Gravel Calculator

How the gravel calculator works

A 20 × 10-ft area covered 4 inches deep takes 2.59 cubic yards of roadbase gravel — about 4.41 tons. That's 200 sq ft × 0.333 ft = 66.7 cubic feet, or 70 cubic feet with a 5% waste factor, divided by 27; roadbase runs about 1.7 tons per cubic yard. Lighter materials weigh less for the same volume — the same job in pea gravel is 3.63 tons, and in lava rock only 2.33 tons.

The math: we calculate the area (length × width), multiply by the depth, and convert to volume in your unit system. Mass comes from multiplying volume by the gravel type's density — this varies because crushed stone has lots of air, while tightly packed roadbase is heavier per unit volume.

Choosing a gravel type

Density is the reason the same hole needs different tonnages. It also tracks what the material is actually good at: angular crushed material locks together and holds a shape, while rounded stone stays loose and drains fast.

A common mistake is using clean crushed stone where roadbase belongs. Clean stone has no fines, so it never locks up — a driveway built on it stays soft and rutted. Conversely, roadbase in a French drain is a slow failure: the fines wash into the voids and the drain silts shut.

Typical depths by use

• Drainage layer — 2 in / 5 cm; under pavers or behind retaining walls.
• Walkway — 2–3 in / 5–7.5 cm; compacted on a geotextile.
• Patio base — 4–6 in / 10–15 cm; compacted in two lifts.
• Driveway base — 4 in / 10 cm subgrade + 2 in / 5 cm surface dressing = 6 in / 15 cm total.

How far a cubic yard actually goes

One cubic yard is 27 cubic feet, so coverage is simply 27 ÷ your depth in feet. This is the fastest sanity check on any quote:

Order loose volume, then compact in lifts

The calculator gives you loose delivered volume, which is what you buy. Compacted gravel occupies roughly 15–20% less space than the same material loose, so a 4-inch finished layer starts as closer to 5 inches of dumped material. That shrinkage is already covered for ordering purposes — do not add it a second time on top of the waste factor.

Spread and compact in lifts of 3–4 inches rather than one deep pour. A plate compactor only densifies the top few inches; dump 8 inches at once and the bottom half stays loose, which is exactly how driveways develop ruts a year later. Lightly wetting roadbase before compacting helps the fines pack.

The subgrade matters more than the gravel

Gravel spreads load; it does not create bearing capacity. If the soil underneath is soft, wet, or organic, the stone will migrate into it and the surface will sink no matter how much you ordered. Strip sod and topsoil down to firm subsoil first, and lay a woven geotextile between soil and stone on anything soft. The fabric keeps the two layers from mixing, which is usually the difference between a base that lasts a decade and one that needs re-topping every other year.

Worked example: a 12 × 50-ft driveway

600 sq ft at 6 in total depth = 300 cubic feet. Add 5% waste and divide by 27: 11.67 cubic yards. In roadbase at 1.7 tons/cu yd that is 19.8 tons — about two tandem-axle truckloads.

Built properly it is two orders: 4 inches of roadbase (7.78 cu yd, 13.2 tons) compacted as the structural layer, then 2 inches of clean crushed stone as the driving surface (3.89 cu yd, 5.8 tons). Ordering all 19.8 tons as one material is the single most common driveway ordering error.

Worked example: a 20-ft French drain

A trench 12 in wide and 12 in deep of stone over 20 ft is 20 cubic feet — with waste, 0.78 cu yd, or about 1.1 tons of clean crushed stone. Note this lands under the typical 1 cu yd delivery minimum, so you will either pay for a full yard or haul it yourself. Use washed, angular stone and wrap the trench in filter fabric.

Tons or cubic yards?

Suppliers quote both and the two are not interchangeable without the density. Quarries and anyone running a scale usually sell by the ton, because that is what the truck weighs in at. Landscape yards more often sell by the cubic yard, because that is what the loader bucket measures. Always convert before comparing two quotes — at 1.7 tons/cu yd, $40/ton and $60/cu yd are not remotely the same price ($68/cu yd vs $60/cu yd). Toggle the output unit above to get whichever one your supplier speaks.

Why the waste factor is smaller (5%)

Gravel is dumped and spread, not cut. The main loss is over-spill at edges and slight compaction-driven settling. Raise it to 10% if the area has irregular edges, a slope that will let material creep, or no border restraint to hold the stone in place.

Delivery vs pick-up

Most suppliers have a minimum order for delivery (typically 1 cu yd / ~0.8 m³ and a $50–$100 fee). Under that, hauling it yourself is usually cheaper — but check the weight before you load. One cubic yard of crushed stone weighs about 3,000 lb (1.4 tonnes), which overloads most half-ton pickups. A half-ton's payload is typically 1,500–2,000 lb, so roughly half a cubic yard is a safe trip; a ¾-ton truck handles about one yard. Check the door-jamb payload sticker rather than trusting the "half-ton" name, which is historic rather than literal.

For anything over about 3 cubic yards, delivery almost always wins on both cost and time — a tandem-axle dump truck carries 10–14 cubic yards in one drop. Ask the driver to dump on plywood or a tarp if the pile lands on a finished surface.

What gravel costs

Prices vary sharply by region and by how far you are from a quarry, since hauling dominates the cost of a low-value bulk material. As a 2026 planning range in the US, expect roughly $20–$45 per ton for crushed stone and roadbase, $30–$55 for pea gravel, $40–$70 for decomposed granite, and $60–$120 for decorative river rock, plus a delivery fee. Enter your local quoted price in the Advanced options above and the calculator will total the job for you. Always confirm with a local supplier before budgeting.

Frequently asked questions