Gravel & Aggregate Calculator
Enter your area, depth, and stone type to get cubic yards and tons — tonnage depends on density, so the stone type matters.
How much gravel do I need?
Gravel is sold by the ton; tonnage depends on the stone's density, so pick the type (default ~1.4 tons/yd³). A 10% waste allowance covers compaction and uneven ground; driveway surface is usually ~4 in. Cost is an estimate (as of June 2026) — delivery is typically extra.
New here? Read How much gravel for a driveway?
How the gravel estimate works
- Volume = area × depth ÷ 324 = cubic yards (same 324 identity as mulch).
- Tons = cubic yards × the stone's density. Crushed stone runs about 1.4 tons per cubic yard; crusher run is heavier (~1.6), large rock lighter (~1.25).
- 100 ft² at 4″ = 1.23 yd³ × 1.4 ≈ 1.7 tons, then add ~10% for compaction.
Gravel is sold by the ton, so we round up to the half-ton. Density varies by stone type, gradation, and moisture — pick the closest match.
Why density is a required input, not a hidden default
Most gravel calculators quietly assume one density and hand you a tonnage. That is where the errors come from. Volume is geometry and never changes — a 12 × 40 ft drive at 4″ is 5.93 cubic yards whatever you fill it with. Weight is a property of the rock. Here is that identical hole priced against every stone type in our table:
| Stone type | Tons per yd³ | Tons to order | Sq ft covered per ton | Est. cost | Confidence |
|---|---|---|---|---|---|
| Crushed stone (generic) (default) | 1.4 | 9.5 t | 58 ft² | $475 | corroborated |
| Crushed gravel (¼–2 in) | 1.5 | 10 t | 54 ft² | $500 | corroborated |
| Crusher run / road base | 1.6 | 10.5 t | 51 ft² | $525 | corroborated |
| Large rock (2–6 in) | 1.25 | 8.5 t | 65 ft² | $425 | corroborated |
| Crushed limestone (dense) | 1.69 | 11.5 t | 48 ft² | $575 | low |
Same hole, same depth, and the order swings from 8.5 tons to 11.5 tons — a 35% spread in weight and about $150 in cost. Guess the stone and you either pay for rock you do not need or come up short with the machine already booked.
The confidence column is there because we would rather show you the uncertainty than hide it. Most of these figures are corroborated — several independent supplier tables agree. One is marked low, meaning published values disagree enough that you should treat the figure as a starting point rather than a number to order from — dense crushed limestone in particular varies a lot by quarry. Whichever row you use, the supplier's own tons-per-yard figure beats ours every time — they weigh their product; we are working from published averages.
How much ground does a ton of gravel cover?
At the default 1.4 tons per cubic yard, coverage per ton is 324 ÷ (depth × density). Tons in the last column include the standard 10% allowance and round up to the half-ton, the way suppliers sell.
| Depth | Sq ft per ton | Sq ft per cubic yard | Tons per 100 ft² | Typical use |
|---|---|---|---|---|
| 2″ | 116 ft² | 162 ft² | 1 t | Decorative beds, refreshing a path |
| 3″ | 77 ft² | 108 ft² | 1.5 t | Walkways, patio sub-base, dog runs |
| 4″ (default) | 58 ft² | 81 ft² | 2 t | Topping up an existing driveway |
| 6″ | 39 ft² | 54 ft² | 3 t | Paver base, drainage trench |
| 8″ | 29 ft² | 41 ft² | 4 t | New drive over soft ground, heavy vehicles |
One ton is less material than it sounds: 58 square feet at 4 inches, or roughly a 7½ ft square — about the footprint of one parked car. That is why a driveway that "only needs a few tons" turns out to be a ten-ton order once you actually measure it.
Common driveway sizes at 4 inches
These are surfacing quantities — the amount to spread over a drive that already has a base. Cost is $50 per ton, before delivery.
| Driveway | Area | Cubic yards | Tons to order | Est. stone cost | Typical use |
|---|---|---|---|---|---|
| 10 × 20 ft | 200 ft² | 2.47 | 4 t | $200 | One car, parking pad |
| 12 × 24 ft | 288 ft² | 3.56 | 5.5 t | $275 | Two cars side by side, short |
| 12 × 40 ft | 480 ft² | 5.93 | 9.5 t | $475 | Single-width run to a detached garage |
| 16 × 40 ft | 640 ft² | 7.9 | 12.5 t | $625 | Double-width run |
| 20 × 50 ft | 1,000 ft² | 12.35 | 19.5 t | $975 | Wide drive with a turnaround |
Delivery is charged separately and usually by the load, so the cost per ton drops sharply once you fill a truck. A tandem-axle dump typically carries somewhere around 12 to 15 tons; if your order is close to a full load, rounding up is often cheaper per ton than a second trip later. Ask for the delivered total, not the per-ton rate.
A new driveway is three layers, not one
The 4 inch figure above is for topping up. Build a driveway from bare soil with a single 4 inch course of stone and it will rut and disappear into the subgrade within a season. A driveway built to last is 11 inches of stone in graded layers, each compacted before the next goes down. For the same 12 × 40 ft drive:
| Course | Product | Depth | Tons | Est. cost | What it does |
|---|---|---|---|---|---|
| Base course | #2 / #3 large angular stone (2–3 in) | 4″ | 8.5 t | $425 | Bridges soft subgrade and carries the load. Big and angular so it locks together instead of sinking into mud. |
| Middle course | Crusher run / road base | 4″ | 10.5 t | $525 | Graded sizes plus stone dust. Fills the voids in the base and compacts to a near-solid platform. |
| Top course | #57 crushed stone (¾ in clean) | 3″ | 7 t | $350 | The surface you see and drive on. Sheds water, easy to regrade and top up every few years. |
| Total | — | 11″ | 26 t | $1,300 | A drive that survives loaded trucks and freeze-thaw |
That is about 2.7× the cost of the single-course number people budget from — $1,300 against $475. It is the single biggest reason gravel drive projects blow their budget. Eight inches total is the minimum on firm, well-drained ground; twelve is right over clay or anywhere with a real frost cycle. Lay geotextile fabric under the base course if the subgrade is soft — it stops the stone punching down into the soil and typically pays for itself in stone you do not have to buy twice. The full sequence is in how much gravel for a driveway.
Compaction: how much extra to order
Loose stone off the truck occupies more space than the same stone once it is rolled. How much more depends entirely on what you bought. Crusher run and other graded products with fines compact hard — the fines migrate into the voids and the layer loses noticeable thickness. Clean single-size stone like #57 or pea gravel has nowhere to go, so it barely settles at all.
Our default allowance is 10%, which covers spillage, uneven ground and mild settlement. Building a compacted base, push it to 15–20%. Here is what that does to the same 480 ft² order:
| Allowance | Tons to order | Est. cost | When to use it |
|---|---|---|---|
| 0% | 8.5 t | $425 | Bare geometry — useful as a sanity check, never as an order |
| 10% (default) | 9.5 t | $475 | Loose decorative stone on prepared ground |
| 15% | 10 t | $500 | Surfacing over an uneven existing drive |
| 20% | 10 t | $500 | Compacted base course, soft or rutted subgrade |
Notice that on this job the 15% and 20% rows land on the same order. Because aggregate rounds up to the half-ton, the whole span from no allowance to a generous one is just 1.5 tons — $75. Running short costs far more than that: a second delivery carries another full trip fee, and a base course finished on a different day never knits together as well as one laid and rolled in a single pass. Order the higher figure.
Why ordering by weight goes wrong
You need a volume. You are sold a weight. Every problem in aggregate ordering lives in that gap.
Moisture. Stone soaks up water, and you pay for it on the scale. A load taken from an uncovered stockpile after two days of rain delivers measurably less rock per ton than the same product taken from under cover in August. Nobody is cheating you — the ticket is honest — but the driveway still comes up short.
Gradation and quarry. Density depends on how the sizes pack together and on the parent rock. A well-graded product with fines packs tighter, and therefore weighs more per yard, than the same nominal size washed clean. Two suppliers can label a product identically and be 10% apart.
Here is the size of the error. Plan at 1.4 t/yd³ and one ton should cover 58 ft² at 4″. If what turns up is closer to 1.6 t/yd³, that ton covers only 51 ft² — you are 13% short. On the 12 × 40 ft drive above, 9.5 tons that should have covered 550 ft² covers 481 ft² instead, leaving about 69 ft² bare.
The fix takes one phone call: give the supplier your cubic yards and the depth, and ask them to convert. They know what their stone weighs today. The conversion itself is explained in cubic yards to tons and bags.
Which stone should you actually buy?
Stone is specified by the job it has to do, not by looks. Pick the row that matches the job, then select the matching density in the calculator above.
| Stone | Size | Density to select | What it is for |
|---|---|---|---|
| #57 stone | ¾ in, angular, washed clean of fines | Crushed stone (generic) (1.4) | Driveway top course, under slabs, French drains, backfill. Drains freely because there are no fines to clog it — and for the same reason it never locks up, so it stays loose underfoot. |
| Crusher run (¾ in minus, QP, road base) | ¾ in down to stone dust | Crusher run / road base (1.6) | Anything that has to stay put: driveway base, paver and shed bases, farm tracks. The fines act as a binder, so compacted crusher run behaves almost like a soft pavement. |
| Pea gravel | 3⁄8 in, rounded, smooth | Crushed stone (generic) (1.4) | Walkways, patios, play areas, dog runs, decorative beds. Rounded stone rolls rather than locks, so it needs solid edging and is a poor choice on a slope or under turning tires. |
| #2 / #3 stone | 1½–2½ in, angular | Large rock (2–6 in) (1.25) | The first lift on a new driveway or over soft, wet ground. Too coarse to walk or drive on directly — it is a foundation, not a surface. |
| Crushed limestone / DG fines | Graded fines and screenings | Crushed limestone (dense) (1.69) | Garden paths and patios where you want a firm, walkable surface. Packs hard, but tracks indoors and turns to paste in standing water without a stabilizer. |
The one mistake to avoid: using clean, rounded stone where you needed something that locks. Pea gravel on a driveway looks wonderful for a fortnight, then migrates into the lawn under every turning wheel and leaves ruts you have to rake weekly. If vehicles will drive on it, you want angular stone, and if it has to stay in place you want fines in the mix. Decorative rounded stone belongs on paths, in beds, and anywhere feet — not tires — are the only traffic.
Getting your measurements right
Measure the driveway at its widest, including the flare where it meets the road and any parking spur, and add them as separate rectangles. Curved drives are best handled by measuring the width at several points, averaging, and multiplying by the centreline length. If you are replacing a surface rather than building new, probe with a screwdriver in a few spots first — you may find 3 inches of usable base already there, which changes the order more than any refinement of the arithmetic. Then run the numbers above, and cross-check against the mulch calculator if the same project involves beds, or the concrete calculator if you are pouring an apron at the road. Every constant we use is listed in how we calculate, and there is more background in the guides.
Last updated: 2026-08-20.
Densities per Inch Calculator and aggregate-supplier tables;
confidence levels are shown in the table above because published figures
disagree. Prices are US national-average
estimates (as of June 2026), not live quotes —
stone rates vary by region, quarry distance and season, and delivery is charged
separately. Layer depths and compaction allowances follow standard residential
practice. Planning estimates only — see terms.