- Buying Guide
- Mulch
How Much Mulch Do I Need? Calculate Cubic Yards for Your Beds
A simple square-footage formula, a coverage chart, and the right depth for mulch in Norman, OK.
Buying too little mulch means a second trip. Buying too much means a pile sitting in your driveway. The good news: figuring out how much mulch you need comes down to one quick measurement and a little math. Here is how to get it right the first time.
The one formula you need
Mulch is sold by the cubic yard, so you need to turn your flat bed into a volume. Measure each bed in feet, pick your depth, and use this:
(Length in feet) x (Width in feet) x (Depth in inches) ÷ 324 = cubic yards
The 324 is just the number that converts square feet and inches into cubic yards, so you do not have to think about it. A 20 foot by 10 foot bed at 3 inches deep works out to 20 x 10 x 3 = 600, divided by 324, or about 1.9 cubic yards.
For an odd-shaped bed, break it into rectangles, figure each one, and add them together. Round up to the nearest quarter yard when you order.
Quick coverage chart
If you would rather skip the math, one cubic yard of mulch covers roughly this much ground:
| Depth | Coverage per cubic yard |
|---|---|
| 2 inches | about 160 sq ft |
| 3 inches | about 100 sq ft |
| 4 inches | about 80 sq ft |
So if you have 300 square feet of beds and want 3 inches of mulch, you need about 3 cubic yards.
How deep should you go?
For most Oklahoma beds, 2 to 3 inches is the sweet spot. That holds moisture through our summers and blocks weeds without smothering plant roots or holding water against stems.
A useful rule: top up with about an inch of fresh mulch each spring rather than adding a thick new layer every year. Old mulch breaks down and feeds the soil, and piling it too deep can starve roots of air.
Around trees, keep mulch a couple inches back from the trunk. The "mulch volcano" piled against the bark traps moisture and invites rot.
Bulk vs. bags
One cubic yard equals about 13.5 standard bags (the 2 cubic foot size). Once you are covering a full bed or two, bulk mulch by the yard is cheaper, faster to spread, and means fewer plastic bags to haul off. For a small container or a single shrub, a bag or two is fine.
Ready to order?
Measure your beds, run the numbers, and round up a little. Then take a look at our full mulch selection, from cedar and pine bark to colored and natural mulch, and give us a call. Tell us your cubic yards and we will load you up or deliver it to your door. Not sure on your total? Reach out with your bed sizes and we will help you figure it out.
People Also Ask
Common Questions About This Topic
How many square feet does a cubic yard of mulch cover?
One cubic yard of mulch covers about 100 square feet at 3 inches deep, roughly 160 square feet at 2 inches, or about 80 square feet at 4 inches. Depth is the biggest factor, so decide how deep you want the mulch before you order.
How do I calculate cubic yards of mulch?
Multiply the bed length by the width in feet to get square feet, multiply by the depth in inches, then divide by 324. For example, a 20 by 10 foot bed at 3 inches deep is 20 x 10 x 3 = 600, divided by 324, which is about 1.9 cubic yards.
Is it better to buy mulch in bulk or in bags?
For anything more than a few bags, bulk by the cubic yard is cheaper and less waste. One cubic yard equals about 13.5 of the standard 2 cubic foot bags, so bulk pays off fast once you are covering a full bed or two.
How deep should mulch be?
Two to three inches is right for most Oklahoma beds. That is enough to hold moisture and block weeds without smothering roots. Refresh with an inch or so each year rather than piling new mulch on thick.
