Guide
Volume vs Weight: The Trap in Soil, Gravel and Concrete
Published July 19, 2026
A cubic yard of mulch and a cubic yard of gravel are the same volume and wildly different weights — mulch is mostly air and organic fiber, gravel is mostly mineral, and the difference between them is more than a ton per cubic yard. That gap is exactly why one is priced and delivered by the yard and the other is priced and delivered by the ton, and knowing which convention applies to your material is worth understanding before a delivery truck shows up with a number that doesn't match what you expected.
The same volume-versus-weight confusion shows up a second time with soil specifically, because the same shovelful of dirt has three genuinely different volumes depending on whether it's sitting undisturbed in the ground, freshly dug into a loose pile, or compacted back down — and none of those three volumes is the wrong one, they're just answering different questions.
A cubic yard is not a cubic yard
- Mulch (bark or wood chip) — commonly in the range of 400-800 lb per cubic yard, light enough that a pickup truck can genuinely run out of box space before it comes close to its weight limit.
- Topsoil — commonly cited around 2,000-2,200 lb per cubic yard, close to a literal ton per yard as a rough rule of thumb, though moisture content moves this figure noticeably.
- Sand — commonly in the range of 2,600-3,000 lb per cubic yard, among the heavier common landscaping materials by volume.
- Gravel and crushed stone — commonly in the range of 2,600-2,900 lb per cubic yard, roughly 1.3 to 1.5 tons, varying with stone size and how tightly it settles in the pile.
- Concrete, mixed and wet — commonly cited around 4,000-4,100 lb per cubic yard, close to 150 lb per cubic foot, which is the figure the concrete slab calculator and concrete post calculator work from when converting a volume of concrete to a truck load or a bag count.
These are working ranges, not lab-grade constants — moisture content alone can shift topsoil's weight by several hundred pounds per yard between a dry stockpile and one that's been rained on, which is worth knowing before assuming a delivery invoice's tonnage tells you exactly how many cubic yards actually arrived.
Why heavy material is priced by the ton and light material by the yard
A delivery truck has two limits working against each other: how much volume its bed physically holds, and how much weight it's legally allowed to carry. For a light material like mulch, the truck runs out of box space long before it gets anywhere near its weight limit, so pricing and quoting by volume makes sense — the yard is genuinely the scarce resource on that load. For a heavy material like gravel or sand, the opposite is true: the truck hits its legal weight limit with plenty of box space still empty, so pricing and quoting by the ton reflects what's actually constraining the delivery.
This is also why a 'small load' of gravel can still require a specific minimum tonnage that feels large for the job — the yard isn't sizing the minimum around your project, it's sizing it around what makes a delivery run worth dispatching a weight-limited truck for.
Bank, loose and compacted: three volumes of the same soil
Bank measure is the soil's volume undisturbed in the ground, before anything touches it — this is what a survey or an excavation plan describes. Loose measure is the same soil's volume once it's been dug, because excavation breaks the soil apart and introduces air pockets between particles that weren't there in the compacted, undisturbed ground — the pile of dirt next to a hole is reliably bigger than the hole it came out of. Compacted measure is the soil's volume after it's placed and mechanically compacted back down, which for many soils lands close to, and sometimes below, the original bank volume, because compaction equipment can pack particles tighter than the soil's natural undisturbed state.
The swell-and-shrink range, and why it's a range
Excavated soil commonly swells somewhere in the range of 15 to 30% from bank to loose measure, with the actual figure depending heavily on soil type — a dense clay tends toward the higher end of that range because its particles interlock tightly in their undisturbed state, while a loose sand that was already close to its loose density in the ground swells less. There isn't one universal swell factor this site can print with confidence, because the honest answer genuinely depends on the specific soil, which is exactly the kind of figure worth treating as a starting estimate rather than a fixed constant.
This is why the excavation spoil calculator and dumpster size calculator both ask for a swell allowance as an adjustable input rather than baking in one number: a spoil pile or a debris container sized only from bank-measure volume will consistently be too small for what the excavation actually produces.
What this means for your order
For fill and backfill work, order by the volume the finished, compacted job actually needs, then plan on the delivered or excavated volume being larger than that figure by the swell allowance until it's been placed and compacted. For bulk delivery of dense material — sand, gravel, soil — expect the yard to quote and bill by weight even though your own planning is in cubic yards, and use the density figures above, or the specific yard's own stated density if they publish one, to convert between the two rather than assuming a flat one-ton-per-yard rule applies to every material.
The bulk delivery calculator runs this conversion directly, taking a volume and a material's density to estimate the weight a delivery will actually invoice, which is worth checking before an order rather than after a surprising delivery ticket.
FAQ
If I dig a hole and want to refill it later, do I need the same volume of soil I removed?
Less, generally, once it's compacted back down — the loose pile from digging the hole is bigger than the hole itself due to swell, but compacted backfill typically settles close to or slightly below the original bank volume, so stockpiling every bit of loose spoil for later backfill usually leaves a genuine surplus.
Why did my gravel delivery weigh less than I calculated?
Most often because the density figure used in the calculation was for a different stone type or gradation than what was actually delivered — density varies meaningfully between an open-graded drainage stone and a dense-graded base material, so check the specific product's stated density rather than a general gravel figure when the math needs to be precise.
Does moisture content change how much a cubic yard of soil or mulch weighs?
Yes, significantly for both — wet topsoil can weigh considerably more per cubic yard than dry topsoil, and rain-soaked mulch is heavier than the same pile after a dry week. This matters most when a delivery is billed by weight, since a wet load can cost more for the identical volume of material.
Is compacted volume always less than bank volume?
Not always — it depends on the soil and the compaction effort. Some soils compact to slightly less than their original bank volume, but a poorly compacted fill, or one that was never adequately compacted, can settle further over time after the job is finished, which is a separate risk from the swell-and-shrink math covered here.
Should I use a swell factor for gravel and sand the way I would for excavated soil?
Not in the same sense — gravel and sand are sold and delivered already loose, so there's no bank-to-loose swell step to account for the way there is with excavated native soil. The volume-to-weight conversion above is the one that matters for those materials, not a swell factor.