Mulch Calculator for Tennessee Beds, Tree Rings and Sloped Borders
Enter your project dimensions
The thing this page has to fix most often is a unit. Someone works out their beds, looks at the three figures the tool returns, sees a tons number under half of one, and assumes the measurement went wrong somewhere. It did not. Shredded mulch is the lightest material sold here by a wide margin, about 600 lb a cubic yard on this site's published figures, and it is bought by volume. Read the cubic yards line and let the tons line alone.
How do I measure beds that curve around the house?
Beds hardly ever come out as tidy rectangles, and the way to handle that is to stop trying.
Break the run into straight lengths and measure each one at its average width. A foundation bed that pinches to two feet at the corner and swells to five in front of the porch is two measurements, not one. A bed with a curved front edge gets measured along its middle, not around the bulge. The tool takes Rectangle, Circle and Multiple areas, so up to five pieces can be totaled in one go, which covers most yards.
Two hypothetical runs along a house: 34 feet by 4 feet, and 18 feet by 5 feet. That is 136 plus 90, so 226 square feet. Topped up at 2 inches, 226 x 2 ÷ 12 = 37.7 cubic feet, and 37.7 ÷ 27 = 1.40 cubic yards. Round up to a yard and a half and you have the odd corner covered.
Two inches or three on beds that already have mulch under them?
Depth on this page is not a matter of taste, because the plants have an opinion.
Two inches is the figure for a top-up over an existing layer that is still loose. Three inches is for bare ground or a newly cut bed, where you need enough thickness to keep weed seed in the dark and hold moisture through a run of ninety-degree days in July. Four inches is the ceiling. Beyond that the layer starts holding water against roots and keeping air away from them, which does more harm in a humid summer than the weeds would have.
Rake last year's mulch open before you add to it. A matted layer sheds rain rather than letting it through, and adding fresh material on top of a crust just makes the crust thicker. If the old layer is matted or has a fungal mat through it, take it off and start at three inches.
Around a trunk, hold the mulch back three to six inches and keep the layer flat rather than heaped. Bark that stays wet against a trunk rots, and a mound at the base is an invitation to rodents. The same applies at the house: keep six inches of clearance from siding, stay below the slab line, and run only two to three inches deep in the last few feet, so a deep damp layer is not sitting against the wall.
Why does the tons line read so low?
Because the material is mostly air and shredded wood. At about 600 lb a cubic yard, mulch converts at roughly 0.30 tons a yard. The beds above came to 1.40 cubic yards, which is about 0.42 tons.
That figure is next to useless for ordering and quite useful for planning the day. Three yards of mulch is a pile about the size of a small car sitting on your drive, and it is light enough that one person with a wheelbarrow can shift it. Compare that with a yard of crusher run at around 3,000 lb, five times the weight in the same space, and you can see why one tool with one weight in it would get mulch wrong every time.
Bags are the other unit people arrive with. A cubic yard is 27 cubic feet, so it is 13.5 of the 2-cubic-foot bags sold at garden centers, or 9 of the 3-cubic-foot ones. The 1.40 yards above is about 19 bags, which is a lot of lifting and a lot of plastic for a bed run you could have tipped on the drive.
| Depth | 1 cubic yard covers | 10 bags of 2 cu ft cover |
|---|---|---|
| 1 in | 324 sq ft | 240 sq ft |
| 2 in | 162 sq ft | 120 sq ft |
| 3 in | 108 sq ft | 80 sq ft |
| 4 in | 81 sq ft | 60 sq ft |
Does the five percent box change a mulch order?
Hardly at all, and it is the wrong thing to lean on here anyway. The option adds five percent for compaction and spillage, which is aimed at material that gets rolled. Mulch is not compacted, so the depth you enter is the depth you finish with.
What does move the number is the beds you forgot. Almost everybody underestimates, and it is never the front borders, it is the strip behind the garage, the ring around the mailbox and the two feet down the side of the shed. Walk the whole property with the tape before you run the tool, and hold back the last half yard rather than spreading it thin, because a bed you find on Sunday afternoon is easier to cover from a reserve than from a second delivery.
Shredded, chip or dyed: does the yardage change?
No. Volume is volume, so the same bed at the same depth takes the same cubic yards whichever type you pick. What changes is how it behaves and how often you are back out there.
Shredded hardwood knits together as it settles, which is the reason it is the sensible default on a hill lot here. The fibers hook into each other and the layer stays put on a slope and through the kind of downpour that comes off a summer thunderstorm. Chips and nuggets last a season or two longer but they float, and on any bed with fall on it a heavy rain will carry them to the low end and out into the lawn. Dyed material holds its color longer and breaks down more slowly.
Play surfaces are the exception to the depth guidance above. Those want a playground-certified chip rather than landscape shred, at six inches or more, and the equipment manual sets the figure.
Working out a whole-yard refresh
Say the beds across a property come to 520 square feet. At the 2-inch top-up depth, 520 x 2 ÷ 12 = 86.7 cubic feet, and 86.7 ÷ 27 = 3.21 cubic yards. At 3 inches on bare ground the same beds take 520 x 3 ÷ 12 = 130 cubic feet, which is 4.81 cubic yards. An inch of depth across a modest yard is a yard and a half of material, so it is worth deciding the depth before you decide the order.
If the bed is being made rather than topped up, mulch is only the last layer of it. Size the garden soil that goes in first on the soil calculator, plant it, and bring the bark over the finished surface. A steep border that loses its cover every summer is the usual case for river rock instead.
Once you have the yardage, pick a quantity and a date on the shredded mulch product page. Delivery is arranged at checkout by ZIP code: the order is matched to a supplier in the network near that address, and an agent confirms the exact delivery address before the load goes out. Delivery access is a firm spot with clear room to tip.
Common questions
Where should three yards of mulch land on a hill lot?
On the flattest firm ground you have that is still uphill of most of the beds, so the loaded wheelbarrow runs go down. Put a tarp under it if the surface matters, since shredded mulch will stain fresh concrete, and spread it inside a week or two. A pile left standing for a month heats in the middle and turns sour, which you will smell before you see it.
The tool gives cubic yards and tons. Which do I use?
Cubic yards. Mulch is sold here by volume and the product page is priced that way, so the yards line is the one that matches. The tons figure is there because the same tool handles stone, and for mulch it is only worth a glance as a rough sense of what is landing on your drive.
Is the depth I enter before or after it settles?
It is the depth you spread, and for mulch the two are close enough not to matter. There is no rolling involved, so a 3-inch layer settles to something a little under 3 and stays there. What genuinely changes the figure is the state of the bed: bare soil takes 3 inches, an existing layer takes 2.
How do I enter a tree ring with a bare circle left around the trunk?
Run Circle mode twice and subtract. Four rings 6 feet across, each with a foot left clear at the trunk: 0.7854 x 36 = 28.3 square feet per ring, less 0.7854 x 1 = 0.8, so 27.5 each and 110 square feet for the four. At 3 inches that is 110 x 3 ÷ 12 = 27.5 cubic feet, almost exactly 1 cubic yard, or about 14 bags.
Can I check the result myself?
Square feet times depth in inches, divided by 12, then divided by 27. For bags, multiply the cubic yards by 13.5. Two hundred square feet at 3 inches: 200 x 3 ÷ 12 = 50 cubic feet, ÷ 27 = 1.85 cubic yards, which is about 25 bags.
Related calculators
Skip the 27-bag cart.
Bulk shredded hardwood by the yard, tipped in your driveway, delivery free.
