Mulch, Topsoil & Gravel Calculator
Yards, tons and bags for any bulk landscape material — plus why a ton of mulch is four times a ton of stone, and when bags beat delivery.
What a ton actually buys, by material
Coverage at each depth
324 divided by the depth in inches. One division, done in the aisle.
A ton means four times as much mulch as stone
Crushed stone runs about 2,700 lb to the cubic yard, so a ton of it is 0.74 yards. Shredded mulch runs about 700, so a ton of that is 2.86 yards. The same word, the same order form, and nearly four times as much material for one as the other. Screened topsoil sits at almost exactly 2,000 lb a yard, which makes a ton and a yard the same thing — a genuine coincidence, and a misleading one, because it's the material most people learn on and it teaches them the words are interchangeable.
One cubic yard covers 324 square feet one inch deep. That's the only number worth memorising here: 27 cubic feet divided by a twelfth of a foot. Square feet per cubic yard is 324 ÷ depth in inches — 162 at two inches, 108 at three, 81 at four.
Compaction runs six to one between angular and rounded stone. Crusher run interlocks and loses about a quarter of its volume under a compactor, so you order a third more than the finished depth. Pea gravel is rounded and already close to its densest packing, so it loses about a twentieth. Using one allowance for both leaves you short on the drive and with a heap left over in the bed.
Bags aren't always the expensive option. Delivery is a flat fee, so on small jobs it outweighs the per-yard saving. At typical prices — $4.50 for a 2 cu ft bag against $40 a yard plus $75 delivery — the crossover is around 3.6 cubic yards, which at three inches deep is about 390 square feet. Below that, bags genuinely win.
- Never pile mulch against a trunk. The mulch volcano keeps bark permanently damp, which rots it and invites borers, and it encourages roots to grow up into the mulch where they circle and girdle the tree. It kills slowly enough that nobody connects the two.
- Deeper mulch doesn't suppress more weeds. Past about four inches it starts suffocating roots, and a deep layer intercepts light rain entirely before any reaches the soil.
- Order the finished depth, not the loose volume. The depth you want is what's left after it settles, which is why every material here carries its own allowance.
- Measure the bed, not the garden. Most people overestimate an irregular bed by a third, and it isn't returnable once it's tipped on the drive. If you're between sizes, take the smaller.
- Check what the truck can reach. A few yards of stone is several tons — well past what a half-ton pickup should carry, and enough to mark a soft drive. Ask for it on a tarp.
How to use
- Pick the material — density and compaction both depend on it.
- Enter the bed dimensions and the depth you want when it has settled.
- Order the compacted figure, not the finished one.
- Compare bags against bulk with your own delivery fee before buying.
Frequently asked questions
How many square feet does a cubic yard cover?
Three hundred and twenty-four at one inch deep, and 324 divided by the depth in inches at anything else — 162 at two inches, 108 at three, 81 at four. The number comes straight out of the units: 27 cubic feet divided by a twelfth of a foot. It is worth memorising, because it turns every job of this kind into one division you can do in the aisle.
Is a ton of mulch the same as a cubic yard?
Nowhere near. Shredded mulch runs about 700 pounds to the cubic yard, so a ton of it is nearly three yards. Crushed stone runs about 2,700, so a ton of that is three quarters of a yard. The same word means close to four times as much material for one as the other, which is why mulch is sold by volume and stone by weight.
Why do people confuse tons and yards for landscape materials?
Largely because of topsoil. Screened topsoil happens to weigh almost exactly 2,000 pounds a cubic yard, so for that one material a ton and a yard genuinely are the same thing. It is a coincidence of density, but it is also the material most people meet first, and it quietly teaches them the two words are interchangeable everywhere.
How much extra should I order for compaction?
It depends entirely on the material, by as much as six to one. Crusher run loses about a quarter of its volume under a compactor, so you order a third more than the finished depth. Rounded pea gravel loses about a twentieth. The depth you specify is the finished depth, so the allowance is not optional — but using one figure for every material is how you end up short on the drive and with a heap left in the bed.
Why does crushed stone compact more than pea gravel?
Because the pieces are angular and they interlock. Crusher run also carries its own fines, which migrate into the gaps between the larger pieces and lock the whole thing into a hard surface — that is what makes it a base material. Pea gravel is rounded and already close to its densest packing, so there is very little left to compress, and for the same reason it never locks together and rolls underfoot forever.
Are bags or bulk cheaper for mulch?
Bags win on small jobs, which surprises most people. Delivery is usually a flat fee, so it does not scale down. At typical prices — around $4.50 for a two cubic foot bag against $40 a yard plus $75 delivery — the crossover falls near three and a half cubic yards, which at three inches deep is roughly 390 square feet. Below that, bags genuinely cost less.
How deep should mulch be?
Two to three inches, and never more than four. Beyond that it stops suppressing any additional weeds and starts working against the plants: roots need gas exchange, and a thick layer restricts it. A deep layer also intercepts light rain entirely, so the soil beneath it can be dry after a shower that should have watered it.
Why should mulch not touch a tree trunk?
Because bark is not root tissue and it is not built to stay wet. A cone of mulch piled against the trunk keeps it permanently damp, which rots it and invites boring insects, and it encourages roots to grow upward into the mulch where they circle and eventually girdle the tree. It works slowly enough that the tree dies years later and nobody connects the two. Pull mulch back so the flare at the base is visible.
How deep should topsoil be for a new lawn?
Four to six inches of screened topsoil is the usual target, and less than four is where problems start — roots reach whatever is underneath, which on a new build is often compacted subsoil, and the lawn then behaves as though it is growing in a shallow container. On the area of a whole lawn that is a great many yards, so it is worth measuring carefully before ordering.
How much does a cubic yard of gravel weigh?
Around 2,600 to 3,000 pounds depending on the type, so between about one and a third and one and a half tons. That matters twice over: it is well past what a half-ton pickup should carry, so a few yards is a delivery rather than a trip, and a loaded truck tipping several tons onto a soft or decorative drive will leave a mark. Asking for it on a tarp is a reasonable request.
How do I calculate material for an irregular bed?
Break it into rectangles and circles, work each one out and add them together. The commonest error is not the arithmetic but the estimate — people overestimate an irregular bed by about a third, and bulk material is not returnable once it is on the drive. If you land between two order sizes, take the smaller one: a second small bag order costs less than a spare yard rotting in a heap.
What is the difference between crusher run and #57 stone?
Fines. Crusher run is stone plus the dust from crushing it, so the small particles fill the voids between the large ones and the whole thing compacts into a hard, largely impermeable surface — a base material. Number 57 is open-graded, all similar-sized pieces with the fines screened out, so it drains freely and stays loose. One is for building on, the other for water to move through.
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