Mulch calculator
Voir le calcul — avec vos chiffres
These figures are arithmetic on the bed size you enter. Beds are rarely tidy rectangles and mulch settles, so keep a little waste in hand and treat the bag count as a shopping estimate.
Enter the size of the bed and how deep you want the mulch, and you get the volume in cubic yards and cubic metres plus the number of bags. The volume is length × width × depth; the bag count divides that by whatever one bag holds.
Exemple détaillé
A bed 20 ft long and 4 ft wide, mulched 3 inches deep: 3 inches is 0.25 ft, so the volume is 20 × 4 × 0.25 = 20 cubic feet, about 0.74 yd³. In 2 ft³ bags that is 10 bags; with 10% waste, order 11. Bulk would be roughly a single scoop under a yard — cheaper if you can haul it.
In metric: a 6 m × 1.2 m bed at 8 cm is 6 × 1.2 × 0.08 = 0.576 m³. In 50-litre bags that is 11.5 — buy 12; with 10% waste, 13.
Sur le chantier
A whole front yard of beds. Pace them: a 30 × 5 strip along the house, a 12 × 12 island, two 8 × 3 beds either side of the walk. That is 150 + 144 + 48 = 342 ft² at 3 inches: 342 × 0.25 = 85.5 ft³, which is 3.2 yd³ or 43 bags at 2 ft³. Three yards in bags is 43 trips from the truck — call the yard for a bulk drop and you handle it once with a barrow. (In metric: 32 m² of beds at 75 mm is 2.4 m³ — 48 bags of 50 L.)
Topping up, not starting fresh. Beds mulched last year usually want an inch, not three. Put 1 in the depth field and the same 342 ft² comes to 28.5 ft³ — a hair over a yard, 15 bags. Ordering three yards to "freshen up" is how you end up mulching the neighbour's beds too. In metric, 25 mm on those 32 m² is 0.8 m³, 16 bags of 50 L.
Bags by the pallet. If the store sells a pallet of, say, 45 bags at a discount, 45 × 2 ft³ = 90 ft³ = 3.33 yd³. Compare that to the bulk price for 3.5 yards delivered; the bulk yard usually wins on price and loses on your back. A pallet of 45 × 50 L bags is 2.25 m³.
What went wrong?
Quick referencefor beds
- A cubic yard
- 27 ft³ — 13.5 bags at 2 ft³, 9 bags at 3 ft³
- Depth as feet
- 1 in = 0,083 · 2 in = 0,167 · 3 in = 0,25 · 4 in = 0,333
- Bags from an area, at 3 in, 2 ft³ bags
- ft² ÷ 8
- Bags from an area, at 2 in, 2 ft³ bags
- ft² ÷ 12
- Yards from an area, at 3 in
- ft² ÷ 108
- Métrique
- 50 L bag = 0.05 m³ · 1 m³ = 20 bags of 50 L = 1.31 yd³
- Bags from an area, at 75 mm, 50 L bags
- m² × 1,5
Waste & overagewhat to add, and why
- Landscapers buy 10% over on bagged mulch and order bulk in whole yards — the pile settles a little as it lands, and the last barrow always comes up short at the far bed. The waste field starts at 10%.
- Bulk is cheaper past about two yards; a yard is 13.5 two-cubic-foot bags, so a 3-yard bed is 41 bags to carry.
Mistakes to catchbefore you order
- Spreading 3 in deep over a bed that was measured for 2 in — the depth field is the number to change when the customer wants more; the bag count moves with it.
- Measuring a curved bed as the rectangle around it; step it into a few rectangles or use the square footage page for a circle.
- Reading the bag count for 2 ft³ bags when the store sells 3 ft³ — set the bag size to what is on the shelf.
La formule
bags = (length × width × depth) ÷ volume per bag
Convert the depth from inches to feet, multiply out the volume in cubic feet, then divide by the cubic feet one bag holds. To read it in yards, divide the cubic feet by 27. Metric works in metres and litres — a 50-litre bag is 0.05 m³.
What this tool assumes
The depth, the waste and the bag size are all fields you can change, because they are what vary. There is no hidden "standard bag" — you tell it the bag you are buying and it counts them.
Questions
- How many bags of mulch are in a cubic yard?
- Thirteen and a half, when the bags hold 2 cubic feet each — a cubic yard is 27 cubic feet, and 27 ÷ 2 = 13.5. If your bags are 3 cubic feet it takes 9, and if they are 1.5 it takes 18. Set the bag size to match what is on the pallet and the count corrects itself. In metric, 50-litre bags go twenty to the cubic metre.
- How deep should I spread mulch?
- A depth of 2 to 3 inches (50 to 75 mm) is the usual range for a garden bed — enough to hold moisture and smother weeds without smothering roots. This tool covers whatever depth you type, so enter the depth you want and it works out the volume; it does not push a depth on you.
- Is bulk mulch cheaper than bags?
- Per cubic yard, bulk is almost always cheaper — you are not paying for the plastic or the bagging. Bags win only on small jobs where a yard is more than you need or you have no way to move loose material. The tool shows both the volume and the bag count so you can price it either way.
- Will one calculation cover an odd-shaped bed?
- Break the bed into rectangles, run each one, and add the volumes. A curved edge can be squared off to its average width without much error at mulch depths. For a rough bed, keep the 10% waste on — spreading is never perfectly even.
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