One yard of mulch covers 108 square feet at 3 inches deep
A cubic yard of mulch — the standard unit sold at garden centers and landscaping suppliers — covers roughly 108 square feet when spread 3 inches thick. This is the depth most gardeners use for weed suppression and moisture retention around plants and trees. If you spread the same yard only 2 inches deep, it covers about 162 square feet. At 4 inches deep, it covers 81 square feet.
The math is straightforward: a cubic yard contains 27 cubic feet. Divide 27 by the depth in feet, then multiply by 9 to convert to square feet. At 3 inches (0.25 feet), that gives you 108 square feet. The variation matters because thinner mulch dries out faster and lets weeds through more easily, while thicker mulch can trap moisture against the soil and rot plant stems if piled against them.
Key Takeaways
- One cubic yard of mulch covers 108 square feet at the standard 3-inch depth used for gardens and landscaping.
- Depth changes the coverage: 2 inches covers 162 square feet, while 4 inches covers 81 square feet from the same yard.
- Measure your bed length and width in feet, multiply them together, then divide by 108 to find how many yards you need at 3 inches deep.
- Mulch settles and compacts over time, so ordering 10 to 15 percent extra accounts for settling in the first few weeks.
- Delivery costs often depend on distance and load size, so buying in bulk (3 yards or more) is usually cheaper per yard than buying 1 or 2.
How to calculate the yards you need for your space
Start by measuring the length and width of each bed or area you plan to mulch, in feet. Multiply length times width to get square footage. If your bed is oddly shaped, break it into rectangles, calculate each one, and add them together. For a circular bed, measure the radius (distance from center to edge), multiply it by itself, then multiply by 3.14.
Once you have your total square footage, divide by 108 if you want 3 inches deep. For example, a bed that is 10 feet long and 8 feet wide is 80 square feet. Divided by 108, that is 0.74 yards — so you would order 1 yard. A larger bed of 20 by 15 feet is 300 square feet, which is 2.78 yards, so you would order 3 yards to have a little extra.
If you want a different depth, use this table to find your divisor:
| Depth | Divide square feet by this number |
|---|---|
| 2 inches | 162 |
| 3 inches | 108 |
| 4 inches | 81 |
| 5 inches | 65 |
Why depth matters for mulch performance
Three inches is the standard because it blocks most weed seeds from reaching soil while still allowing water and air to move through. Thinner mulch — 1 to 2 inches — dries out quickly in sun and does not suppress weeds as well, especially if you have persistent perennial weeds like bindweed or quackgrass. You will see weeds poking through within weeks.
Deeper mulch, 4 to 6 inches, works well around established trees and shrubs where you are not planting annuals. It keeps soil cooler and moister through dry spells. However, piling mulch against the base of a tree or shrub stem can trap moisture and cause rot. Leave a 2 to 3 inch gap around the stem itself, then mulch the rest of the bed.
Mulch also settles and compacts as it breaks down. A 3-inch layer will compress to about 2 inches within a few weeks. This is normal and not a sign you ordered the wrong amount. If you want to maintain 3 inches year-round, plan to add a fresh 1-inch layer each spring.
Accounting for settling and ordering extra
Garden centers and landscaping companies recommend ordering 10 to 15 percent extra to account for settling, spillage during delivery, and the fact that mulch is not perfectly uniform in density. If your calculation shows you need 5 yards, ordering 5.5 to 6 yards is reasonable. The extra mulch can go into a storage pile for top-ups later in the season.
Settling happens fastest in the first two to three weeks after delivery. You may notice the pile looks noticeably lower after rain or watering. This is the mulch compacting under its own weight and moisture. It is not a reason to panic or order more when ready — the coverage is still there, just denser.
Mulch types and how they affect coverage
Different mulch materials vary slightly in how they settle and compact. Hardwood mulch (made from shredded bark and wood) is denser and compacts more than softwood mulch (pine or fir). Shredded bark mulch is lighter and fluffier, so the same cubic yard may look like it covers more area when first spread, but it settles faster. Compost-based mulches are heavier and settle the most.
For coverage calculations, use 108 square feet per yard at 3 inches regardless of type — the variation between types is small enough that it does not change your order. What matters more is choosing a mulch type that suits your plants. Acid-loving plants like azaleas and blueberries do better with pine or fir mulch, while most ornamental beds do well with hardwood mulch.
Delivery and bulk pricing for mulch orders
Most garden centers and landscape suppliers charge by the cubic yard, with prices ranging widely depending on mulch type and your location. Delivery fees often depend on distance from the supplier and the total load size. Ordering 1 or 2 yards may cost more per yard than ordering 5 or 10 because the delivery truck is making a trip either way.
If you are ordering 3 yards or more, ask whether the supplier offers a bulk discount. Some will reduce the per-yard price at 5 yards or 10 yards. Bagged mulch from a garden center costs more per yard than bulk delivery but works for small beds under 100 square feet. A standard 2-cubic-foot bag covers about 8 square feet at 3 inches deep.
Common mistakes when ordering mulch
The most common error is underestimating square footage. Measure twice, especially if you are ordering for multiple beds. A 20-foot bed that you estimate as 15 feet will throw off your entire order. Use a measuring tape or a wheel measure if the bed is large.
Another mistake is ordering too little to avoid waste, then running out halfway through. It is better to have a small pile left over than to stop mid-project and wait for another delivery. Leftover mulch stores easily in a dry spot and can be used for top-ups or next year's beds.
A third error is spreading mulch too thick against plant stems and tree trunks. This creates a "mulch volcano" that traps moisture and invites rot and pest damage. Spread mulch in a flat layer, keeping it 2 to 3 inches away from any stem or trunk.
Frequently Asked Questions
How many bags of mulch equal one cubic yard?
A standard 2-cubic-foot bag equals about 0.074 cubic yards. One cubic yard requires roughly 13 to 14 bags of that size. Bag sizes vary, so check the label. Some suppliers sell 3-cubic-foot bags, which would require about 9 bags per yard.
Does mulch coverage change if I use colored or dyed mulch?
No. Colored mulch is standard mulch with added dye. It covers the same square footage per cubic yard as natural mulch at the same depth. The dye does not change the volume or settling rate significantly.
Can I mix mulch types to stretch my budget?
Yes. Mixing a cheaper mulch like pine with a more expensive hardwood mulch works fine and does not affect coverage. Blend them as you spread, or layer them — pine underneath, hardwood on top for appearance. The plants do not care about the mix.
What if my bed is sloped or uneven?
Measure the average depth you want across the bed and calculate based on that. For a sloped bed, you might aim for 3 inches at the low end and 4 inches at the high end, so use 3.5 inches as your target. This is close enough for ordering purposes.
How often do I need to add more mulch?
Top up with about 1 inch of fresh mulch each spring. This replaces what has broken down and settled over the year. You do not need to remove the old mulch first — just spread new mulch on top.