Mulch Calculator
Use this mulch calculator before you order bark, wood chips, compost or decorative mulch. Enter the bed length and width in feet, choose the depth in inches, and compare the result in cubic feet, cubic yards and 2 cu ft bag equivalents. The price fields are simple comparison fields, so you can use dollars or your local currency as long as you use the same currency for both bulk and bag prices.
How to calculate mulch quantity
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1
Measure the area
Measure length and width in feet. For curved or irregular beds, split the space into rectangles, calculate each section and add them together.
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2
Choose a sensible depth
Use 1 inch for a light top-up, 2 inches around established beds, 3 inches for weed suppression, and up to 4 inches around trees and shrubs. Keep mulch away from trunks and stems.
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3
Convert depth to volume
The calculator uses volume (cu ft) = length × width × (depth / 12), cubic yards = cu ft / 27, and 2 cu ft bags = ceil(cu ft / 2).
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4
Compare supply options
Enter the bulk price per cubic yard and the price per 2 cu ft bag. The totals help you decide whether bags, bulk delivery or a local litre-based product is the better buy.
How much mulch you actually need
Mulch math is mostly unit conversion. The tool keeps the calculation in the units it displays: feet for length and width, inches for depth, cubic feet, cubic yards and 2 cu ft bags. If your supplier sells by litres or cubic metres, use these quick conversions:
- 1 cubic yard = 27 cu ft = about 0.765 m³ = about 765 L
- 1 cu ft = about 28.3 L
- 1 bag of 2 cu ft = about 56.6 L
- 2 in = about 5 cm, 3 in = about 7.5 cm, 4 in = about 10 cm
Quick coverage reference at 3 inches deep
| Bed size entered | Area | Cubic feet | Cubic yards | 2 cu ft bags |
|---|---|---|---|---|
| 4 × 8 ft | 32 sq ft | 8 | 0.30 | 4 |
| 10 × 10 ft | 100 sq ft | 25 | 0.93 | 13 |
| 10 × 20 ft | 200 sq ft | 50 | 1.85 | 25 |
| 15 × 25 ft | 375 sq ft | 94 | 3.47 | 47 |
| 20 × 30 ft | 600 sq ft | 150 | 5.56 | 75 |
| 30 × 50 ft | 1,500 sq ft | 375 | 13.89 | 188 |
Metric ordering equivalents
| Local bed size | Typical depth | Volume | Approx. 2 cu ft bags | Approx. 50 L bags |
|---|---|---|---|---|
| 1.2 × 2.4 m border | 5 cm | 145 L | 3 | 3 |
| 2 × 3 m raised bed | 7.5 cm | 450 L | 8 | 9 |
| 3 × 5 m shrub bed | 7.5 cm | 1,125 L | 20 | 23 |
| 4 × 6 m tree ring or border | 10 cm | 2,400 L | 43 | 48 |
Depth guide by purpose
| Depth | Use |
|---|---|
| 1 in (2.5 cm) | Decorative top-up on an already mulched bed |
| 2 in (5 cm) | Established perennials, groundcover and annual maintenance |
| 3 in (7.5 cm) | Standard depth for weed suppression and moisture retention |
| 4 in (10 cm) | Wide rings around established trees and shrubs |
| 6 in+ (15 cm+) | Paths only, too deep for planted beds |
Keep mulch flat and pulled back from tree trunks, crowns and stems. Piling it into a mound traps moisture against bark, encourages rot and can damage roots.
Bulk versus bags
- Bulk cubic yard: Often cheaper for medium and large jobs, especially above 2 cubic yards. You need a delivery spot, a tarp and a wheelbarrow.
- 2 cu ft bags: Easier for balconies, small beds and car transport. One cubic yard equals 13.5 bags, so plan on 14 bags per cubic yard.
- Litre bags: In many markets, bark and mulch are sold in 40 L, 50 L, 60 L, 70 L or 100 L bags. Convert the calculator volume to litres, then divide by the bag size and round up.
- Break-even check: If bags are 5 each and bulk is 40 per cubic yard, bulk starts to win at about 8 bags. Delivery fees can move that point higher.
Material notes
- Bark or wood-chip mulch: The usual choice for ornamental beds, shrubs and tree rings.
- Compost or well-rotted organic mulch: Good for improving soil, but it settles faster than bark.
- Straw, pine needles or leaf mould: Often sold by bale or loose volume, so rely on coverage labels rather than cubic-yard pricing.
- Rubber or stone mulch: Does not decompose into the soil and can run much heavier than bark. Check the supplier weight limits before ordering.
Fresh organic mulch can settle by roughly 10-15% after watering and weathering. For a new display bed, order a little extra or plan a light top-up after the first few weeks.
Frequently Asked Questions
For most planted beds, 2-3 inches is enough. Use about 1 inch for a seasonal top-up and avoid going beyond 4 inches around living plants. Keep the mulch ring away from trunks and stems.
One cubic yard is 27 cubic feet. Divide by 2 and you get 13.5 bags, so buy 14 bags for each cubic yard if you are planning with 2 cu ft bags.
Yes. Calculate the job, multiply cubic feet by 28.3 to get litres, then divide by your bag size. A 2 cu ft bag is about 56.6 L, so it is close to a large 50-60 L bag.
Usually no. Organic mulch breaks down from the bottom, so most beds only need a light top-up each year. Remove and replace it only if it becomes matted, sour, mouldy or full of weed seed.
No. Your measurements are used only for the calculation in your browser session. They are not stored or shared.
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