How many tons of gravel in a cubic yard?

The measured answer, by rock, from named quarries

Alabama DOT's List I-1 publishes a loose unit mass for every approved aggregate source in the state — the actual weight of a measured volume of that producer's stone, source by source. Converted to a cubic yard:

Material	Sources	Tons per loose cubic yard
Natural gravel	6	1.35 – 1.44
Crushed gravel	32	1.15 – 1.42
Crushed limestone	68	1.01 – 1.32
Crushed granite	19	1.08 – 1.23
Crushed sandstone	9	1.07 – 1.17

The familiar "1.4 tons per yard" is the natural gravel row. It is the only material on the list that reliably reaches it, and it is not what most people are buying for a driveway base. Crushed stone measures lower — often a fifth lower.

The spread inside a single rock type is the other half of the problem. Take crushed limestone from one company in one state: Vulcan Materials' Tuscumbia quarry is listed at 85 lb per cubic foot, Calera at 90, Helena at 95. That is 2,295, 2,430 and 2,565 lb per cubic yard from the same producer and the same rock — an 11% spread that no single published figure can carry.

It is mostly packing, not the weight of the rock

The obvious explanation is that granite is a lighter rock than limestone. It is not. Alabama lists granite at a median bulk specific gravity of 2.653 against limestone's 2.680 — a fraction of a percent apart, nowhere near the difference in what a yard of each weighs.

Wisconsin DOT's Pit and Quarry Listing lets you put a bound on that. Parsing all 3,618 coarse-aggregate test records in the 2026 edition gives a median bulk specific gravity of 2.672 and a middle-90% band of 2.541 to 2.786 — a 9.6% spread in the rock itself. So the rock explains about ten points and the rest is air: angular crushed fragments bridge against each other and leave voids that rounded gravel does not.

That also fixes a ceiling. A cubic yard with no air in it at all weighs the specific gravity times 62.4 lb per cubic foot times 27, which across that Wisconsin band is 2.14 to 2.35 tons. Nothing you buy can exceed it, and the gap between the ceiling and your quote is the air you are paying to haul. A yard quoted at 2,700 lb is 40% air; at 2,950 lb, 34%.

One caveat, and what to ask for instead

A loose unit mass is stone poured into a measure, not stone that has ridden in a truck and settled. A delivered, vibrated load sits denser, which is why supplier figures generally run above the DOT numbers. Treat the table as the floor and the solid-rock ceiling as the roof — the true figure for your ticket is between them, and nearer the floor for angular stone, which locks up with more voids than a rounded stone of the same nominal size.

So do not ask a quarry what a yard of gravel weighs. Ask for the unit weight of the specific gradation you are buying, and whether it is the loose or the compacted figure. Those two questions get you a number that is actually about your material, which is more than any rule of thumb can offer.

Sources, both read directly: Alabama DOT, List I-1 Sources of Coarse and Fine Aggregates (revised 7/7/2026; "Loose Unit Mass" and "Bulk Specific Gravity" columns) and WisDOT Pit and Quarry Listing for Use in 2026 ("Coarse Sp. Gravity OD").