Solve backwards
How big a bed will my bags of mulch cover?
- 20 bagsThe example worked below
- Mulch CalculatorEvery figure is its own
You have
How much bagged mulch?
Worked by the Mulch Calculator at the settings below.
The settings it uses
- Mulch depth
- 3 in
- Bag size
- 2 ft³ bag (56.6 L) — US/CA
What it will do
160 sq ft of bed
14.9 m²
One garden bed. Enough for a garden bed about 12.6 × 12.6 ft.
Or several. Less than one garden bed of the size the Mulch Calculator opens on (a garden bed about 14.8 × 14.8 ft).
Check it forwards
- Bed area
- 160 sq ft
- It asks for
- 20 bags
- You have
- 20 bags
The Mulch Calculator asks for 20 bags at that size, and 21 bags one step larger.
If you had more, or less
Around your amount
Each worked by the Mulch Calculator at the same settings.
Half
10 bags
80 sq ft
a garden bed about 8.9 × 8.9 ft
Yours
20 bags
160 sq ft
a garden bed about 12.6 × 12.6 ft
Half as much again
30 bags
240 sq ft
a garden bed about 15.5 × 15.5 ft
Double
40 bags
320 sq ft
a garden bed about 17.9 × 17.9 ft
Common amounts
What each amount of bagged mulch covers
The sizes it is usually sold in, each worked by the Mulch Calculator at the settings above.
| You have | It covers | As one garden bed | Average garden beds |
|---|---|---|---|
| 10 bags | 80 sq ft(7.43 m²) | a garden bed about 8.9 × 8.9 ft | under 1 |
| 20 bags | 160 sq ft(14.9 m²) | a garden bed about 12.6 × 12.6 ft | under 1 |
| 50 bags | 400 sq ft(37.1 m²) | a garden bed about 20 × 20 ft | 1 |
| 100 bags | 800 sq ft(74.3 m²) | a garden bed about 28.3 × 28.3 ft | 3 |
Depth decides the answer
The calculator opens at 75 mm, about 3 inches — inside the 75 to 100 mm (3 to 4 in) that suppresses weeds and holds moisture. Thinner than 50 mm (2 in) and weeds come through; thicker than 100 mm and roots can go short of air on a heavy soil. Halve the depth and the same bags cover twice the bed.
Bag sizes are not standard
Bagged mulch is commonly sold in 2 cubic foot bags (56.6 litres) in North America and in 50 to 70 litre bags elsewhere, and the page counts the bag your market usually sells. Volumes differ between suppliers by enough to change a large bed noticeably, so read the bag — and over a fairly modest quantity, a bulk delivery costs less than the same volume bagged.
Mulch settles and rots down
No settlement allowance is added: the bed here is the layer as spread. Organic mulch consolidates under rain and feet and then loses depth as it breaks down, so a bed that measures right on the day reads shallower by the end of the season. When topping up, count only the depth you are adding, not the finished depth you want.
How the answer is worked
Nothing here is a second formula. The Mulch Calculator runs forwards — a size in, a quantity out — and this page grows its own starting garden bed in proportion until the quantity it asks for is what you have. Where it rounds up to whole containers, the answer is the largest size before the next one would be needed.
Where the calculator adds an allowance for cuts or breakage when you order, the same allowance comes off here, because it is the same calculator: a stack you already own finishes less than its face value. Where it adds none, neither does this page — the settings beside the answer say which.
Mulch Calculator
runs it forwardsWork out how many bags, cubic yards or cubic metres of mulch a bed needs, at the depth that actually suppresses weeds.
Work out what to buy insteadSolve backwards
Other things you might already have
How much bed will a yard of mulch cover?
Bulk mulch, worked by the Mulch & Gravel Calculator.
How much ground will my gravel cover?
Gravel, worked by the Mulch & Gravel Calculator.
How big a bed will my topsoil fill?
Topsoil, worked by the Topsoil Calculator.
How big a raised bed will my soil fill?
Raised bed soil, worked by the Garden Soil Calculator.
How much ground will my compost dress?
Compost, worked by the Compost Blend Calculator.
How big a slab will a yard of concrete pour?
Ready-mix concrete, worked by the Concrete Calculator.
Solve backwards
Start from what is already in the yard
Paint, sheets, rolls, bags and pieces, each read the other way by the calculator that orders it.
The calculator's own figures
Nothing is estimated twice: the page runs the same calculator you would order with.
The largest size that fits
Where a calculator rounds up to whole containers, the answer stops before the next one.
Both unit systems
Gallons and litres, square feet and square metres, side by side.
Frequently asked questions
- How much bed does 20 bags of bagged mulch cover?
- At the Mulch Calculator's own settings, 160 sq ft (14.9 m²) — a garden bed about 12.6 × 12.6 ft. Every figure follows the settings, which you can change in the calculator.
- How many square feet does a 2 cubic foot bag of mulch cover?
- At 3 inches deep, a 2 cubic foot bag covers 8 square feet (about 0.74 m²); at 2 inches, 12 square feet. Twenty bags at 3 inches cover about 160 square feet (15 m²). Depth moves the answer far more than anything else, so decide it first.
- How deep should mulch be?
- Around 3 to 4 inches (75 to 100 mm) for weed suppression and moisture, according to university extension horticulture guidance. Less than 2 inches (50 mm) lets weeds through; much more than 4 inches can starve roots of air on heavy soil. Keep it pulled back a hand's width from trunks and stems.
- Is bulk mulch cheaper than bags?
- Usually, above a fairly modest quantity — often a single large border rather than a whole garden. Bulk is sold by the scoop or cubic yard with a delivery charge, so price the same volume both ways; the bulk mulch page reads a delivered load the same way this one reads bags.