Article — Gravel Calculator
Gravel calculator: cubic yards, tons, and cost for any project
A gravel calculator converts length, width, and depth into the cubic yards or cubic metres of gravel you need to fill the area — plus the weight in tons. The core formula is volume = length × width × depth, with unit conversion applied. Standard crushed gravel weighs 1.5 short tons per cubic yard (about 1,780 kg per cubic metre). A typical 20 × 30 ft driveway at 4 inches deep needs 7.4 cubic yards or 11.1 tons of gravel.
This calculator handles all common gravel types — crushed stone, pea gravel, river rock, limestone, marble chips — with their respective densities. Inputs accept feet, inches, yards, metres, or centimetres. Outputs cover both US customary (cubic yards, short tons, square feet) and metric (cubic metres, metric tons, square metres) so the result fits whichever supplier you call.
The gravel volume formula
In US units: cubic yards = (length in ft × width in ft × depth in inches) ÷ 324. The 324 is 27 cubic feet per yard multiplied by 12 inches per foot. The figure usually rounds messily because depth is typically given in inches while length and width are in feet.
yd³ = (L_ft × W_ft × D_in) / 324 US unitsm³ = L_m × W_m × D_m metric units1 yd³ = 0.7646 m³ conversiontons = yd³ × 1.5 crushed gravel densityarea covered = 324 / D_in ft² per yd³The metric version is cleaner: cubic metres = length × width × depth, all in metres. A 6 m × 3 m × 0.1 m driveway is exactly 1.8 m³. Multiply by 1.78 to get tons (using crushed-gravel density). The metric system avoids the unit-mixing arithmetic, which is why most non-US suppliers quote in cubic metres only.
Gravel types and densities
Density varies by about 20% across gravel types, which directly changes weight and delivery cost. Pea gravel is the lightest commercial product at 1.4 short tons per cubic yard. Marble chips and dense crushed limestone reach 1.6 t/yd³.
- Pea gravel = 1.4 t/yd³ (1,660 kg/m³), rounded, decorative, 3/8 to 5/8 inch
- Crushed gravel = 1.5 t/yd³ (1,780 kg/m³), angular, 3/4 inch, default for driveways
- Crushed limestone = 1.55 t/yd³ (1,840 kg/m³), light grey, dense, pathways and bases
- Quarry process (QP) = 1.45 t/yd³ (1,720 kg/m³), mixed angular + stone dust, compactable
- River rock = 1.35 t/yd³ (1,600 kg/m³), smooth, decorative, 1 to 3 inch
- Marble chips = 1.55 t/yd³ (1,840 kg/m³), white, premium landscaping
The density difference matters most for delivery cost. A truckload caps at 22 to 25 tons. For pea gravel that means about 16 cubic yards per truck; for crushed limestone it is closer to 14. If your project sits at the upper end of a truckload, choosing a lighter gravel can save a second delivery fee.
Gravel for driveways
Driveway gravel goes in two layers. The base layer is 3 to 4 inches of #3 or #4 crushed stone (1 to 2 inch angular pieces) for drainage and load distribution. The top layer is 2 to 3 inches of #57 stone or quarry process for a stable driving surface. Total depth is 5 to 7 inches for residential use, 8 to 12 inches for heavy vehicles or year-round freeze-thaw climates.
Worked example: a 20 × 30 ft residential driveway at 6 inches total (3 in base + 3 in top) needs (20 × 30 × 6) ÷ 324 = 11.1 cubic yards. At 1.5 tons per yard, that is 16.7 short tons. At a typical $20/ton blended price plus $100 delivery, the total is about $440. Order an extra 10% (12.5 yd³, 18.7 tons) to allow for compaction and edge spillover.
Gravel for patios and pathways
Decorative areas use pea gravel or river rock at shallower depth. A pathway needs only 2 to 3 inches; a sitting area or fire-pit base needs 3 to 4 inches. Underlay with landscape fabric to keep the gravel from migrating into the soil over time.
For walkability, choose pea gravel between 3/8 and 5/8 inch. Anything smaller migrates into shoe treads; anything larger shifts underfoot and feels unstable. A 4 ft × 20 ft pathway at 2 inches deep needs (4 × 20 × 2) ÷ 324 = 0.49 yd³ — well under a full ton. Most suppliers have a 1-ton minimum, so consider doing two pathways or a patio in the same order.
Pea gravel patios should be edged with steel, brick, or treated lumber to keep the surface contained. Without edging, the gravel migrates outward into surrounding turf or beds at a rate of about 1 to 2 inches per year. The lost volume needs to be topped up annually, adding to long-run cost.
Gravel for French drains and fill
French drains and drainage trenches use angular crushed stone (#57 or #67 grade) because the angular pieces lock together and maintain void space for water flow. Rounded gravel collapses under load and reduces drain capacity within a few years.
A typical French drain trench is 12 inches wide and 18 inches deep, filled with 12 inches of gravel above a 6-inch sand or pea-gravel base around the perforated pipe. For a 50 ft run, gravel volume is 50 ft × 1 ft × 1 ft = 50 cubic feet = 1.85 cubic yards = 2.8 short tons of crushed stone. Add the sand or pea-gravel bedding separately.
Rounded gravel does not compact — it rolls. For retaining-wall backfill, foundation drainage, or any application that needs to support load, only use angular crushed stone. The interlocking shape gives strength that rounded river rock simply cannot provide, no matter how thick you lay it.
Gravel cost per ton and per yard
2025 wholesale gravel prices in the US run $10 to $60 per short ton at the quarry, depending on type and region. Add 30 to 100% for retail and delivery once the material reaches a residential lot. Quarry process is the cheapest at $10 to $18 per ton; marble chips and decorative stone top the range at $40 to $60.
Gravel is one of the largest non-fuel mining products in the world. The US alone produces about 1 billion tons of crushed stone and 800 million tons of sand and gravel every year, according to the US Geological Survey. The combined value exceeds $30 billion. Most of it is consumed within 50 miles of where it is quarried, because transport costs scale with weight and gravel is heavy relative to its market price.
Delivery typically adds $50 to $200 per truckload, with most companies charging by mileage past a 10 to 15 mile free zone. For projects under 1 ton, buying bagged gravel from a hardware store costs more per ton but eliminates the delivery fee and is easier to handle. Bulk delivery makes sense above 2 to 3 tons.
Common gravel calculation mistakes
Most gravel ordering errors come from unit confusion. The depth is usually given in inches while the length and width are in feet, and people forget the conversion. Order short and you make a second delivery trip; order long and you have a pile of expensive surplus.
A common error is reporting the volume of a 100 ft² × 4 in deep area as 33 cubic feet (correct), then ordering 33 cubic yards (wrong). The correct yardage is 33 ÷ 27 = 1.23 yd³. The error is a factor of 27 — large enough that a single mistake can cost thousands. Always check whether your supplier quotes by the yard or by the foot.
The other frequent mistake is forgetting compaction. Fresh-laid gravel settles 10 to 15% in the first year, more if the surface sees vehicle traffic or freeze-thaw cycles. Build the settling into your order: if the calculator says 10 cubic yards, order 11 or 12 to maintain the target depth after settling.
Gravel maintenance and refresh cycles
A gravel driveway needs a 1 to 2 inch top-up every 2 to 3 years to maintain depth as material works into the soil or migrates off the edges. A decorative pea-gravel patio needs less topping but more raking, since the rounded stones shift visibly under foot traffic. Plan a full refresh — fresh top layer and re-grading — every 5 to 7 years for vehicle surfaces.
The lifetime cost of gravel paving is well below asphalt or concrete despite the maintenance. A 600 sq ft driveway in gravel costs about $400 to install and $50 to $80 per year to maintain. Asphalt costs $3,000 to $5,000 upfront with resurfacing every 10 to 15 years. Over 30 years, gravel comes out roughly half the price.