Gravel Calculator
Convert a driveway, path or garden bed into the tons of gravel, stone, sand or topsoil to order, with the density conversion quarries price by.
Length × width. For a circular area use π × radius².
2–3 in for a top-up, 4 in for a walkway, 6–8 in for a driveway base.
Density differs by material, which is why the same volume weighs different amounts.
Quarries sell by the ton but you measure by volume, so the conversion is the whole job. At 1.4 tons per cubic yard, one ton covers about 77 sq ft at this depth.
What this calculator does
Ordering aggregate involves a unit conversion that almost nobody does correctly in their head. You measure a driveway in feet, you specify a depth in inches, and the quarry quotes you in tons. Getting from the first to the last requires two divisions and a density figure that changes with the material.
This calculator does that conversion for crushed stone, pea gravel, sand and topsoil, and reports both the volume and the weight so you can check a supplier’s quote against your own measurements.
The arithmetic
cubic feet = area in square feet × (depth in inches ÷ 12)
cubic yards = cubic feet ÷ 27
tons = cubic yards × densityA 40 by 10 foot driveway at 4 inches deep:
- Area: 400 square feet
- Volume: 400 × (4 ÷ 12) = 133.3 cubic feet
- Cubic yards: 133.3 ÷ 27 = 4.94
- Crushed stone at 1.4 tons per yard: 6.9 tons
The 27 comes from a cubic yard being 3 × 3 × 3 feet. It is the same conversion used when calculating concrete in cubic yards, and it is the step people most often skip.
Why density differs by material
A cubic yard is a fixed volume, but what fills it varies:
| Material | Tons per cubic yard | Notes |
|---|---|---|
| Crushed stone | 1.4 | Angular, locks together, standard for bases |
| Pea gravel | 1.3 | Rounded, rolls underfoot, poor for driveways |
| Sand | 1.35 | Compacts tightly, used for paver bedding |
| Topsoil | 1.1 | Organic content makes it much lighter |
The practical consequence is that swapping pea gravel for crushed stone changes the tonnage by about 7% for the identical hole. If you order by weight against a volume you calculated with the wrong density, you will be short.
Angularity matters as much as weight. Crushed stone has fractured faces that interlock and stay put; pea gravel is rounded and migrates, which is why it scatters off a driveway and collects at the low end. For anything that carries vehicles, choose angular stone regardless of what looks better in the yard.
Ordering, delivery and the fees nobody quotes
Two costs sit outside the per-ton price:
Minimum loads. Most yards will not deliver under one or two tons, and some charge the minimum regardless. If you need half a ton, bagged stone from a big-box store is usually cheaper once delivery is counted.
Haul fees. Delivery is typically a flat charge by distance, not per ton, which means the per-ton economics improve sharply with volume. Two separate three-ton deliveries can cost noticeably more than one six-ton drop.
There is also a practical ceiling: a standard dump truck carries somewhere in the region of 10 to 14 tons, so larger jobs arrive in multiple loads and the quote should say so.
What this leaves out
Be clear about the limits of a volume estimate:
- Compaction. Aggregate settles as it is driven on. A driveway base compacts meaningfully, and professionals commonly add 10–20% for it. This calculator reports loose volume, so add your own allowance for a base course.
- Subgrade irregularity. The depth you enter is assumed uniform. Ruts, soft spots and a crowned centre all consume more material than a flat plane.
- Edging and containment. Without a border, gravel migrates outward and the surface thins. That is a maintenance cost, not a delivery quantity.
- Geotextile and base layers. A proper driveway is usually two materials — a coarse base and a finer surface course. Calculate each layer separately.
- Local density variation. Quarry rock differs by region. If a supplier publishes a density for their product, prefer it over the averages here.
Checking a quote
The fastest sanity check is the coverage figure. One ton of crushed stone covers roughly 115 square feet at 2 inches, 77 at 3 inches, and 57 at 4 inches. If a supplier’s tonnage implies coverage wildly different from that, one of you has the depth wrong.
For related jobs, the mulch calculator handles bark and compost, which are sold by volume rather than weight, and the concrete calculator covers slabs and footings where the same cubic-yard conversion applies. If you are building a base for a patio, the flooring calculator handles the surface material above it.
How this is calculated
cubic feet = area (sq ft) × depth (in) ÷ 12 cubic yards = cubic feet ÷ 27 tons = cubic yards × density Density (tons per cubic yard): crushed stone 1.4, pea gravel 1.3, sand 1.35, topsoil 1.1.
Frequently asked questions
- Why is gravel sold by the ton when I measured a volume?
- Quarries weigh trucks across a scale, so weight is the only figure they can bill accurately. Volume varies with how loosely the load is piled, weight does not. You measure volume because that is what fills your driveway, so a density conversion sits between the two.
- How deep should gravel be?
- Two to three inches refreshes an existing surface. A walkway or garden path wants about four inches. A driveway needs six to eight inches, usually in two layers with a coarser base underneath and a finer top course. Deeper than that is rarely useful unless you are correcting drainage.
- How much does a ton of gravel cover?
- At two inches deep a ton of crushed stone covers roughly 115 square feet. At four inches it covers about 57. The calculator shows this figure for your chosen depth and material, which is the quickest way to sanity-check a supplier's quote.
- Is the weight affected by rain?
- Yes, and it is not trivial. The densities used here are dry-load averages. A load taken after heavy rain can weigh several percent more for the same volume, so you pay for water. Ordering by volume where a supplier allows it avoids the issue.
- Do I need landscape fabric underneath?
- For paths and decorative beds it is worth it, because it slows the gravel sinking into soft ground and suppresses weeds. Under a driveway a proper compacted base matters far more than fabric. Neither changes the quantity of stone you order.