What one ton actually covers
Every coverage figure starts from the same volume and then divides by density. One ton of gravel is 27 ÷ density cubic feet, so the heavier the stone, the less space a ton fills. Stack that against depth and you get the table below — the same four materials this site's gravel calculator uses.
| Material | Tons / cu yd | 2 in deep | 3 in deep | 4 in deep | 6 in deep |
|---|---|---|---|---|---|
| Pea gravel (3/8 in) | 1.40 | 116 sq ft | 77 sq ft | 58 sq ft | 39 sq ft |
| Crushed stone #57 | 1.45 | 112 sq ft | 74 sq ft | 56 sq ft | 37 sq ft |
| River rock | 1.35 | 120 sq ft | 80 sq ft | 60 sq ft | 40 sq ft |
| Crusher run (dense grade) | 1.50 | 108 sq ft | 72 sq ft | 54 sq ft | 36 sq ft |
Why the numbers online disagree
The most repeated figure on the internet is that one ton covers about 100 square feet at 2 inches. Work backwards and that implies a density of 1.62 tons per cubic yard — heavier than any of the four materials above, and heavier than almost any aggregate you can buy. It is a round number that got copied.
The 108-square-foot figure you also see is a real calculation: it is exactly what crusher run at 1.50 tons per cubic yard produces at the same 2 inches. Both numbers are in circulation, neither is labelled with the material it assumes, and the gap between them is 8 percent of your order. On a 44-ton driveway that is three and a half tons of guesswork.
The fix is to stop asking how much a ton covers and start asking what your material weighs. Density is printed on the supplier's product sheet, and once you have it the coverage follows from one division.
A driveway is three layers, not one depth
This is where most driveway answers go wrong. A single depth number like “4 to 6 inches” is describing either the base or the surface, and the sources never say which — which is why published totals range from 4 inches to 18. Build it as two materials in two jobs and the confusion disappears:
| Traffic | Load | Build-up | Total depth | Tons / 100 sq ft |
|---|---|---|---|---|
| Light | Cars and an occasional trailer | 4 in crusher run + 2 in #57 | 6 in | 2.8 |
| Residential | Cars plus delivery trucks | 6 in crusher run + 2 in #57 | 8 in | 3.8 |
| Heavy | RV, dump truck, year-round use | 8 in crusher run + 2 in #57 | 10 in | 4.7 |
The base carries the load; the surface sheds water and stops tires picking stone up. Crusher run is the base because its stone dust compacts into a plate. Washed #57 is the surface because it drains. Using #57 for both leaves you with a base that never locks together, and using crusher run on top puts dust straight into your wheel wells.
Tonnage by driveway size
Totals for both layers together, at the depths above. These are compacted figures — the material you order to fill the volume you just calculated.
| Driveway | Area | Light (6 in) | Residential (8 in) | Heavy (10 in) |
|---|---|---|---|---|
| 10 × 20 ft | 200 sq ft | 5.6 t | 7.5 t | 9.3 t |
| 10 × 40 ft | 400 sq ft | 11.2 t | 14.9 t | 18.6 t |
| 12 × 50 ft | 600 sq ft | 16.7 t | 22.3 t | 27.8 t |
| 12 × 100 ft | 1,200 sq ft | 33.4 t | 44.5 t | 55.6 t |
These totals cost the full depth at crusher run's 1.5 tons per cubic yard. Pricing the top layer at #57's 1.45 instead moves the 12 × 100 ft figure by well under a percent, always downward — so the table rounds toward ordering slightly more rather than less.
Read the middle column as the default. A 12 × 100 foot driveway built to 8 inches is 44.5 tons — which is three truckloads, not one, and the reason gravel driveways get built in stages with the surface layer added a season later after the base has settled.
Ordering and spreading
- Compact in lifts. Spread and compact 2 to 4 inches at a time. Dumping the full 8 inches and running over it once leaves the bottom loose, and loose base is where ruts start.
- Order by the ton, not the yard. Yards are a volume and tons are a weight, and the conversion moves with moisture. Suppliers sell by weight because that is what the truck scale reads.
- Crown it slightly. 1 to 2 percent fall from the centreline to the edges costs nothing and is the difference between a driveway that drains and one that grows puddles.
- Mind the edge. Gravel without an edge restraint creeps outward under tires. In the first year of a new driveway, plan on topping up the shoulders.
Run your own dimensions through the gravel calculator — that link opens on the 12 × 100 ft residential build from the totals table, 8 inches of crusher run, which is where the 44.5 tons come from. It takes the four material types above, returns cubic yards, tons, and a 50 lb bag count from the same volume, and lets you price each layer separately.