Gravel driveway calculator

Ordered loose, laid compacted. This applies the difference.

Material
Units

Per layer. Deep drives go down in lifts.

Between 1.20 and 1.40.

Add a price

Quarries quote per ton delivered; haulage often outweighs the stone.

Enter your driveway size to get a tonnage.

Ordering gravel for a driveway

Every driveway calculation has a step most tools leave out. You measure the finished, compacted layer, but the quarry sells you loose material straight off the pile. Loose stone occupies substantially more space than the same stone rolled and driven on, so ordering the compacted figure leaves you short every single time. That gap is a fifth to two fifths of the load.

Compacted cubic feet = length × width × (depth ÷ 12) Loose cubic feet = compacted cubic feet × compaction factor Cubic yards = loose cubic feet ÷ 27 Tons = cubic yards × density ÷ 2000
  • compaction factor — 1.20 to 1.40, how much the material shrinks once rolled
  • density — pounds per cubic yard, which varies by stone type and moisture
  • 2,000 — pounds in a US short ton, the unit quarries invoice in
  • depth — thickness of one layer, not the whole build-up

Worked example: a 40 by 10 foot drive, 4 inches deep

40 × 10 × (4 ÷ 12) = 133.33 compacted cubic feet 133.33 × 1.25 = 166.67 loose cubic feet 166.67 ÷ 27 = 6.17 cubic yards 6.17 × 2700 ÷ 2000 = 8.33 tons

Order 6.17 yards and you will lay roughly three and a quarter inches, not four. The extra 1.5 yards is not waste — it is the air that gets driven out of the material as it beds down.

Why density is given as a range

Crushed stone runs 2,600 to 2,900 pounds per cubic yard depending on the rock and how wet it is. This calculates at the published typical of 2,700 and shows the spread rather than hiding it. Across a large order the ends of that range differ by most of a ton, so ask your supplier for theirs.

Common mistakes

  • Ordering the compacted volume. The single most common error, and it under-orders by 20 to 40 percent.
  • Treating tons and yards as interchangeable. A yard of stone is roughly 1.35 tons. Quoting one and ordering the other is an expensive slip in either direction.
  • Calculating one thick layer. Anything over about four inches goes down in lifts and each is compacted separately.
  • Forgetting the sub-base. A drive that will carry cars needs a coarse base under the decorative top. Calculate the layers separately; they use different material.

When these numbers do not apply

  • Pea gravel and sand. Rounded material barely locks together and does not compact like angular crushed stone, so the published compaction factor does not transfer.
  • Soft or boggy ground. Stone pressed into mud vanishes. Ground that pumps needs geotextile before any figure here means much.
  • Recycled and crushed concrete. Densities differ from quarried stone and vary batch to batch.
  • Loose surface top-ups. If you are not rolling it, skip the compaction factor entirely and order the plain volume.

Common questions

How many tons of gravel do I need for a driveway?

A 40 by 10 foot drive at 4 inches works out around 8.3 tons of crushed stone once compaction is allowed for. Halve the depth and you roughly halve the tonnage.

What is a compaction factor?

The ratio between loose material and the same material once rolled. A factor of 1.25 means you must order 25 percent more than the finished layer measures, because that much air is driven out during compaction.

How deep should a gravel drive be?

Four inches is a common figure for a top layer over an existing base. A new drive carrying vehicles needs a deeper build-up in separate lifts, and the total depends on your ground conditions.

Should I order in tons or yards?

Whichever your supplier quotes in, and check which before you phone. This tool gives both from the same calculation so you can convert the quote rather than the load.

Why does the weight change with the weather?

Wet stone carries water, and water is heavy. Buying by the ton after rain means paying for moisture, which is one argument for buying by the yard where you have the choice.

Sources

Crushed stone / gravel density
2600–2900 lb/yd3
  • Industry reference range — varies by supplier and moisture content; verify against your supplier's published figure Awaiting verification against the published data sheet

Density varies by stone type and moisture content and must be surfaced to the user as a range. Compaction factor applies to loose volume for base course. No waste factor was supplied for this material.

Pea gravel density
2700–2850 lb/yd3
  • Industry reference range — varies by supplier and moisture content; verify against your supplier's published figure Awaiting verification against the published data sheet

No typical value was supplied for pea gravel, so none is stored. Using a computed midpoint would be an invented constant.

Bedding sand density
2600–2900 lb/yd3
  • Industry reference range — varies by supplier and moisture content; verify against your supplier's published figure Awaiting verification against the published data sheet

No typical value was supplied, so none is stored.

Unit conversions are exact by definition and need no source.

How we choose and cite these figures

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