Mulch Calculator
Bags & cubic yards of mulch for your beds
Refreshing your beds? Enter the bed size and depth to find the number of 2 ft³ bags, or the cubic yards to order in bulk. Below: how far a yard goes, the bag conversions people search for constantly, whether it fits in a pickup, and the mulching mistake that kills trees.
How much mulch do I need, and how deep?
2 to 3 inches is the sweet spot — deep enough to suppress weeds and hold moisture, shallow enough that air and water still reach the roots. Going deeper is not more protective; past about 4 inches mulch starts working against you, holding water against stems and keeping oxygen out.
| Depth | Cubic yards | 2 ft³ bags | Suits |
|---|---|---|---|
| 1 in | 0.32 yd³ | 5 | Topping up an existing layer |
| 2 in | 0.65 yd³ | 9 | Annual refresh, fine mulch |
| 3 in | 0.97 yd³ | 14 | New beds, weed suppression |
| 4 in | 1.30 yd³ | 18 | Coarse nuggets, paths |
| 6 in | 1.94 yd³ | 27 | Too deep for planted beds |
If the same job also needs soil or stone, the printable material coverage chart lists mulch, topsoil, gravel and sand coverage side by side, with the bag-to-yard conversions underneath.
How many bags is a yard of mulch?
Mulch coverage per yard is fixed by depth, so the conversions below never change.
13.5 bags, since a cubic yard is 27 ft³ and a standard bag holds 2 ft³. In practice you buy 14. This is the single most searched conversion on this page, so here is the full set:
| Bulk | 2 ft³ bags | Covers at 2 in | Covers at 3 in | Weight |
|---|---|---|---|---|
| ½ yard | 7 | 81 ft² | 54 ft² | 270 lb |
| 1 yard | 13.5 | 162 ft² | 108 ft² | 540 lb |
| 2 yards | 27 | 324 ft² | 216 ft² | 1,080 lb |
| 3 yards | 41 | 486 ft² | 324 ft² | 1,620 lb |
| 4 yards | 54 | 648 ft² | 432 ft² | 2,160 lb |
Working backwards is just as useful: 20 bags covers about 160 ft² at 3 inches, or 240 ft² at 2 inches.
Bags or bulk?
Bags run roughly $3 to $6 each, so a cubic yard in bags is $40 to $81. Bulk mulch is commonly $30 to $50 per cubic yard plus delivery. The crossover is around 10 to 12 bags, and past that bulk wins on price, on plastic waste, and on the tedium of splitting bags open.
The practical question is whether it fits in your vehicle. Mulch is light — about 540 lb per cubic yard, a quarter of what topsoil weighs — so weight is rarely the limit; volume is. A standard 6-foot pickup bed holds about 2 cubic yards level with the sides, and 3 if you can heap it. Four yards needs two trips or a delivery. A small trailer or an SUV with seats down manages half a yard at best.
Wood, bark or dyed?
| Type | Lasts | Best for | Watch out |
|---|---|---|---|
| Shredded hardwood | 1 to 2 years | Slopes, general beds | Can mat and shed water |
| Bark nuggets | 2 to 3 years | Flat beds, around shrubs | Floats away in heavy rain |
| Dyed mulch | 1 to 2 years | Colour retention | Often recycled wood; check the source |
| Pine straw | 1 year | Acid-loving plants, slopes | Light, blows around |
| Cedar or cypress | 2 to 3 years | Insect resistance | Costlier |
| Wood chips (arborist) | 1 to 2 years | Paths, tree rings | Often free, but variable |
Fresh, undyed wood chips are sometimes said to steal nitrogen from plants. That effect is real only in the top fraction of an inch where wood meets soil, so it matters for a seedbed and essentially not at all for established shrubs and trees with mulch on the surface.
The mulch volcano, and the 3-3-3 rule
The most damaging mulching habit is piling it into a cone against a tree trunk. Bark is not built to sit wet: constant moisture against the trunk rots the bark, invites insects and disease, and encourages roots to grow into the mulch and circle the trunk, eventually strangling the tree. It takes years and it is usually fatal.
3-3-3: about 3 inches deep, kept 3 inches clear of the trunk, spread 3 feet out from it. A flat doughnut, never a volcano.
The same clearance applies to plant stems and to house siding, where mulch piled against the wall gives termites a covered route in.
Refreshing rather than replacing
You rarely need to strip old mulch. Rake it to break up any matted crust, check the depth, and top up to 2 to 3 inches total — usually about an inch a year. Adding a fresh 3 inches annually is how beds end up 8 inches deep and suffocating.
Replace fully only when the mulch is compacted into a water-shedding mat, or smells sour and vinegary, which means it has fermented on the pile and can burn plants. Airing it out for a day or two fixes sour mulch. For beds that need feeding rather than covering, compost does a different job and can go underneath.
How this mulch calculator works out its numbers
Volume is area × depth at 27 ft³ per cubic yard, with 5% added by default for uneven spread. Bag counts assume the standard US retail bag of 2 ft³, giving 13.5 bags to the cubic yard.
- Density is 20 lb/ft³, so a cubic yard weighs about 540 lb. Real mulch runs 15 to 30 lb/ft³ depending on type and how wet it is; soaked mulch can weigh half again as much.
- Bag sizes vary. 2 ft³ is standard in the US but 1.5 and 3 ft³ bags exist. Check yours before scaling the counts here.
- Depth guidance follows extension-service practice: 2 to 3 inches for beds, never more than 4. The 3-3-3 rule is a widely used arborist convention rather than a standard.
- Pickup capacity of 2 to 3 cubic yards is for a full-size 6 ft bed and depends on heaping. Mulch is light enough that volume, not payload, is the constraint.
- Prices are US planning ranges gathered September 2026.
Reviewed September 2026.
Figures reviewed . Every worked example on this page is checked against the calculator above.
Mulch Calculator: frequently asked questions
How many bags of mulch in a cubic yard?
13.5 standard 2 cubic foot bags, since a cubic yard is 27 ft³. In practice buy 14. For 4 yards that is 54 bags, which is well past the point where bulk delivery is cheaper.
How far does 1 yard of mulch cover?
162 ft² at 2 inches deep or 108 ft² at 3 inches. At 1 inch it stretches to 324 ft², though that is really only enough for topping up an existing layer.
How deep should mulch be?
2 to 3 inches. That suppresses weeds and holds moisture while still letting air and water through. Beyond about 4 inches mulch starts to suffocate roots and hold water against stems.
How much does a yard of mulch weigh?
About 540 lb, or a quarter of a ton. That is far lighter than soil at 2,430 lb per yard, which is why volume rather than weight limits what your vehicle can carry.
Can you fit 3 yards of mulch in a pickup truck?
Only if you heap it. A standard 6 ft pickup bed holds about 2 cubic yards level with the sides and up to 3 mounded. Four yards needs two trips or a delivery.
What is the 3-3-3 rule for mulch?
Roughly 3 inches deep, kept 3 inches back from the trunk, spread 3 feet out. It prevents the mulch volcano, where mulch piled against a trunk rots the bark and slowly kills the tree.
How much will 20 bags of mulch cover?
About 160 ft² at 3 inches deep, or 240 ft² at 2 inches. Twenty 2 ft³ bags is 40 ft³, which is roughly 1.5 cubic yards.
Should I remove old mulch first?
Usually not. Rake it to break up any matted layer and top up to 2 to 3 inches total, which is about an inch a year. Replace it fully only if it is compacted into a mat or smells sour.