Mulch Calculator
You need 5.5 yd³ of Shredded bark mulch, or 69 bags.
| Figure | Exact | With 10% waste |
|---|---|---|
| Volume | 4.63 yd³ | 5.09 yd³ |
| Same volume, small units | 125 ft³ | 138 ft³ |
| Bags at 2 ft³ (standard bag) | 63 | 69 |
| Weight | 2,315 lb | 2,546 lb (≈ 3 pickup loads) |
Calculated at 500 lb per cubic yard for shredded bark mulch. Mulch weight swings a long way with moisture — a soaked load can be half again heavier than the dry figure, which matters if you are hauling it yourself. Pickup loads assume about 1,200 lb of usable payload, so check your own door-jamb sticker before loading. Bulk volume rounds up to the next half yd³, since most yards deliver in half-yard increments; bag counts round up to whole bags. Delivery fees are not included.
Enter your bed size and depth to find how much mulch, compost, or topsoil you need — in cubic yards, bags, and delivered weight, with bulk and bagged prices compared.
How to use this calculator
- Pick imperial or metric, then the bed shape. For an irregular bed, break it into rectangles and circles and add the results.
- Enter the dimensions and depth. Depth is the finished mulch layer — if you already have two inches down and want three, enter 1, not 3.
- Choose the material. This sets the weight per yard and updates the typical-depth hint, which changes a lot between bark mulch and topsoil.
- Set the bag size you can actually buy locally — 2 ft³ is the US standard, but 1.5 and 3 ft³ are common too.
- Enter both a bulk price per yard and a price per bag to see which way is cheaper for your job. This is the number most people guess at and get wrong.
The formula
Cubic feet = Area (ft²) × (Depth (in) ÷ 12) · Cubic yards = Cubic feet ÷ 27 · Bags = Cubic feet ÷ Bag size (ft³)
Order volume = Cubic yards × (1 + waste ÷ 100), rounded up to the next half yard · Weight = Cubic yards × Density (lb/yd³)
Worked example — a 25 × 20 ft bed
You are laying 3 inches of shredded bark mulch over a 25 ft × 20 ft bed, at the standard 10% waste factor.
- Area: 25 × 20 = 500 ft²
- Convert depth: 3 ÷ 12 = 0.25 ft
- Cubic feet: 500 × 0.25 = 125 ft³
- Cubic yards: 125 ÷ 27 = 4.63 yd³
- With 10% waste: 4.63 × 1.10 = 5.09 yd³ — order 5.5 yd³
- Or in bags: 137.5 ft³ ÷ 2 = 69 bags
- Weight: 5.09 × 500 = ≈ 2,550 lb — three pickup trips, not one
At $40 per yard delivered, the bulk order is about $220. At $4.50 a bag, the same job is $311 — and 69 bags to load, haul, open, and dispose of. This is the crossover that makes bulk worth the delivery fee.
Bulk or bagged?
The honest answer depends almost entirely on how much you need. Bagged mulch typically costs two to three times more per cubic yard than bulk, but bulk carries a delivery charge — often $50 to $100 — that has to be spread over the load. That gives three rough zones:
| How much you need | Usually cheaper | Why |
|---|---|---|
| Under ½ yd³ (≈ 7 bags) | Bags | Delivery fee dwarfs the material cost |
| ½ – 2 yd³ (7–27 bags) | Roughly even | Depends on the delivery fee and your local bag price |
| Over 2 yd³ (27+ bags) | Bulk, clearly | Material savings outrun the delivery charge |
Bags still win on things money does not measure: you can buy them in stages, store the leftovers dry, and carry them through a gate a truck cannot reach. Bulk wins on price, on not having 69 plastic bags to dispose of, and on colour consistency — one load is one batch.
Depth, and the mulch volcano
Two to three inches is the working range for almost every bed. Three inches suppresses weeds effectively while still letting water and air reach the soil. Below two inches, weeds come straight through and the mulch dries out and blows around.
Going deeper is the mistake, and it is a costly one twice over — you buy material you did not need, and you can damage the plants. Mulch piled four to six inches deep stays waterlogged, and roots grow up into the mulch layer instead of down into the soil. Piling it in a cone against a trunk, the so-called mulch volcano, traps moisture against the bark, invites rot and rodents, and can kill an established tree over a few years. Keep mulch pulled back a few inches from trunks and stems, and think of it as a flat blanket, not a mound.
Topping up an existing bed
Organic mulch breaks down, so beds need refreshing roughly once a year — but almost never a full depth's worth. Push a finger down to the soil in a few places and measure what is actually left. If two inches remain and you want three, you are buying one inch: a third of the material, and a third of the cost. Enter the difference in the depth field, not your target depth.
Rake and fluff what is already there before adding more. Old mulch often looks thinner than it is because it has compacted, and breaking up a matted layer improves water penetration more than another inch on top would.
Common mistakes to avoid
- Entering your target depth when topping up. The calculator needs the layer you are adding, not the finished total. This is the single most common way people over-order.
- Ignoring weight when hauling it yourself. A cubic yard of bark mulch is about 500 lb and fine in any pickup. A cubic yard of topsoil is about 2,000 lb and over the payload rating of most half-ton trucks on its own. Check your door-jamb sticker.
- Assuming mulch and topsoil estimate the same. Same units, very different depths and weights. Topsoil goes 4–6 inches deep and weighs four times as much per yard.
- Forgetting the delivery fee in a bulk comparison. This calculator prices material only. Add your supplier's delivery charge to the bulk figure before deciding.
- Buying wet. Bulk mulch is sold by volume, so moisture does not cost you extra — but it does make the load far heavier than the weight shown here, which is a dry figure.
How we calculate this
Volume is area × depth: length × width for a rectangle, π × (diameter ÷ 2)² for a circle. Depth converts from inches to feet before multiplying, and the total divides by 27 for cubic yards. The waste factor is applied to the volume, so it flows through to bags, weight, and cost together. Bag counts round up to whole bags; bulk rounds up to the next half yard, which is the increment most yards deliver in. Weight uses published dry bulk densities — 500 lb/yd³ for bark mulch and wood chips, 1,100 for compost, 1,600 for garden soil mix, 2,000 for screened topsoil. Pickup-load estimates assume about 1,200 lb of usable payload. All arithmetic runs in metric internally and converts once for display, so the unit toggle does not drift.
Sources
Frequently asked questions
How much mulch do I need for a 500 square foot bed?
At the usual 3-inch depth, 500 square feet needs 125 cubic feet of mulch, which is 4.63 cubic yards. Add the standard 10% waste factor and you are ordering about 5.1 cubic yards, or 69 of the standard 2-cubic-foot bags. That is the point where bulk delivery almost always beats bagging it.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it takes 13.5 of the standard 2-cubic-foot bags, 18 of the 1.5-cubic-foot bags, or 9 of the 3-cubic-foot bags. Suppliers usually price a yard of bulk mulch at roughly the cost of 8 to 10 bags, which is why bulk gets cheaper the moment you need more than about half a yard.
How deep should mulch be?
Two to three inches for most beds. Three inches suppresses weeds well while still letting water and air through. Going deeper is a common and expensive mistake — mulch piled 4 to 6 inches deep holds too much moisture against roots, and piling it against a trunk (a "mulch volcano") rots the bark and eventually kills the tree. Keep mulch a few inches clear of trunks and stems.
Is bulk mulch cheaper than bagged?
Almost always, once you need more than about 2 cubic yards. Bagged mulch typically costs two to three times more per cubic yard than bulk, but bulk carries a delivery fee that has to be spread across the load. Below roughly half a yard, bags win on convenience and cost; above 2 yards, bulk wins clearly. This calculator prices both so you can see where your job lands — enter a price in each field.
How much does a yard of mulch weigh?
Dry bark mulch runs about 500 pounds per cubic yard, wood chips similar, and compost closer to 1,100. Screened topsoil is far heavier at roughly 2,000 pounds per yard. Water changes this a lot: a soaked load can weigh half again as much as the dry figure. That matters if you are hauling it yourself — a half-ton pickup is generally rated for around 1,000 to 1,500 pounds of payload, so one yard of wet topsoil can be over the limit on its own.
Will a yard of mulch fit in my pickup truck?
By volume, most full-size pickup beds hold about 2 to 2.5 cubic yards level with the rails, so a yard of mulch physically fits easily. Weight is the real limit, not space. One yard of bark mulch at roughly 500 pounds is fine for any half-ton truck. One yard of topsoil at roughly 2,000 pounds is not — check the payload rating on your door-jamb sticker, and split heavy material across two trips.
How often should mulch be replaced?
Organic mulch breaks down and needs topping up roughly once a year, though you rarely need a full depth's worth. Measure what is left, subtract it from your target depth, and enter only the difference here. If two inches remain of a three-inch target, you are buying one inch, which is a third of the material — a distinction that saves real money on a big bed.
What is the difference between mulch and topsoil?
Mulch goes on top of the soil as a protective layer: it suppresses weeds, holds moisture, and moderates soil temperature. Topsoil goes into the ground to build growing medium. They are ordered the same way, by the cubic yard, but the depths and the weights are very different — topsoil is about four times heavier per yard and is usually placed 4 to 6 inches deep rather than 2 to 3.