Pea gravel looks like a minor variation on gravel — smaller, rounder, friendlier. For ordering purposes it is a different material: its own density, its own coverage, and a firm opinion about where it should never be used. This guide runs pea gravel on its own numbers, the way the yards that sell it do.

Pea gravel density: why it gets its own number

The pea gravel density used by suppliers and by the Gravel Calculator is 1.38 tons per cubic yard — 2,760 lb, or about 102 lb per cu ft. Published figures cluster between roughly 2,600 and 2,800 lb per yd³; 2,760 sits sensibly inside that range. Why not just use gravel’s 1.40? Because pea gravel’s stones are rounded and nearly uniform — around ⅜ inch across, the size of the peas that named it. Angular crushed stone nests and locks, so a yard of it packs tighter and heavier for its size; rounded peas leave regular voids, which is also why a pea gravel surface stays loose and mobile underfoot. That mobility is the material’s character: wonderful in a path or a play area, hopeless as a driveway surface or a structural base, where the whole point is that the layer must not move. Buy it for the jobs its shape suits, and its slightly lighter density is a fair trade.

The weight questions, answered once

Used as a pea gravel weight calculator, the arithmetic is two multiplications. One cubic yard weighs 2,760 lb (1.38 tons). One ton of pea gravel is the reciprocal: 1 ÷ 1.38 = 0.72 cubic yards — about 19.6 cu ft. In bags: a cubic yard is 54 of the standard 0.5 cu ft bags, and at this density each bag works out to about 51 lb, the familiar ~50 lb bag — so a ton is roughly 39–40 bags by weight, and the bag count for any project is just its cu ft divided by 0.5. If your yard sells pea gravel by the scoop or the yard rather than the ton, run the estimate yards-first — the “pea gravel calculator yards” workflow: compute the volume, order the yards, and let the tons be the cross-check instead of the order line. Either direction, one density — 1.38 — does all the converting.

Coverage: what a ton and a yard actually spread

Coverage is volume wearing a depth. A cubic yard of anything covers 324 sq ft at 1 inch; pea gravel’s coverage per ton is that same table scaled by 0.72:

Computed at 1.38 tons per yd³ and rounded to the nearest square foot.

A word on why other charts disagree with this one — politely, and by a little. A supplier who runs pea gravel at 1.35 tons per yd³ will tell you a ton covers 120 sq ft at 2 inches; one who runs it at 1.40 will say 116. This table says 117, at 1.38. All three are the same geometry wearing different density assumptions, and none is a lie — but they are not interchangeable mid-project. Pick one density, ideally your own yard’s, and run the whole estimate on it: the worked projects below, the coverage table and the calculator on the hub all use 1.38 here, so the numbers agree with each other, which is the only kind of agreement an order can actually use.

Three worked projects

A 10 × 10 ft patio, 3 inches deep: 100 sq ft × 0.25 ft = 25 cu ft = 0.93 yd³, which is 1.28 tons — or exactly 50 bags of 0.5 cu ft. This is the classic pea gravel job: small, flat, and at the size where bagged and bulk genuinely compete. A 15 × 15 ft play area, 3 inches deep: 225 × 0.25 = 56.25 cu ft = 2.08 yd³ ≈ 2.88 tons — bulk territory; have it tipped, not bagged. A 20 × 3 ft garden path, 2 inches deep: 60 sq ft × (2 ÷ 12) = 10 cu ft = 0.37 yd³ ≈ 0.51 tons, or 20 bags — a Saturday-morning job. Run your own measurements through the pea gravel estimator in the Gravel Calculator (choose Pea gravel in the material list) and it applies the 1.38 density and both bag counts for you.

Two pea-gravel habits save rework. Contain it: rounded stone travels, so edging — metal, stone or timber — is not decoration, it is what keeps 3 inches at 3 inches. Bed it: landscape fabric underneath stops the peas migrating down into the soil and the soil pumping up into the peas; without it a path can lose a visible share of its depth in a single wet season.

What it costs: the method, not a price list

A pea gravel cost calculator is honest only as a method, because the prices are local and seasonal. The method is two multiplications: bulk cost = tons × the yard’s price per ton (plus the delivery fee, and remembering many yards price delivery per load, not per ton), and bagged cost = bags × the store’s price per bag. One illustration, with deliberately round, illustrative prices — not quotes: the 10 × 10 patio above needs 1.28 tons, so at an illustrative $50 per ton the stone is about $64 in bulk; its 50 bags at an illustrative $5 a bag come to about $250. That four-to-one gap is typical of the relationship, which is why the bag-versus-bulk breakpoint sits near a ton — below it, you are paying for convenience you may actually want; above it, you are paying for packaging. Get your yard’s real per-ton figure and your store’s real bag price and the same two lines settle the question for your project.

Topping up, and the jobs pea gravel quietly suits

Most pea gravel orders are not new installations — they are top-ups, and the math is the depth difference, not the full depth. Bringing a settled 10 × 10 ft patio from 1 inch back up to 3 means adding 2 inches: 100 sq ft × (2 ÷ 12) = 16.7 cu ft = 0.62 yd³ ≈ 0.85 tons, or 34 bags. Rake the existing stone level and measure in a few spots before ordering; pea gravel settles unevenly, and the low corner is the depth that matters. Beyond patios and paths, the same mobility that disqualifies pea gravel from driveways suits it to dog runs (it hoses clean and does not churn to mud), drainage trenches and the surround of perforated pipe in light-duty garden work (water moves freely through the rounded voids), and as a permanent mulch alternative in dry beds — it never decomposes or blows away, though in exchange it feeds the soil nothing and runs hot in full sun, which the plants get a vote on.

What size is pea gravel, and how does it age?

Standard pea gravel is ⅜ inch (about 9.5 mm) — the size of the peas in its name — though some yards stock a finer ¼-inch grade and a chunkier ½-inch one under the same label, which is why the ticket’s size line is worth a glance: coverage maths does not care (a yard is a yard), but the feel underfoot does, and the finer grade packs a touch denser than the coarse. Once down, pea gravel ages on three fronts. It migrates — kicked, tracked and washed toward edges and low spots, which edging and the occasional rake-back answer. It settles — the first season’s rains shuffle the peas into their voids, and a fresh 3 inches can read as 2½ by autumn; the top-up section above exists precisely because this is normal, not a short delivery. And it weeds — seeds land in the voids, so the fabric layer underneath earns its money twice: once stopping the stone sinking, once stopping roots anchoring. None of this is a defect. It is the maintenance profile of a loose, rounded material — a rake and a small top-up every year or two, against zero sealing, zero cracking and zero replacement, which is the trade its owners happily signed up for.

Buying it well: bulk, bags and the ticket

Three buying notes close the guide. Bulk is weighed, bagged is counted — a bulk load’s ticket shows gross, tare and net weight, and the net is what you bought; glance at it, because it is also your receipt if the load looks light in the pile. Moisture rides along: stone sold by weight carries its weather with it, and a yard of pea gravel after a wet week sits at the heavy end of its 2,600–2,800 lb range — one reason small jobs sometimes favour bags, whose weight is printed and fixed. Leftovers keep: unlike soil or mulch, pea gravel does not rot, settle into nothing or lose its looks in a heap; a modest surplus in a corner bin is next year’s top-up already paid for. Buy the project, then, not the panic — measure, convert at 1.38, add the usual few percent, and let the delivery match the arithmetic.

Pea stone, pea rock: the other name tags

Depending on the region and the yard, the identical material is sold as pea stone or pea rock — a pea stone calculator or a pea rock calculator is this same page with the same density, because the stone does not change with its label. What to check on the ticket is the size (⅜ inch is standard pea) and that the stone is washed and rounded, not a crushed ⅜-inch product, which behaves — and packs — differently.

Frequently asked questions

How much does a cubic yard of pea gravel weigh?

2,760 lb — 1.38 tons — at the standard working density. Published figures for pea gravel run from about 2,600 to 2,800 lb per cubic yard depending on the stone and its moisture, so treat 2,760 as the planning number and the scale ticket as the final one.

How many bags of pea gravel are in a cubic yard?

54 of the standard 0.5 cu ft bags — a cubic yard is 27 cu ft, and 27 ÷ 0.5 = 54. At pea gravel’s density each of those bags weighs about 51 lb, which matches the familiar ~50 lb bag.

How much does a ton of pea gravel cover?

About 117 sq ft at 2 inches deep, 78 sq ft at 3 inches, and 59 sq ft at 4 inches. A ton of pea gravel is 0.72 cubic yards, and coverage is that volume spread at your depth.

Is pea gravel good for a driveway?

Not as the driving surface. Pea gravel’s stones are rounded, so they roll and migrate under tyres instead of locking together — ruts and scattered stone are the predictable result. It is excellent for paths, patios, play areas and drainage; a driveway wants angular crushed stone on a compacted road-base layer.

How deep should pea gravel be?

Two to three inches for paths and patios — deep enough to cover and cushion, shallow enough to walk on comfortably. Play areas are often spread deeper for cushioning; check the equipment maker’s fall-height guidance for the figure your setup needs.