Gravel calculator

Q: How many tons of gravel are in a cubic yard?

It depends on the stone. Clean #57 is about **1.35 tons**, crusher run about **1.48 tons** because the stone dust fills the voids, and pea gravel up to 1.6 tons for limestone-based product. Anyone quoting a single figure for "gravel" is rounding across a 15% spread.

Q: How much extra gravel should I order for compaction?

About **20–25% over the finished volume** for dense-graded base like crusher run, and 15–20% for clean crushed stone. Rounded decorative stone — pea gravel, river rock — is not compacted, so it gets no allowance. Skipping this is the most common reason people run short.

Enter the area and the finished depth you want. Two things decide the order: which stone you are buying, because density varies by about 15% between types, and whether it gets compacted — dense-graded base loses a fifth of its volume under the plate.

Area to cover Finished depth This is the depth after compaction. Driveway base 4–6 in, shed base 4 in, walkway 2–3 in. Stone type These are typical published figures. Your quarry can give you its own lb/cu yd — ask, because it is the number your ticket is priced on. Will it be compacted? Rounded stone (pea gravel, river rock) will not interlock, so it is not compacted and gets no allowance. Extra for spread and low spots % Gravel spreads past the edge and the subgrade always has dips. Use 10% on rough or unformed ground.

Gravel to order 9.56 tons

Loose cubic yards to order 6.48 cu yd

Finished volume in place 4.94 cu yd The gap between this and the order figure is the compaction allowance.

Loose volume in cubic feet 175 cu ft

One ton covers, at this depth 55 sq ft Useful when the quote is priced per ton.

How the number is worked out

Start with the volume you want in place: area × finished depth. A 20 ft × 20 ft driveway at 4 in is 400 × 0.333 = 133 cubic feet, or 4.94 cubic yards compacted.

Then two adjustments turn that into an order:

Compaction. Loose crushed stone carries 35–40% air voids. Run a plate compactor over it and that drops to 20–25%, which means the pile gets shorter. Dense-graded base has to be ordered about 25% over the finished volume — 4.94 becomes 6.2 cubic yards.
Weight. Yards sell gravel by the ton, so the cubic yards get multiplied by density. At 2,950 lb/cu yd for crusher run, 6.2 cubic yards is about 9.1 tons.

The compaction mistake

This is the error that actually costs people a return trip. Almost every gravel calculator takes your finished depth, converts it straight to volume, and stops. Order that figure and you will be short by a fifth — you get three-quarters of the driveway to the right depth and run out.

The related field mistake is placing it all at once. Compact in lifts of 4–6 inches of loose material, which settles to 3–4 inches. A 10 in base poured in one go leaves the bottom half loose no matter how long you run the plate over the top, and that is what makes a driveway develop ruts in year two.

Rounded stone is the exception. Pea gravel and river rock will not interlock, so they are never compacted and get no allowance at all. Applying a base compaction factor to pea gravel just over-orders.

Density is per stone, not universal

The other flattening you see everywhere is "gravel weighs about 1.4 tons per yard". Typical published supplier figures:

Clean #57 / 3/4 in stone — 2,700 lb/cu yd (1.35 ton). The fines are screened out, so it drains but will not compact tight.
Crusher run / #411 — 2,850–3,100 lb/cu yd (≈1.48 ton). Stone dust fills the voids, which is why it compacts and why it is heavier.
Pea gravel — 2,800–3,200 lb/cu yd. Limestone-based runs at the top of that range, granite-based at the bottom.
River rock — quoted anywhere from 2,500 to 3,500 lb/cu yd. Larger, rounder stone traps more air, so a yard of 5 in cobble can weigh less than a yard of pea gravel. This is the one figure worth getting from your own supplier.

Quarries quote dry weight. After a week of rain the same volume on your truck weighs 5–10% more.

What this does not include

Geotextile fabric under the base, which is what stops the stone migrating into soft subgrade.
The surface layer. A driveway is usually 4–6 in of base plus about 2 in of a finer top course — run the calculator twice.
Pipe displacement. For a French drain, the pipe occupies part of the trench and has to come off the volume.

Common cases

Questions people ask

How many tons of gravel are in a cubic yard?

It depends on the stone. Clean #57 is about 1.35 tons, crusher run about 1.48 tons because the stone dust fills the voids, and pea gravel up to 1.6 tons for limestone-based product. Anyone quoting a single figure for "gravel" is rounding across a 15% spread.

How much extra gravel should I order for compaction?

About 20–25% over the finished volume for dense-graded base like crusher run, and 15–20% for clean crushed stone. Rounded decorative stone — pea gravel, river rock — is not compacted, so it gets no allowance. Skipping this is the most common reason people run short.

How deep should a gravel driveway be?

Four to six inches of compacted base for cars, more over soft soil, plus roughly 2 in of a finer surface course on top. Place it in lifts of 4–6 in loose and compact each one; a single thick layer stays loose underneath and ruts within a season.

Is gravel sold by the ton or by the cubic yard?

Most quarries and landscape yards sell by weight, but you measure your project by volume, and the two only connect through the density of that particular stone. That mismatch is where ordering errors come from — work out cubic yards first, then convert with your supplier's own lb/cu yd figure.

Does pea gravel need to be compacted?

No. The stones are rounded, so there is nothing to interlock — running a compactor over it just pushes it aside. That is also why pea gravel stays loose underfoot and migrates out of an area without a solid edge restraint.

Last reviewed 2026-07-30