1.42 | 105 |
| Topsoil | 1,250 | 1.05 | 78 |
| Sand (dry) | 1,600 | 1.35 | 100 |
Coverage of one cubic yard
| Depth | Area covered |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
FAQ
How many cubic yards of mulch do I need?
Multiply the area in square feet by the depth in inches, then divide by 324. A 10 x 10 ft bed at 3 in deep is 100 x 3 / 324 = 0.93 cubic yards. Two to three inches is the usual mulch depth.
How many bags of mulch make a cubic yard?
One cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 ft³ or 9 bags of 3 ft³. In metric, 1 m³ takes 20 bags of 50 L.
How much does a cubic yard of gravel weigh?
Typically about 1.4 tons (2,800 lb) for crushed stone, but it ranges from about 1.3 to 1.7 tons with the stone type and moisture. Check your supplier's figure and enter it in the density box.
How deep should gravel and mulch be?
Mulch works best at 2 to 3 inches. Gravel paths and driveways are often 2 to 4 inches for a top layer, and more for a base. Thin layers let weeds through, and thick mulch against stems can cause rot.
Why add an extra percentage?
Loose material settles, edges are uneven and some is lost in handling. 5% to 10% extra is a common allowance. Set it to 0 for an exact volume.
Are tons here US tons or metric tonnes?
The weight row shows both. US tons are short tons of 2,000 lb (907 kg), and metric tonnes are 1,000 kg. In metric units the density box is in tonnes per cubic meter.