200 ft² bed at 3 in deep
- Input
- Area = 200 ft², Depth = 3 in
- Working
- Volume = 200 × (3 ÷ 12) = 50 ft³ = 50 ÷ 27 = 1.85 yd³. Bags = 50 ÷ 2 = 25 bags of 2 ft³.
- Result
- 1.85 yd³ = 25 bags of 2 ft³
Mulch Calculator
Calculate mulch volume from bed area and depth in cubic yards, cubic feet and standard bags — with a depth-to-coverage table for one cubic yard. Runs entirely in your browser — your numbers never leave this device.
System
Mulch volume (cubic yards)
1.85
Bulk mulch is usually sold by this measure.
- Volume (ft³)
- 50
- Bags (2 ft³ each)
- 25
Bag sizes vary by supplier — 2 ft³ bags (imperial) and 50 L bags (metric) are the common standards used here. A 3 in / 7–8 cm depth is typical for weed suppression without smothering plants.
How it works
Volume = area × depth | 1 yd³ = 27 ft³ | Standard bag = 2 ft³ (metric bag = 50 L)
| Depth | Area covered by 1 cubic yard |
|---|---|
| 1 in | 324 ft² |
| 2 in | 162 ft² |
| 3 in | 108 ft² |
| 4 in | 81 ft² |
Mulch is a volume: the area of the bed multiplied by the depth laid. The only care the multiplication needs is unit consistency — depth is usually chosen in inches against an area in square feet, so depth is converted to feet (or the area worked in square inches) before the two are multiplied. The result is expressed in cubic feet and cubic yards, since bulk mulch is sold by the yard and bagged mulch by the bag.
The coverage table inverts the same arithmetic for the common purchase question: one cubic yard spread 3 inches deep covers 108 ft², and the coverage halves or doubles as depth doubles or halves. Bag counts follow from the standard bag size — 2 ft³ in imperial, 50 litres in metric — with the count rounded up, because a part bag at the end of a bed still has to be bought and the last section laid thinner shows immediately.
Depths settle after laying and watering, and bagged volumes are nominal, so the figure is a planning estimate: it is the right basis for comparing a bulk load against bags and for ordering, with the expectation that a bed laid to an even depth may take slightly more or less than the arithmetic volume.
Worked examples
Metric: 20 m² at 7.5 cm deep
- Input
- Area = 20 m², Depth = 7.5 cm (0.075 m)
- Working
- Volume = 20 × 0.075 = 1.5 m³ = 1,500 L. Bags = 1,500 ÷ 50 = 30 bags of 50 L.
- Result
- 1.5 m³ = 30 bags of 50 L
100 ft² bed at 2 in deep
- Input
- Area = 100 ft², Depth = 2 in
- Working
- Volume = 100 × (2 ÷ 12) = 16.7 ft³ ≈ 0.62 yd³. Bags = 16.7 ÷ 2 = 8.35, rounded up to 9 bags.
- Result
- About 0.62 yd³ = 9 bags of 2 ft³
Frequently asked questions
How deep should the depth input be?
Enter the finished depth to be laid — the examples use 2 and 3 inches, the depths most beds are specified at. The coverage table shows the consequence directly: at 3 in a cubic yard covers 108 ft², at 2 in it covers 162 ft², so depth is the single biggest lever in the estimate.
Bulk load or bags — which does the estimate favour?
Neither; it reports both from the same volume. The first example's 1.85 yd³ is a small bulk load or 25 bags. The practical comparison is price per cubic foot in each form plus delivery, which the volume figures here make directly comparable.
Why round the bag count up?
Because bags are whole units and the volume is continuous. 8.35 bags of material cannot be bought; 8 bags leaves the last stretch of bed short, so the count is 9, as in the third example.
Does mulch volume change after laying?
Loose mulch settles and compacts after laying and watering, so a bed can sit slightly lower than its laid depth. The calculator works on laid volume; ordering to the arithmetic figure and keeping any spare bag for topping up is the normal planning approach.
Are measurements stored?
No. The calculation runs entirely in the browser and nothing entered is uploaded, stored or tracked.
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