One cubic yard of mulch covers about 100 to 150 square feet at a 2-inch depth
The number of bags you need depends on three things: the size of your yard, how deep you want the mulch, and the bag size. Most bags sold at garden centers hold either 2 cubic feet or 3 cubic feet. A cubic yard equals 27 cubic feet, so one yard of mulch fills roughly 9 to 13 bags depending on bag size.
Start by measuring the area you want to cover in square feet. Then decide on depth—2 inches is standard for most landscaping, though some people go to 3 inches for better weed suppression. Once you know both numbers, you can calculate how many bags to buy without guessing or overbuy.
Key Takeaways
- One cubic yard of mulch covers 100 to 150 square feet at a 2-inch depth, depending on how densely you spread it.
- A 2-cubic-foot bag requires about 13 to 14 bags per yard; a 3-cubic-foot bag requires about 9 bags per yard.
- Measure your garden bed length and width in feet, multiply them together, then divide by the coverage number for your chosen depth.
- Buying one or two extra bags accounts for settling and uneven ground, which is cheaper than a second trip to the store.
How to measure the area you want to cover
Use a tape measure or a measuring wheel to find the length and width of each bed in feet. If your bed is irregular—curved edges or an L-shape—break it into rectangles, measure each one, and add the totals together.
Write down the total square footage. For example, a bed that is 10 feet long and 4 feet wide is 40 square feet. If you have three separate beds of 40, 50, and 30 square feet, your total is 120 square feet.
Calculating bags for a 2-inch depth
Two inches is the depth most landscapers recommend. It suppresses weeds, retains moisture, and looks finished without looking excessive. At this depth, one cubic yard covers 100 to 150 square feet depending on how firmly you pack it down.
Take your total square footage and divide it by 125 (a middle estimate). A 100-square-foot bed needs about 0.8 cubic yards. A 200-square-foot bed needs about 1.6 cubic yards. Round up to the nearest whole or half yard to avoid running short.
Once you have cubic yards, multiply by the number of bags per yard. For 2-cubic-foot bags, multiply by 13.5. For 3-cubic-foot bags, multiply by 9. A 100-square-foot bed at 2 inches deep needs roughly 7 bags of 2-cubic-foot mulch, or 5 bags of 3-cubic-foot mulch.
Calculating bags for a 3-inch depth
Three inches gives better weed control and lasts longer before settling, but it costs more and can look heavy in small spaces. At 3 inches, one cubic yard covers 65 to 100 square feet.
Divide your square footage by 80 (a middle estimate) to get cubic yards needed. A 100-square-foot bed needs about 1.25 cubic yards at 3 inches. Multiply by 13.5 for 2-cubic-foot bags (about 17 bags) or by 9 for 3-cubic-foot bags (about 11 bags).
Why bag size matters when you shop
A 2-cubic-foot bag is lighter and easier to carry, which matters if you are spreading mulch by hand. A 3-cubic-foot bag covers more ground per bag, so you make fewer trips and spend less on packaging. Check the price per cubic foot at your store—sometimes the larger bag is cheaper per unit, sometimes it is not.
Larger bags also take up more space in a vehicle. A cubic yard of mulch in 2-cubic-foot bags stacks into a pile about 4 feet tall and 3 feet wide. The same yard in 3-cubic-foot bags is more compact but heavier per bag.
Common mistakes that lead to buying too much or too little
The biggest mistake is not measuring—just guessing "a few bags" and running out halfway through. Measure once, calculate once, buy once. The second mistake is forgetting that mulch settles. After rain or a few weeks, it compacts by 10 to 20 percent, so buying one or two extra bags is worth the cost.
A third mistake is spreading too thin. One inch of mulch looks sparse and does not suppress weeds well. Stick to 2 to 3 inches. Finally, do not assume all bags labeled "mulch" are the same size—check the cubic footage on the bag itself, not just the brand name.
When to buy mulch in bulk instead of bags
If you need more than 5 cubic yards, bulk mulch from a landscape supply yard is usually cheaper than bags. You rent a truck or have it delivered, and you spread it yourself or hire someone to do it. Bulk mulch also comes in more varieties—hardwood, cedar, dyed—than what most garden centers stock in bags.
For small beds under 200 square feet, bags are simpler. For large yards or multiple beds totaling 300 square feet or more, call a local landscape supplier for a bulk quote. Many will deliver for a flat fee that pays for itself in savings.
Frequently Asked Questions
Do I need to remove old mulch before spreading new mulch?
Not always. If the old mulch is still in good shape and not compacted into a hard mat, you can spread new mulch over it. If it is matted, moldy, or more than 4 inches deep already, rake it out first. Spreading new mulch over old can create a barrier that water cannot penetrate.
How much does a bag of mulch weigh?
A 2-cubic-foot bag typically weighs 15 to 20 pounds. A 3-cubic-foot bag weighs 20 to 30 pounds. Wet mulch weighs more than dry mulch. Check the bag label for the exact weight, especially if you are loading many bags into a vehicle or carrying them by hand.
Can I use the same calculation for wood chips or bark?
Yes. Wood chips, bark, and shredded hardwood mulch all come in the same bag sizes and cover at the same rates. The calculation works for any loose mulch product sold by cubic feet or cubic yards.
What if my bed is oddly shaped or has curves?
Break it into straightforward shapes. Measure the length and width of each rectangle or triangle, calculate the area, and add them together. For a curved bed, estimate it as a rectangle slightly larger than the curve, then subtract a bit from your total. Buying one extra bag covers the margin of error.
Should I buy extra bags for settling?
Yes. Buy 10 to 15 percent more than your calculation suggests. Mulch settles after rain and over time, and you may have uneven ground that requires extra depth in spots. One or two extra bags is cheap insurance against a thin-looking yard in a month.