Area 1
Advanced options
Sets the tons-per-yard conversion.
Your depth is the finished depth after compacting.
Spillage and uneven subgrade.
Most suppliers sell gravel by weight.
This gravel calculator works out how much gravel you need in both cubic yards and tons — and it accounts for compaction, which is the step that leaves most driveways an inch short. Covers ten stone types, four shapes, and stacked layers for a full driveway build.
The short answer
Gravel volume is length × width × depth ÷ 27, all in feet. A 40 × 12 ft driveway at 4 inches is 40 × 12 × 0.333 ÷ 27 = 5.9 cubic yards.
Then convert to tons — most suppliers sell by weight. At roughly 2,700 lb per cubic yard, that’s about 8 tons. Add 20% if the gravel will be compacted, because that 4 inches is the finished depth, not the delivered depth.
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How to use this gravel calculator
Enter your area and the depth you want after compaction, and the gravel calculator returns both cubic yards and tons, plus truck loads and cost. Four shapes are covered:
- Rectangle — driveways, parking pads, paths, patio bases
- Circle — fire pit surrounds, tree rings, round beds
- Triangle — corner sections and wedge-shaped areas
- Trench — French drains, footing drains, pipe bedding
Building a driveway in layers? Use Add another area or layer and enter each layer separately with its own depth — base, middle and surface. The calculator totals them, so you get one delivery figure instead of doing three sums.
Under Advanced options you set the stone type, which changes the tons-per-yard conversion, and the compaction allowance. That second setting is the one that matters most, and it’s covered next.
The gravel calculator formula
Cubic yards = Length (ft) × Width (ft) × Depth (ft) ÷ 27
Tons = Cubic yards × (lb per yd³ ÷ 2,000)
Depth in feet = inches ÷ 12
2 in = 0.167 ft · 3 in = 0.25 ft · 4 in = 0.333 ft · 6 in = 0.5 ft
Worked example — 40 × 12 ft driveway, 4 in of #57 stone
Skipping the compaction step would have you ordering 6.2 yards instead of 7.5 — and finishing about two thirds of an inch shallow, at 3.3 inches instead of 4.
The compaction allowance most calculators skip
This is the single biggest reason people come up short on gravel. When you spread loose gravel and run a plate compactor over it, the stones lock together and the fines fill the voids. The layer loses 15–25% of its depth, and 20% is a reasonable default for a driveway.
So if you want 4 inches of finished, compacted gravel, you need to deliver and spread about 5 inches loose. Order for the finished depth alone and your driveway ends up around 3¼ inches — thin enough to rut under a car within a season.
| Situation | Allowance | Why |
|---|---|---|
| Decorative stone, not compacted | 0% | Stays as loose as delivered |
| Drainage fill in a trench | 0–10% | Clean stone has little to settle into |
| Path or patio base, hand tamped | 15% | Partial compaction |
| Driveway, plate compactor | 20% | Standard residential practice |
| Crusher run under a roller | 25% | Fines migrate and lock tight |
A plate compactor only densifies the top few inches. Spreading 8 inches and compacting once leaves the bottom half loose, which is exactly where you need density. Place in lifts of no more than 4 inches and compact each before adding the next.
Converting cubic yards to tons
Most aggregate suppliers sell gravel by the ton because it’s weighed on a certified scale. You measure in cubic yards. The conversion depends entirely on the stone.
| Material | lb per yd³ | Tons per yd³ | yd³ per ton |
|---|---|---|---|
| Lava rock | 1,200 | 0.60 | 1.67 |
| #57 stone | 2,700 | 1.35 | 0.74 |
| Crushed limestone | 2,700 | 1.35 | 0.74 |
| Marble chips | 2,700 | 1.35 | 0.74 |
| #67 / #8 stone | 2,800 | 1.40 | 0.71 |
| Pea gravel | 2,900 | 1.45 | 0.69 |
| Decomposed granite | 2,900 | 1.45 | 0.69 |
| River rock | 3,000 | 1.50 | 0.67 |
| Crusher run / 21A | 3,000 | 1.50 | 0.67 |
These are mid-range figures for dry, loose material. Moisture adds weight without adding volume, so a rained-on load weighs more for the same coverage — which matters if you’re buying by the ton. Source rock matters too: granite and trap rock run heavier than limestone.
How much area does gravel cover?
| Depth | Per cubic yard | Per ton (#57) | Typical use |
|---|---|---|---|
| 1 inch | 324 ft² | 240 ft² | Topping up an existing surface |
| 2 inches | 162 ft² | 120 ft² | Decorative beds, light paths |
| 3 inches | 108 ft² | 80 ft² | Walkways, surface layer |
| 4 inches | 81 ft² | 60 ft² | Driveway layer, paver base |
| 6 inches | 54 ft² | 40 ft² | Driveway base, heavy use |
| 12 inches | 27 ft² | 20 ft² | Trench and drain fill |
Per-ton figures are for #57 stone at 2,700 lb per cubic yard. Heavier stone covers less ground per ton — a ton of crusher run covers about 10% less than a ton of #57 at the same depth, because you’re getting fewer cubic yards for the same weight.
Gravel types and what each is for
| Type | Nominal size | Best for | Watch out for |
|---|---|---|---|
| Crusher run also 21A, QP, road base |
¾ in down to dust | Base layers, compacted parking areas | Fines slow vertical drainage |
| #3 stone | ~1½–2 in | Sub-base on soft ground | Too coarse to walk or drive on |
| #57 stone | ~¾–1 in | Driveways, drainage, paver base | Won’t bind without fines |
| #67 / #8 stone | ~⅜–¾ in | Surface layer, walkways | Migrates on slopes |
| Pea gravel | ⅜ in, rounded | Playgrounds, decorative, patios | Rounded stones roll and spread |
| River rock | 1–3 in, rounded | Dry creek beds, decorative | Poor underfoot, won’t compact |
| Decomposed granite | ¼ in and fines | Paths, natural-look surfaces | Tracks indoors, erodes in rain |
| Marble chips | ½–1 in | Decorative beds | Yellows over time, reflects heat |
| Lava rock | ½–2 in | Lightweight decorative mulch | Sharp edges, blows around |
Crushed stone has fractured faces that interlock under load. Rounded stone — pea gravel, river rock — behaves more like ball bearings: it shifts under tires, migrates to the edges, and never really locks up. Use rounded stone where it’s decorative or underfoot, and angular crushed stone anywhere a vehicle goes.
What the numbers actually mean
Worth clearing up, because plenty of sources get this wrong: #57 does not mean 57 of anything, and it isn’t a measurement in inches. The numbers come from standard gradation specifications — AASHTO M 43 and the parallel ASTM D448 — which define a sieve envelope rather than a single size.
A #57 spec means the material passes a 1½ inch sieve, is mostly retained on a #4 sieve, and has a defined distribution in between. In practice that’s roughly ¾ to 1 inch stone with minimal fines. Lower numbers are generally coarser (#3 is bigger than #57, which is bigger than #8), but the numbering isn’t a linear size scale, so you can’t calculate one size from another.
The practical takeaway: order by the number your local quarry uses, and ask what the nominal size is if you’re unsure. Regional names vary a lot — crusher run is called 21A in Virginia, QP in some markets, and road base or base course elsewhere, and they’re broadly the same product.
How deep should a gravel driveway be?
Published guidance varies more than you’d expect, so here’s the honest range with context rather than one number.
| Situation | Total depth | Structure |
|---|---|---|
| Topping an existing driveway | 1–2 in | One surface layer of #57 or #67 |
| Light-use path or walkway | 3–4 in | Base plus thin surface |
| Standard residential driveway | 8–12 in | Three layers, each compacted |
| Soft or clay subgrade | 12–18 in | Deeper sub-base, consider geotextile |
| Rural road, truck traffic | 12–18 in | Heavy base course plus surface |
The three-layer structure for a new residential driveway on native soil:
- Sub-base, 4–6 inches. Large angular stone — #3 or comparable base course. Carries the load and spans soft spots. Compact before the next layer.
- Middle, 2–4 inches. #57 stone or crusher run. Bridges the gap between coarse base and fine surface, stopping the top layer washing down into the voids.
- Surface, 1–2 inches. #57, #67 or #8. This is what you see and drive on. Angular for grip, fine enough to ride smoothly.
Two details that decide whether it lasts. Crown the surface — about a 2 inch rise at the center across a 12 ft width — so water sheds sideways rather than pooling in the wheel tracks. And lay geotextile fabric over soft or clay subgrade before the sub-base; it stops stone punching down into mud, and it’s cheap compared to re-doing the driveway.
What does gravel cost?
| Item | Typical US price |
|---|---|
| Crusher run, per ton | $20–$40 |
| #57 crushed stone, per ton | $30–$60 |
| Pea gravel, per ton | $40–$80 |
| River rock, per ton | $60–$150 |
| Delivery, per load | $50–$150 |
| Geotextile fabric, per ft² | $0.20–$0.50 |
| Plate compactor rental, per day | $60–$100 |
Haul distance drives price more than anything else — gravel is cheap material and expensive freight. Picking it up yourself saves the delivery fee but rarely pays: a half-ton pickup can only legally carry about half a cubic yard of stone, so ten yards is twenty trips.
Gravel ordering mistakes to avoid
- Ignoring compaction. Order for finished depth only and you’ll be 15–25% short.
- Mixing up yards and tons. They aren’t interchangeable, and the factor differs by stone type.
- Using rounded stone on a driveway. Pea gravel and river rock migrate under tires.
- One thick layer instead of lifts. A compactor only densifies the top few inches.
- Skipping fabric on clay. Stone sinks into soft subgrade and the driveway pumps mud.
- No crown. Flat gravel holds water, which is what creates potholes.
- Filling a pickup by volume. Payload runs out at about half a yard of stone.
Frequently asked questions
How do I calculate how much gravel I need?
Multiply length by width by depth, all in feet, then divide by 27 for cubic yards. Multiply by the stone’s tons-per-yard figure — about 1.35 for #57 — to get tons. Add 15–25% if the gravel will be compacted, since your target depth is the finished depth.
How many tons of gravel are in a cubic yard?
About 1.35 tons for #57 stone or crushed limestone, 1.45 for pea gravel, and 1.5 for crusher run or river rock. Lava rock is much lighter at 0.6 tons per cubic yard. Divide the material’s pounds per cubic yard by 2,000.
How much area does a ton of gravel cover?
A ton of #57 stone is about 0.74 cubic yards, which covers roughly 240 ft² at 1 inch deep, 120 ft² at 2 inches, 80 ft² at 3 inches and 60 ft² at 4 inches. Heavier stone covers slightly less per ton.
How deep should a gravel driveway be?
A new residential driveway on native soil typically needs 8–12 inches total in three compacted layers: 4–6 inches of coarse sub-base, 2–4 inches of middle layer, and 1–2 inches of surface stone. Soft clay subgrade or truck traffic pushes that to 12–18 inches. Topping an existing driveway needs only 1–2 inches.
What does #57 gravel mean?
It’s a gradation specification under AASHTO M 43 and ASTM D448, not a size in inches. A #57 spec passes a 1½ inch sieve and is mostly retained on a #4 sieve, which works out to roughly ¾ to 1 inch stone with very few fines. Lower numbers are generally coarser, but the numbering isn’t a linear size scale.
What is the best gravel for a driveway?
Crusher run for the base because its fines help it compact and bind, and #57 or #67 crushed stone for the surface because the angular faces interlock. Avoid rounded stone like pea gravel or river rock on anything you drive on — it shifts under tires and migrates to the edges.
How much does a yard of gravel weigh?
Around 2,700 lb for #57 stone, 2,900 for pea gravel and 3,000 for crusher run or river rock. Lava rock is far lighter at about 1,200 lb. Wet material weighs more without covering any more ground.
How much gravel does a dump truck hold?
A single-axle dump truck carries roughly 5–8 cubic yards and a tandem-axle 10–14, but weight limits usually cap the load before the box fills. For crushed stone, a tandem typically hauls about 10 yards. A half-ton pickup can only legally carry about half a cubic yard.
Do I need landscape fabric under gravel?
Under a driveway on clay or soft ground, yes — woven geotextile stops stone punching down into the subgrade and mud pumping up. For decorative beds, thin weed fabric is optional and often fails within a few years as debris builds up on top and weeds root in it.
How much extra gravel should I order?
Add 15–25% for compaction if the gravel is being compacted, plus about 5% for spillage and uneven subgrade. Those are separate allowances doing different jobs. Delivery fees mean a second small load costs far more than ordering slightly over.
Should gravel be compacted?
For driveways, paths and paver bases, yes — uncompacted gravel ruts and migrates. Compact in lifts no deeper than 4 inches, because a plate compactor only densifies the top few inches. Clean drainage stone in a trench needs no compaction, and decorative stone is left loose.
Can I use this gravel calculator in metric?
Yes. Switch the header toggle to m / mm and enter dimensions in metres and millimetres. Results show cubic yards, cubic metres, US tons and metric tonnes together, so you can order in whatever unit your supplier quotes.
Standards and sources
- AASHTO M 43 — Standard sizes of coarse aggregate for highway construction
- ASTM D448 — Standard classification for sizes of aggregate for road and bridge construction
- Material weights compiled from multiple aggregate supplier references and reported as mid-range values; source rock and moisture cause real variation
- Driveway layer depths reflect the range across published contractor and supplier guidance rather than a single source
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How this gravel calculator works out its numbers
Volume uses standard geometric formulas with all inputs normalised to feet, then divided by 27 for cubic yards. The depth you enter is treated as the finished depth: the compaction allowance is added on top to give the loose volume you actually need delivered, and the waste allowance is applied after that. Weight uses mid-range pounds-per-cubic-yard figures for each stone type, converted at 2,000 lb per US ton. Truck loads apply both a volume limit and a payload limit and report whichever is reached first.
Stone weights vary with source rock, gradation and moisture — granite and trap rock run heavier than limestone, and a rained-on load weighs more without covering more ground. Treat the tonnage as an estimate and expect the weigh ticket to differ.
Cost uses the price per ton you enter, so it reflects your local quarry rather than a national average. Delivery is not included.