Outdoor & Landscape · Calculator
Mulch Calculator
Use this mulch calculator to find how many cubic yards or bags of mulch your beds need. Add rectangles, circles and odd shapes, choose a depth, and compare the cost of bulk mulch against 2 and 3 cubic foot bags.
Your beds
- Bed 1LengthftinWidthftin
Squares and rectangles.
80 sq ft - Bed 2Diameterftin
Measure straight across through the center.
50.3 sq ft
How to calculate how much mulch you need
Measure each bed, work out its area in square feet, and add them up. Multiply by the depth in inches and divide by 324 to get cubic yards. That 324 is simply 27 cubic feet in a yard times 12 inches in a foot.
Measure curved beds as simple shapes. A kidney-shaped bed is close to a rectangle plus a half circle. A ring around a tree is a circle, and you can subtract the trunk area if it is large. The calculator draws every shape to scale, so you can see if something looks off.
Bags are sold by volume, not weight. Big box stores sell 2 cubic foot bags; landscape suppliers often carry 3 cubic foot bags. Both are covered in the readout.
Recommended mulch depth
Most people buy too much mulch and pile it too deep. Here is the depth to aim for after the mulch settles.
| Mulch type | Depth | Notes |
|---|---|---|
| Shredded hardwood or bark | 2 to 3 in | The default for shrub and perennial beds |
| Wood chips (coarse) | 3 to 4 in | Paths and around trees, breaks down slowly |
| Pine straw | 2 to 3 in settled | Spread 3 to 4 in fluffed, it compresses fast |
| Fine mulch, compost, leaf mulch | 1 to 2 in | Packs down; too deep and it sheds water |
| Yearly top-up | 1 in | Rake the old layer first, then add |
| Vegetable beds (straw) | 2 to 4 in | Keep it off seedlings until they are established |
Do not build mulch volcanoes
Mulch coverage per yard and per bag
The coverage table works backward: if you know roughly how much ground you have, it tells you what one yard or one bag will do. One cubic yard covers 324 square feet at 1 inch, 162 at 2 inches, 108 at 3 inches and 81 at 4 inches.
A 2 cubic foot bag covers just 12 square feet at 2 inches. That is why a few beds can swallow 30 or 40 bags. Mulch also settles by 10 percent or more in the first weeks, so spread it a touch deeper than your target.
| Depth | 1 cu yd | 2 cu ft bag | 3 cu ft bag |
|---|---|---|---|
| 1 in | 324 sq ft | 24 sq ft | 36 sq ft |
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft |
Bags vs bulk mulch: where the break-even is
Bulk mulch almost always costs less per yard, but delivery fees change the math for small jobs. Fold the delivery fee into the price per yard, then divide by 13.5 to get what a 2 cubic foot bag would have to cost to match it.
- Under 1 yard: bags usually win, and they are easier to move around a finished yard.
- 2 yards and up: bulk wins in most markets, even with delivery. A full-size pickup holds about 2 yards if you can haul it yourself.
- Color-dyed mulch: bags are more consistent in color from one to the next. Bulk dyed mulch can vary by batch.
Tips for mulching like a pro
- Weed and edge first. Mulch slows new weeds; it does not smother established ones. Cut a clean edge so mulch does not wash into the lawn.
- Make your own. A wood chipper turns storm cleanup into free chips, and shredded leaves make excellent fine mulch.
- Skip landscape fabric under organic mulch. Mulch breaks down on top of it into a thin soil layer where weeds root anyway.
- Doing more of the yard? Fill low beds first with the topsoil calculator, price stone paths with the gravel calculator, and size new lawn with the sod calculator. The cubic yard calculator handles anything else by volume.
Keep it to 2 or 3 inches, keep it off the trunks, and let the mulch calculator do the bag math before you load the cart.
Frequently asked questions
How much area does a yard of mulch cover?
One cubic yard of mulch covers 162 square feet at 2 inches deep, 108 square feet at 3 inches and 81 square feet at 4 inches. The rule is 324 divided by your depth in inches.
How many bags of mulch are in a yard?
A cubic yard is 27 cubic feet, so it equals 13.5 bags of 2 cubic feet or 9 bags of 3 cubic feet. Round up to 14 of the smaller bags.
How deep should mulch be?
Spread 2 to 3 inches of shredded bark or wood chips in most beds. Use 1 to 2 inches for fine mulch or compost, and never more than 4 inches, which can starve roots of air. Keep mulch a few inches away from trunks and stems.
Should I remove old mulch before adding new mulch?
Usually no. Rake the old layer to loosen it, then add just enough new mulch to bring the total back to 2 to 3 inches. That is often only 1 inch a year. Remove it only if it is matted, moldy or piled too deep.
Is it cheaper to buy mulch in bags or bulk?
Bulk is usually cheaper once you need more than 1 to 2 cubic yards, even after a delivery fee. To compare, divide the bulk price per yard (including delivery) by 13.5. If a 2 cubic foot bag costs less than that, bags win.
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