A yard of mulch covers about 100 to 110 square feet at a depth of 3 inches

One cubic yard of mulch is 27 cubic feet of material. When spread 3 inches deep — the standard depth for weed suppression and moisture retention — it covers roughly 100 to 110 square feet. The exact coverage depends on how densely you pack it and whether the mulch settles after you spread it.

If you need a different depth, the math shifts. At 2 inches deep, one yard covers about 160 square feet. At 4 inches deep, it covers roughly 80 square feet. Most landscapers recommend 3 inches as the sweet spot: deep enough to block weeds and hold moisture, but not so deep that it traps water against plant stems.

Mulch also compacts over time. Fresh mulch may cover 110 square feet, but after a few weeks of settling and rain, the same yard might cover only 90 to 95 square feet. Plan for this if you are ordering for a large bed.

Key Takeaways

  • One cubic yard of mulch at 3 inches deep covers approximately 100 to 110 square feet.
  • Coverage changes with depth: 2 inches covers about 160 square feet, while 4 inches covers about 80 square feet.
  • Mulch settles and compacts after spreading, so actual coverage may shrink by 10 to 15 percent within a few weeks.
  • A standard yard is 27 cubic feet, which you can calculate against your bed dimensions to estimate how many yards you need.

How to calculate mulch needed for your beds

Measure the length and width of each bed in feet, then multiply them together to get square footage. Add up all your beds. Divide that total by 100 to find how many yards you need at 3 inches deep.

Example: A bed that is 10 feet long and 5 feet wide is 50 square feet. A bed that is 8 feet long and 4 feet wide is 32 square feet. Together they are 82 square feet. Divided by 100, you need roughly 0.8 yards, or about one yard to account for settling.

If your beds are irregular shapes, break them into rectangles, calculate each one, and add them. For circular beds, measure the radius (the distance from the center to the edge), multiply it by itself, then multiply by 3.14 to get the area.

Why depth matters more than you think

Shallow mulch — less than 2 inches — does not block enough light to stop weed seeds from sprouting. Weeds still push through, and you spend the season pulling them. At 3 inches, most weed seeds cannot reach sunlight, so germination drops sharply.

Too deep, and mulch becomes a problem. Mulch piled 5 or 6 inches against a tree trunk or shrub stem traps moisture and can rot the bark. It also creates a home for insects and fungal growth. Aim for 3 inches away from the stem, then taper it down to nothing as you move outward.

Depth also affects how long mulch lasts. Thicker applications break down more slowly because the bottom layer stays drier and cooler. A 3-inch layer typically lasts one to two years before you need to top it off.

Different mulch types cover differently

Shredded hardwood mulch, the most common type, compacts more than wood chips. One yard of shredded mulch may cover 110 square feet, while one yard of larger wood chips might cover only 90 square feet because the chips do not pack as tightly.

Bark mulch is lighter and fluffier, so it covers more area per yard — sometimes 120 square feet at 3 inches. Dyed mulch is usually shredded fine and compacts well, giving you coverage close to hardwood.

Straw and hay are not true mulch but are sometimes used in vegetable gardens. They cover much more area per bale because they are so light and airy, but they break down faster and need replacing every season.

How to order the right amount

Calculate your square footage, divide by 100, then round up. If you get 2.3 yards, order 3. Mulch is cheaper by the yard when you buy in bulk, and leftover mulch keeps for a year or two if stored dry.

Many landscape suppliers sell mulch by the yard and deliver for a fee. Some offer bulk discounts at 5 yards or more. A few sell bags of mulch for small projects — a typical bag is 2 to 3 cubic feet, so you would need 9 to 13 bags to equal one yard.

If you are picking up yourself, bring a truck or trailer. One yard of wet mulch weighs 400 to 600 pounds depending on the type and moisture content. Damp mulch is heavier than dry mulch.

Settling and maintenance over time

Fresh mulch looks full and fluffy. Within two weeks, rain and foot traffic compress it. Within a month, it may have settled 10 to 15 percent, so that 110-square-foot coverage drops to 95 square feet. This is normal.

Each year, mulch breaks down and becomes part of the soil. You lose about one-third to one-half of your mulch depth annually, depending on climate and mulch type. In hot, wet climates, breakdown is faster. In cool, dry climates, it is slower.

Plan to top off beds every one to two years with a fresh 1 to 2 inches. This keeps the depth at 3 inches and maintains weed suppression. Topping off is cheaper than replacing all the mulch.

Common mistakes when estimating coverage

The biggest mistake is ordering too little and running short halfway through. It is hard to match the color and texture of mulch from a second delivery, and you end up with visible seams in your beds. Order 10 to 15 percent extra.

Another mistake is spreading mulch too thin, thinking you will save money. Thin mulch does not suppress weeds, so you spend the summer fighting them. The money you save upfront costs you in labor later.

A third mistake is piling mulch against tree trunks and shrub stems. This causes rot and invites pests. Keep mulch 3 to 6 inches away from any woody stem, and slope it away gently.

Frequently Asked Questions

How many bags of mulch equal one yard?

A standard bag of mulch is 2 to 3 cubic feet. One yard is 27 cubic feet, so you need 9 to 13 bags depending on bag size. Bags are convenient for small projects but cost more per cubic foot than bulk mulch delivered by the yard.

Does mulch coverage change if I use a different color?

Color does not affect coverage. Dyed mulch and natural mulch of the same type cover the same area per yard. Dyed mulch is usually shredded finer, so it may compact slightly more, but the difference is small.

Can I use less than 3 inches of mulch and still stop weeds?

Two inches can suppress some weeds, but three inches is more reliable. At two inches, determined perennial weeds and seeds from nearby plants still push through. Three inches blocks most light and is worth the extra cost.

What if I spread mulch too thick by accident?

Rake some away from tree trunks and shrub stems when ready. If the entire bed is too thick, you can rake it thinner or wait for it to settle. Do not leave thick mulch against woody plants — it will cause rot and pest problems.

How long does one yard of mulch last?

At 3 inches deep, one yard typically lasts one to two years before settling and breakdown reduce it noticeably. In hot, wet climates, it breaks down faster. You will need to top it off annually to maintain 3 inches of coverage.