Mulch calculator
Measure each bed, choose a depth, and this works out the mulch in cubic yards for a bulk delivery and in bags for the store, with the working shown under the answer. Beds can be rectangles or circles, and you can add as many as the job has. Then Add to an estimate puts the mulch on a free estimate as a line, ready to price and send. Nothing leaves your browser.
The working: 240 sq ft × (3 in ÷ 12) = 60 cu ft. ÷ 27 = 2.22 yd³. × 1.05 = 2.33 yd³. 63 cu ft ÷ 2 cu ft per bag = 32 bags, rounded up.
How the mulch math works
Area times depth gives volume. Multiply the bed’s length by its width for square feet (for a round bed around a tree, 3.1416 × the radius squared), multiply by the depth in inches divided by 12, and you have cubic feet. Bulk mulch is sold by the cubic yard, which is 27 cubic feet, so divide by 27. Bags are sold by the cubic foot, so divide the cubic feet by the bag size and round up.
For a 12 × 20 ft bed at 3 inches: 240 sq ft × 0.25 ft = 60 cubic feet, which is 2.22 cubic yards or 30 bags of 2 cu ft. Add 5% for settling and uneven ground and it becomes 2.33 yards or 32 bags. Shredded mulch packs down after the first rain, which is why a small allowance is normal.
| Depth | Sq ft per cubic yard | Sq ft per 2 cu ft bag |
|---|---|---|
| 1 in | 324 | 24 |
| 2 in | 162 | 12 |
| 3 in | 108 | 8 |
| 4 in | 81 | 6 |
How to measure beds
- Measure each bed separately and add it as its own area. Curved borders are easier to estimate as a rectangle a little smaller than the bed’s outer edge.
- For a ring around a tree, measure the diameter of the ring you want to mulch. The trunk takes up so little of it that it can be ignored.
- Subtract nothing for shrubs and perennials unless they are large; mulch goes between and under them.
- Check what is already there. Two inches of old mulch in good shape needs a topping up, not a full depth.
Typical mulch depths
These are the depths commonly recommended for organic mulch; finer material can go a little thinner and coarse chips a little deeper.
| Use | Typical depth |
|---|---|
| Topping up existing beds | 1–2 in |
| Planting beds and borders | 2–3 in |
| Ring around a tree (kept off the trunk) | 2–4 in |
| Paths through beds, wood chips | 3–4 in |
Playground surfacing is a different thing: it is a safety surface with depths set by fall height, not a garden mulch. Follow the U.S. Consumer Product Safety Commission’s public playground guidance and the product maker’s figures for that, not this table.
Ordering tips
- Bulk or bags. Above two or three yards, bulk is usually cheaper per cubic foot. Below that, or where the beds are behind the house, bags can win on labor.
- Delivery fees and minimums are common for bulk. Ask before you split a job across two drops.
- Color and type vary by batch and supplier. On a big job, order it all at once so the beds match.
- Bag sizes are printed on the bag; 2 cu ft is the most common in the US, but 1.5 and 3 cu ft bags are sold too. Change the bag size in the calculator to match.
Putting the mulch on an estimate
Add to an estimate takes the result straight into the estimate generator as a line that says what the customer is getting: the mulch, the yards or bags, the area and the depth. Choose whether the line is priced per yard or per bag, and type a unit price if you have it; everything stays editable once it is there.
If you have set up your business, the estimate opens on it. If not, it opens on the landscaping sample, and the sample’s own lines stay out unless you tick the box. Put delivery, edging, bed prep and spreading on lines of their own — they are labor, and a customer comparing two quotes wants to see where the money goes. The landscaping estimate template starts with those lines written. For stone instead of bark, use the gravel calculator, which adds tons.
Questions about mulch
How many bags of mulch make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 13.5 bags of the common 2 cu ft size — call it 14, since bags are not sold in halves. With 3 cu ft bags it is 9 bags, and with 1.5 cu ft bags, 18. Check the bag: the volume is printed on it, and sizes vary by brand.
How much area does a yard of mulch cover?
Divide 324 by the depth in inches. One cubic yard covers about 162 sq ft at 2 inches, about 108 sq ft at 3 inches and about 81 sq ft at 4 inches. A single 2 cu ft bag covers about 12 sq ft at 2 inches deep, or 8 sq ft at 3 inches.
How deep should mulch be?
Two to three inches is the typical depth for planting beds, enough to hold moisture and smother weed seedlings without starving roots of air. Topping up last year’s mulch usually takes an inch or so. Keep it pulled back a few inches from tree trunks and plant stems rather than piled against them.
Is bagged or bulk mulch cheaper?
For more than a couple of yards, bulk delivered by the yard is usually cheaper per cubic foot, even with a delivery fee — but it arrives as a pile in the driveway that has to be moved by wheelbarrow. Bags cost more per cubic foot and are easier to carry to a back bed. Price both from your local supplier; the calculator gives the quantity for each.