One cubic yard of mulch equals 27 cubic feet
A cubic yard is a standard measurement unit used by mulch suppliers and landscapers. It measures 3 feet long by 3 feet wide by 3 feet deep. When you multiply those dimensions (3 × 3 × 3), you get 27 cubic feet. This is a fixed conversion—it never changes, regardless of the type of mulch or where you buy it.
Understanding this relationship matters because mulch is sold by the cubic yard, but you may need to calculate how much space it will cover in your garden beds, which is often measured in square feet. Knowing that one yard contains 27 cubic feet helps you work backward from your bed dimensions to figure out how many yards to order.
Key Takeaways
- One cubic yard of mulch always equals 27 cubic feet, no matter the mulch type or supplier.
- Mulch depth affects coverage: 27 cubic feet spread 2 inches deep covers 162 square feet, but spread 4 inches deep covers only 81 square feet.
- To find how many yards you need, measure your bed in square feet, decide on depth, then divide the cubic feet required by 27.
- Mulch settles over time, so ordering 10 to 15 percent extra accounts for settling and future top-ups.
How to calculate coverage from cubic yards
Start by measuring the square footage of the area you want to mulch. Measure the length and width of each bed in feet, multiply them together, then add all the beds together for your total square footage. For example, a bed that is 10 feet long and 4 feet wide is 40 square feet.
Next, decide how deep you want the mulch layer. Most landscapers recommend 2 to 4 inches. Once you know your square footage and desired depth, use this formula: (square feet × depth in inches) ÷ 324 = cubic yards needed. The number 324 comes from dividing 27 cubic feet by 12 inches.
Here is a practical example: if you have 200 square feet of bed space and want a 3-inch depth, the math is (200 × 3) ÷ 324 = 1.85 cubic yards. You would order 2 cubic yards to have enough, which equals 54 cubic feet.
Why depth matters when ordering mulch
The same 27 cubic feet of mulch covers different areas depending on how thick you spread it. At 2 inches deep, 27 cubic feet covers about 162 square feet. At 3 inches deep, it covers about 108 square feet. At 4 inches deep, it covers only about 81 square feet.
Thicker mulch layers suppress weeds better and retain moisture longer, but they also cost more because you need more material. A 2-inch layer is the minimum for weed control; 3 to 4 inches is ideal for moisture retention in hot climates. If you are unsure, 3 inches is a safe middle ground that balances cost and performance.
Accounting for settling and future maintenance
Mulch compacts and settles over the first few weeks after you spread it, especially if you water the beds. This settling can reduce the visible depth by 10 to 15 percent. To account for this, order slightly more than your calculation suggests—add 10 to 15 percent to your total.
You will also need to top up mulch each year as it breaks down and becomes part of the soil. Keeping a note of how many cubic yards you used makes it easier to order the right amount for maintenance. Many people find it helpful to order one extra cubic yard and store it in a dry spot for touch-ups throughout the season.
Converting between cubic yards and cubic feet in practice
If a supplier quotes you a price per cubic foot instead of per cubic yard, multiply the cubic foot price by 27 to compare it to a per-yard quote. For example, if mulch costs $2 per cubic foot, one cubic yard costs $54 (27 × $2). This makes it straightforward to shop around between suppliers who use different units.
Some suppliers also sell mulch by weight or by the bag. Bagged mulch is usually sold in 2 or 3 cubic foot bags. To figure out how many bags equal one cubic yard, divide 27 by the bag size. A cubic yard requires about 14 bags of 2 cubic foot mulch, or 9 bags of 3 cubic foot mulch. Bagged mulch costs more per cubic foot but works well for small projects.
Common mistakes when calculating mulch volume
The most common error is forgetting to convert inches to feet before calculating. If your bed is 10 feet long, 5 feet wide, and you want 3 inches of mulch, do not multiply 10 × 5 × 3. Instead, convert 3 inches to feet (3 ÷ 12 = 0.25 feet), then multiply 10 × 5 × 0.25 = 12.5 cubic feet. Divide by 27 to get 0.46 cubic yards.
Another mistake is underestimating the area you want to cover. Measure carefully and include any irregular shapes. If a bed has curved edges, break it into simpler shapes (rectangles and triangles) and add them together. It is better to overestimate slightly than to run short and have to place a second order.
Frequently Asked Questions
Does the type of mulch change how many cubic feet are in a cubic yard?
No. A cubic yard is always 27 cubic feet by volume, whether it is wood chips, shredded bark, or colored mulch. The type affects price, appearance, and how long it lasts, but not the volume measurement itself.
How do I measure a bed with an irregular shape?
Break the bed into straightforward shapes. Measure rectangles as length × width. For triangular sections, measure the base and height, then multiply and divide by 2. Add all the sections together for total square footage. This method works for curved beds too—just use more smaller sections.
Should I order more mulch than my calculation shows?
Yes, add 10 to 15 percent extra to account for settling. If your calculation shows 3 cubic yards, order 3.5 to 3.5 yards. This also gives you material for touch-ups later in the season as mulch breaks down.
Can I use this calculation for other materials like gravel or compost?
Yes. The cubic yard to cubic feet conversion (27 cubic feet per yard) works for any material sold by volume. However, gravel and compost may settle differently than mulch, so adjust your extra percentage based on the material type.
What if my supplier only gives me dimensions in inches?
Convert inches to feet first by dividing by 12. If a bed is 120 inches long and 60 inches wide, that is 10 feet by 5 feet, or 50 square feet. Then use the standard formula with your square footage and desired depth.