Gravel & Aggregate Calculator

Your inputs

A rectangular path, patio, or pad

What are you covering?

A driveway is the same rectangle as a patio. It is listed separately because it needs two to three times the depth.

Length

The long side of the area, measured inside the edging.

Width

The short side. Split an irregular area into rectangles and add the cubic feet.

Finished depth

Two to three inches for a walkway or a decorative area; four inches for a patio base under pavers.

Material

The density is what turns your cubic feet into the tons a quarry bills for. These are typical figures; a supplier who tells you theirs has given you a better one.

Compaction allowance

Aggregate arrives loose and finishes compacted. A plate compactor takes roughly a fifth of the loose volume out of a lift, so ordering for the finished depth alone leaves the job thin. Set it to zero for decorative stone that is never compacted.

Price per ton

The quarry’s price for the material alone. Delivery, minimum-load fees, and fuel surcharges are quoted separately and are not in this estimate.

Your inputs are calculated locally and are not stored.

Aggregate to order3.00 tons

60.00 cu ft — 2.22 cu yd — at 100 lb per cubic foot weighs 6,000 lb, or 2.72 metric tonnes, and costs about $135.00 in material.

Area to cover: 200.00 sq ft
Finished layer at 3 in: 50.00 cu ft
Compaction allowance (20%): 10.00 cu ft
Order this much: 60.00 cu ft
In cubic yards: 2.22 cu yd
Weight: 6,000 lb
US short tons: 3.00 tons
Metric tonnes: 2.72 t
Density used: 100 lb/cu ft
Material cost: $135.00

The same 60.00 cu ft in every material
Material	Density	Short tons
Topsoil	76 lb/cu ft	2.28
Pea gravel	96 lb/cu ft	2.88
Crushed stone, ¾ in	100 lb/cu ft	3.00
Sand, dry	100 lb/cu ft	3.00
Crushed stone dust	105 lb/cu ft	3.15
River rock	105 lb/cu ft	3.15
Decomposed granite	110 lb/cu ft	3.30
Road base	120 lb/cu ft	3.60
Sand, wet	120 lb/cu ft	3.60

Order for the compacted depth plus the compaction allowance. The 3 inch layer above is what you want when the compactor has finished; the 60.00 cu ft is what has to arrive loose to get there.
Published densities are midpoints. Moisture and grading move them by twenty percent or more, so a supplier’s tonnage and this one will rarely agree exactly — order by volume and let the yard convert, or ask them for their density and enter it here.
The cost is material only, at $45.00 a short ton of 2,000 lb. Delivery, minimum-load charges, and any spreading are extra.

Formula & methodology

From a hole in the ground to a ticket in tons

Three steps, and only the last one is interesting. Take the area and the finished depth to get the compacted volume. Add the compaction allowance to get the loose volume that has to be delivered. Then multiply by a density to reach weight — which is the step that turns an exact geometric answer into an estimate, because density is the one number here that nobody has measured.

V_compacted= A × (D ÷ 12)  •  V_loose = V_compacted× (1 + c)  •  tons = V_loose× ρ ÷ 2000  •  t = lb × 0.45359237 ÷ 1000

A, D: Area in square feet and the finished depth in inches, hence ÷ 12 to reach feet
c: Compaction allowance, about 0.20 for a granular base — the volume the compactor squeezes out
ρ: Loose density in pounds per cubic foot, from the material list or from your supplier
÷ 2000: Pounds to US short tons. The metric tonne uses the exact 0.45359237 kg definition of the pound instead

Weighing the loose volume at the loose density is not double counting, which is worth spelling out because it looks like it might be. Compaction moves material closer together; it does not create or destroy any. Twelve cubic feet of loose stone at 100 pounds per cubic foot and ten cubic feet of the same stone compacted to 120 both weigh 1,200 pounds. The quarry weighs the truck, so the loose figure is the one on the ticket.

Worked example

A 20 × 10 patio base, then a driveway

The pad is 20 × 10 = 200 square feet. Three inches is 0.25 feet, so the finished layer is 50 cubic feet. A twenty percent compaction allowance adds 10 cubic feet, so 60 cubic feet — 2.22 cubic yards — has to arrive loose. At 100 pounds per cubic foot for ¾ inch crushed stone that is 6,000 pounds, or exactly 3.00 short tons and 2.72 metric tonnes. At $45 a ton the material is about $135, before delivery.

Now the driveway, where the numbers stop being friendly. A 40 by 12 foot run at six inches is 480 square feet × 0.5 feet = 240 cubic feet compacted, and 288 cubic feet — 10.67 cubic yards — loose. In road base at 120 pounds per cubic foot that is 34,560 pounds, or 17.28 short tons. At $30 a ton the material comes to roughly $518, and it is arriving on a truck with an axle limit, which is its own conversation with the supplier.

Change one input on that driveway and watch what happens: switch from road base to pea gravel and the same 288 cubic feet is 13.82 tons rather than 17.28. Identical hole, twenty percent less weight, twenty percent less invoice. That gap is the reason the material and its density are an input rather than a constant.

The line most tools omit

Order for the compacted depth, plus the compaction allowance

This is the single most useful sentence on the page, and most gravel calculators do not contain it. Aggregate is delivered loose and full of voids. Compacting it — with a plate compactor, a roller, or simply months of vehicle traffic — drives those voids out and the layer loses roughly a fifth of its volume. A six inch lift spread loose finishes at about five.

So the depth you design is not the depth you order. Work out the finished, compacted volume from your dimensions, then add the allowance on top to find the loose volume the truck has to bring. Skip that step and the driveway is twenty percent thin, which does not show up until the first winter, by which point fixing it means another delivery and another day.

Twenty percent is the usual figure for a well-graded granular base and is the default here. Uniform decorative stone that is never compacted needs no allowance at all — set it to zero. Deep lifts need to be placed and compacted in stages of four to six inches, because a compactor densifies from the top down and cannot reach the bottom of a twelve inch layer.

Weight versus volume

Why your tonnage and the supplier’s will not agree

Every density in the material list is a midpoint. The real figure for the pile being loaded into your truck depends on moisture and on grading, and both move it further than people expect. Sand picks up twenty pounds per cubic foot between a dry pile and one that has been rained on — that alone is a twenty percent swing in the weight of an identical volume. Grading does something similar: uniformly sized stone leaves large voids between the pieces, while a well-graded mix has fines that fill them, and the second weighs meaningfully more per cubic foot than the first.

The practical consequence is that a calculation done in volume and a quote written in weight will rarely land on the same number, and neither party is wrong. Two ways out, in order of preference: order in cubic yards and let the yard do the conversion on their own scale, or ask what their material actually weighs per cubic foot and enter it as a custom density here. A supplier who knows their product will answer that question without hesitating.

Treat the tonnage on this page as accurate to about ten percent — good enough to plan a delivery and budget a job, not good enough to argue over an invoice.

Depth guide

How deep, by what it has to carry

Two to three inches — a walkway, a decorative bed, or a stone border. Enough to cover the ground and stay put; nothing structural is being asked of it.
Four inches — a patio base under pavers or flagstone, over a compacted subgrade. This is the layer that keeps the surface flat, so compact it properly and screed it level.
Six to eight inches — a driveway that will carry a car, over a prepared and compacted sub-base, placed in two or three lifts. Under four inches and vehicle loads punch through: ruts first, then potholes, usually inside a year.
More than eight inches — soft, wet, or clay subgrades, heavier vehicles, or anywhere frost heave is a factor. At this point the sub-base and the drainage matter more than the stone, and it is worth asking someone local rather than a calculator.

Assumptions

What this calculator assumes

Depth is uniform and the subgrade is flat. Real excavations are deeper in places, and a driveway that has already rutted needs more material than its nominal depth implies.
The published densities are typical loose figures in pounds per cubic foot, not standards. Moisture and grading move them by twenty percent or more — if the supplier will tell you theirs, use it instead.
Tons are US short tons of 2,000 pounds. Metric tonnes use the exact 0.45359237 kilogram definition of the pound. The British long ton of 2,240 pounds is not offered, because construction aggregate is not priced in it.
The compaction allowance is applied to the whole volume as a single percentage. Twenty percent suits a well-graded granular base; uniform decorative stone that is never compacted needs none.
The cost estimate covers material only, at the price per ton you enter. Delivery, minimum-load charges, fuel surcharges, and spreading are quoted separately and can rival the material cost on a small order.
Nothing here addresses geotextile fabric, edge restraint, drainage, sub-base design, or whether your subgrade will carry the load. Those are engineering questions, and on a driveway they matter more than the arithmetic on this page.

Common questions

Gravel calculator FAQ

How many tons of gravel are in a cubic yard?

About 1.35 short tons for ¾ inch crushed stone. The arithmetic is 27 cubic feet to the cubic yard, multiplied by the density in pounds per cubic foot, divided by the 2,000 pounds in a short ton: 27 × 100 ÷ 2,000 = 1.35. Change the material and the answer changes with it — pea gravel at 96 lb/cu ft gives 1.30 tons, road base and wet sand at 120 lb/cu ft give 1.62, topsoil at 76 gives 1.03. There is no single conversion between yards and tons, which is exactly why a density has to be chosen before the question can be answered at all.

Why does my supplier quote a different tonnage than this calculator?

Because they are using a different density, and both of you are probably right. Published densities are midpoints of a range that moisture and grading widen by twenty percent or more: the same crushed stone weighs noticeably more after a week of rain than it does off a dry pile, and uniformly sized stone leaves more air between the pieces than a well-graded mix that packs together. Two ways to make this stop being a problem. Order by volume in cubic yards and let the yard convert to weight on their own scale, or ask what the pile you are being loaded from actually weighs per cubic foot and enter that here.

How deep should gravel be for a driveway?

Six to eight inches of compacted aggregate over a prepared, compacted sub-base for a driveway that will carry a car — often placed as two or three lifts, each compacted separately, because a compactor cannot densify a deep layer from the top. Anything under four inches will rut and pothole within a season under vehicle loads. On soft or clay soils the sub-base matters more than the depth of the gravel; without a stable base, the stone simply migrates into the subgrade and disappears. Walkways and decorative areas are a different problem entirely and only need two to three inches.

What does compaction do to the amount I need to order?

It adds roughly twenty percent. Aggregate arrives loose and full of voids, and a plate compactor or roller drives those voids out — a lift that measures six inches loose finishes at around five. Order for the compacted depth alone and the finished job is a fifth thinner than you designed. The fix is simple and this calculator does it by default: work out the finished, compacted volume from the geometry, then add the compaction allowance on top to get the loose volume that has to be delivered. Twenty percent is the usual working figure for a granular base; it varies with grading and with how hard the material is worked, so it is shown as its own line you can change.

How much gravel do I need for a 20 by 10 foot patio base?

About 3 short tons of ¾ inch crushed stone at a 3 inch base. The area is 200 square feet, and 3 inches is 0.25 feet, so the finished layer is 50 cubic feet. Adding a twenty percent compaction allowance gives 60 cubic feet — 2.22 cubic yards — to order loose. At 100 pounds per cubic foot that is 6,000 pounds, which is exactly 3.00 short tons or 2.72 metric tonnes. At $45 a ton the material comes to roughly $135, before delivery.

Should I order gravel by the yard or by the ton?

By the yard if you can, because volume is what you measured. Your calculation starts from a length, a width, and a depth, and every one of those is a distance — converting to weight requires a density that neither you nor the calculator can measure at the pile. Order in cubic yards and any error in the density estimate stays out of the transaction. If the supplier only sells by weight, ask for their conversion factor rather than using a table, and confirm whether their price is per short ton of 2,000 pounds or per metric tonne of 1,000 kilograms — the tonne is about ten percent heavier, which is ten percent of the invoice.

What is the difference between a short ton, a long ton, and a tonne?

A US short ton is 2,000 pounds, and it is the unit almost every American quarry ticket is written in. A metric tonne is 1,000 kilograms, which works out to about 2,204.6 pounds — roughly ten percent heavier. A British long ton is 2,240 pounds and rarely appears in construction material pricing today. This calculator reports short tons and metric tonnes side by side so a quote in either unit can be checked without a second conversion.

Primary sources

Sources and review notes

The geometry and the unit conversions here are exact. The densities are not: they are typical values for typical material at typical moisture, and they are the largest source of uncertainty in any tonnage on this page. So is the twenty percent compaction allowance, which is a working figure rather than a measured one. Confirm both with the yard before a large order.