Gravel Driveway Calculator
Work out the yards and tons of stone a gravel driveway needs, layer by layer.
Quick estimating rule of thumb
For a gravel driveway: area (sq ft) × depth (in) ÷ 324 = cubic yards per layer. Budget 8 to 12 inches total in three layers: 4 inches of base stone, 3 of mid-size, 2 to 3 of dense-graded surface course. One yard covers about 80 sq ft at 4 inches. Order 15% extra, not 10: driveway stone is compacted deliberately and then again by every vehicle.
This gravel driveway calculator turns the driveway footprint and the depth of stone into the cubic yards and tons you need to order. Enter the whole build-up at once, or run it three times (once per layer), because a driveway that lasts is not one depth of one stone.
A driveway is the job where under-ordering hurts most: the truck leaves, the base is short, and the next delivery carries a second haul fee. The tool defaults to a 15% allowance rather than the usual 10%, because driveway stone compacts under a plate compactor and then again under every vehicle that uses it.
How thick should a gravel driveway be?
Plan on 8 to 12 inches of total stone over undisturbed subsoil, built in three layers. A coarse 3 to 4 inch base stone goes down first at 4 inches deep, then 3 inches of #57 or similar mid-size stone, then 2 to 3 inches of a dense-graded surface course such as 3/4 minus or #411 that locks together under traffic. On firm, well-drained ground you can cut that to 6 inches total; over clay that holds water, 12 inches plus a geotextile fabric is the honest figure.
The common mistake is a single 4-inch layer of pretty surface stone over bare soil. It looks finished on day one and ruts by the first wet spring, because nothing underneath is spreading the load. If the budget only covers one layer, spend it on the base and live with a rough surface for a season.
Running the numbers per layer
Work one layer at a time and add the results, because each layer is a different stone at a different price. A 40 ft by 12 ft driveway is 480 square feet. At 4 inches of base that is 5.93 cubic yards, or about 8.9 tons of road base at 1.5 tons per yard. The 3-inch middle layer adds 4.44 yards, and a 2-inch surface course adds 2.96 yards, for roughly 13.3 cubic yards and 18 tons of stone in total, before the allowance.
That total is more than a single tandem dump truck carries, so the delivery is going to be two trips or two trucks whatever you do. Once you know that, ask the yard whether splitting the order by stone type costs anything extra: usually it does not, and it means each layer arrives in its own pile rather than mixed.
Width, turnarounds and the bits people forget
A single-car driveway is 10 to 12 feet wide, a double 20 to 24. Add the flare at the road, any parking apron, and the turnaround: a three-point turn needs about 20 feet of depth beyond the driving lane. These are the areas left out of a first estimate and they are frequently a third of the job. Run the tool once per rectangle and add them up, or use the quantity field for identical bays.
Gravel also migrates. A driveway loses stone to the road edge, to snow ploughing, and into the soil below, so budget a top-up load of surface stone every three to five years. That is not waste on this order, but it is worth knowing before you compare gravel against asphalt on price.
Costing a gravel driveway against the alternatives
Gravel is the cheapest driveway surface to install by a wide margin: commonly $1 to $3 per square foot in material and machine time, against $7 to $13 for asphalt and $8 to $18 for poured concrete. The trade is maintenance: gravel wants grading every year or two and a top-up load every three to five years, where asphalt is sealed every few years and concrete is left alone.
Where gravel loses is on a steep grade and in snow country. Above about a 10% slope, surface stone walks downhill with every rain and every tyre; above 15%, plan on a paved apron at the steepest section. Snow ploughing scrapes stone into the verge, so a ploughed driveway in a cold climate loses material two or three times faster than the same driveway in a mild one.
Common driveway-ordering mistakes
Estimating only the driving lane. The road flare, the parking apron and the turnaround are frequently a third of the area and are almost always left out of a first estimate.
Ordering the finished depth. Driveway stone compacts 15 to 20%, so a 4-inch finished base needs about 5 inches spread loose. Order for the loose depth.
Buying decorative stone for the surface. Rounded river rock and washed pea gravel never lock up under traffic; they rut and roll. The surface course wants a dense-graded angular stone with fines.
Skipping the fabric over clay. Without a geotextile, traffic pumps base stone down into soft subsoil and the driveway sinks in patches within two seasons.
No edge restraint. Gravel with nothing to hold it migrates into the lawn. Timber, steel edging or a shallow trench pays for itself in stone not lost.
| Material | lb / ft³ | tons / yd³ | Sold by | Typical use |
|---|---|---|---|---|
| Pea gravel (3/8″, rounded) | 100–105 | 1.35 | ton or yd³ | Paths, patios, dog runs, drainage |
| #57 crushed stone (3/4″, washed) | 100–105 | 1.35 | ton | Drainage, slab sub-base, French drains |
| 3/4″ minus / dense-grade | 105–115 | 1.45 | ton | Driveway base, paver base, road pack |
| Crushed concrete (RCA) | 100–110 | 1.35 | ton | Driveway base, structural fill (cheaper) |
| River rock (1–3″) | 95–105 | 1.40 | ton or yd³ | Dry creek beds, borders, xeriscape |
| Decomposed granite | 110–120 | 1.50 | ton | Paths, patios, natural-look driveways |
| Road base / Class 5 | 110–120 | 1.50 | ton | Compacted base under pavers, slabs, drives |
Background reading: gravel cost per ton and per yard and how deep should gravel be.
Frequently asked questions
How much gravel do I need for a driveway?
For a 4-inch layer, roughly one cubic yard for every 80 square feet. A 40 ft by 12 ft driveway is 480 square feet, so about 6 cubic yards per 4-inch layer, or 8 to 9 tons. A full three-layer build-up on that driveway is around 13 cubic yards and 18 tons.
How thick should a gravel driveway be?
Eight to twelve inches of total stone in three layers: 4 inches of coarse base, 3 inches of mid-size stone, and 2 to 3 inches of dense-graded surface course. Six inches is acceptable on firm dry ground; over clay, go to 12 inches with geotextile fabric underneath.
What is the best gravel for a driveway?
A dense-graded stone with the fines left in, sold as 3/4 minus, #411, or crusher run. The fines let it compact into a hard surface. Washed stone such as #57 stays loose and rolls under tyres, which makes it a good drainage or base layer but a poor surface.
How many tons of gravel for a 100 foot driveway?
At 12 feet wide and 4 inches deep, a 100-foot driveway is 1,200 square feet, about 14.8 cubic yards, or 21 tons of dense-graded stone. A full three-layer build-up is closer to 33 cubic yards and 47 tons.
How much does a gravel driveway cost?
Material runs roughly $15 to $60 per cubic yard depending on the stone and your region, so a 480 square foot driveway with a full build-up is $200 to $800 in stone plus delivery. Enter your local price per yard or per ton to get a figure for your order.
Do I need fabric under a gravel driveway?
Over clay, silt or anything that stays wet, yes. A woven geotextile stops the base stone from being pumped down into the soft subsoil by traffic, which is the usual reason a driveway sinks in patches. Over sand or firm gravelly subsoil you can skip it.
How wide should a gravel driveway be?
Ten to twelve feet for one car, twenty to twenty-four for two abreast. Add the flare where it meets the road and any turnaround, and calculate those as separate rectangles: they are commonly a third of the total area.
Should I add extra for compaction on a driveway?
Yes, 15% rather than the usual 10%. Driveway stone is compacted deliberately with a plate compactor or roller and then compacts further under vehicles. A layer spread 4 inches loose finishes closer to 3.25 inches.
How often does a gravel driveway need topping up?
Every three to five years for a surface course, sooner if it is ploughed in winter or the grade is steep. A top-up is usually 1 to 2 inches of surface stone, which is about 3 cubic yards on a 480 square foot driveway.
How many dump truck loads is a gravel driveway?
A standard tandem-axle truck carries 10 to 14 cubic yards, or 14 to 20 tons. A 480 square foot driveway with a full three-layer build-up is about 15 yards after the allowance, so two loads, or one load per stone type if you split the order.
Can I put new gravel over an old gravel driveway?
Yes, and it is the cheapest way to rescue one. Grade the existing surface, fill the potholes with base stone and compact, then add 2 to 3 inches of fresh dense-graded surface course. On a 480 square foot driveway that top-up is about 3 to 4.5 cubic yards.
How much gravel for a 20x20 parking pad?
400 square feet at 4 inches is 4.94 cubic yards, about 7.4 tons of road base. A full 8-inch build-up doubles that to roughly 10 yards and 15 tons.
Do I need to compact a gravel driveway?
Yes, in lifts of no more than 3 to 4 inches with a plate compactor or a roller. Compacting each layer as it goes down is what produces a surface that sheds water instead of holding it in ruts. A driveway left to compact under traffic alone settles unevenly.
What slope does a gravel driveway need?
A crown or cross-fall of about 2%, roughly 1/4 inch per foot, so water runs off the surface rather than sitting in the wheel tracks. A flat gravel driveway holds water, and standing water is what turns a rut into a pothole.