CalculatorMulchThe bag says 12 square feet. At which depth?
Bag coverage
8 sq ft per bag at 3 in
one 2 cu ft bag, every depth people actually use
| Depth | One bag covers | Bags for 200 sq ft | In yards |
|---|---|---|---|
| 1 in | 24 sq ft | 9 | 0.62 yd |
| 1.5 in | 16 sq ft | 13 | 0.93 yd |
| 2 in | 12 sq ft | 17 | 1.23 yd |
| 3 in | 8 sq ft | 25 | 1.85 yd |
| 4 in | 6 sq ft | 34 | 2.47 yd |
| 6 in | 4 sq ft | 50 | 3.70 yd |
What the yard needs this month
MonthlyOne job a month, with the depth and the volume it actually needs. No plant catalogues, no upsell — just the material side of the garden.
Try also
How many square feet does a bag of mulch cover?
A 2-cubic-foot bag covers 24 square feet at 1 inch, 12 at 2 inches and 8 at 3 inches. Coverage is not a fixed number printed on the bag — it is the bag’s volume divided by the depth, and a bag that “covers 12 square feet” is quietly assuming 2 inches. Spread the same bag at the 3 inches most extension services recommend for beds and it covers a third less than the label suggested.
That is the single most common reason a mulching job runs short. Someone measures a 200-square-foot bed, reads 12 square feet on the bag, buys seventeen and lays them at a proper depth — and finds they have covered about 135 square feet with nothing left. The correct figure at 3 inches is 25 bags.
The arithmetic is one step: depth in inches divided by 12 gives feet, multiplied by the area gives cubic feet, divided by the bag size gives bags. Everything else on this page is that sum done ahead of time, for the depths and bag sizes that actually exist on a shelf.
What one bag covers, by depth
| Depth | 0.75 cu ft | 1 cu ft | 1.5 cu ft | 2 cu ft | 3 cu ft |
|---|---|---|---|---|---|
| 1 in | 9 sq ft | 12 sq ft | 18 sq ft | 24 sq ft | 36 sq ft |
| 2 in | 4.5 | 6 | 9 | 12 | 18 |
| 3 in | 3 | 4 | 6 | 8 | 12 |
| 4 in | 2.25 | 3 | 4.5 | 6 | 9 |
| 6 in | 1.5 | 2 | 3 | 4 | 6 |
The number on the bag is almost always the 2-inch row.
Bags for a 200 sq ft bed
| Depth | 1.5 cu ft bags | 2 cu ft bags | 3 cu ft bags | Cubic yards |
|---|---|---|---|---|
| 2 in | 23 | 17 | 12 | 1.24 |
| 3 in | 34 | 25 | 17 | 1.85 |
| 4 in | 45 | 34 | 23 | 2.47 |
Between 2 and 3 inches the order grows by half. It is worth deciding the depth before the trolley, not in the car park.
Related
For a bed measured in feet rather than a chart, the mulch bags calculator counts bags directly. To decide whether to buy bags at all, bulk vs bagged; to convert what you have into yards, bags to cubic yards.
Frequently asked questions
Why does the bag say a different number to this?
Because the bag has picked a depth and not told you which one. Most 2 cu ft bags quote 12 sq ft, which is 2 inches; some quote 8, which is 3 inches; and a few quote 24, which is 1 inch and flattering. The volume is the honest figure and it is always on the bag somewhere.
What depth should I actually use?
Three inches for beds and around shrubs, two around annuals and perennials you replant often, and four for paths and areas you want to stay clear. Deeper than four starts holding water against stems and keeping rain from the roots.
How many bags in a cubic yard?
Thirteen and a half at 2 cu ft, eighteen at 1.5, twenty-seven at 1 cu ft, and thirty-six at ¾ cu ft. It is worth knowing because it is how you compare a bag price against a bulk price — a $4.50 bag is a $61 cubic yard.
Do bag sizes differ between materials?
Yes, and it catches people out. Mulch is usually sold in 2 or 3 cu ft bags, compost and garden soil in 1 or 1.5, and potting mix in quarts or litres. A shelf of 1.5 cu ft compost bags next to 2 cu ft mulch looks identical from three feet away.
Should I buy extra?
Round up by about 10%. Beds are never perfectly rectangular, the last bag is never quite full, and a run to the garden centre for one bag costs more in fuel than the bag does.
At what point should I stop buying bags?
Around a cubic yard — thirteen or fourteen bags — is where bulk usually wins even after a delivery fee. The bulk vs bagged calculator works out the crossover for your own prices.
How we calculate this
Worked example
With Bag size 2 cu ft, Your bed area 200, this page works out 8 sq ft per bag at 3 in. one 2 cu ft bag, every depth people actually use
Sources:
The number the label leaves out
Coverage claims on bags are not dishonest so much as incomplete. A number in square feet has to assume a depth, the manufacturer picks a shallow one because it makes the bag look further-going, and the assumption is printed in small type if at all. The volume in cubic feet is the real specification and the only one you can calculate from.
It also explains why the same bed takes wildly different numbers of bags depending on who does the arithmetic. At 2 inches a 200 square foot bed takes 17 bags; at 3 inches it takes 25; at 4 inches it takes 34. Nobody is wrong — they are answering different questions, and the bag label picked one for you without saying so.