Guide
Gravel by the Ton vs. the Cubic Yard: How Much to Order
At the density the JoistCalc gravel calculator uses for gravel and paver base, 105 pounds per cubic foot, one cubic yard weighs about 1.42 tons, so tons are roughly cubic yards × 1.42. A 10 × 20 ft driveway base 6 inches deep is 100 cubic feet: 3.7 cubic yards and 5.25 tons before waste, or 4.07 cubic yards and 5.78 tons to order once the calculator's default 10% waste factor is added. The rest of this guide shows where those numbers come from, how they change with the material, and how much a patio base, a walkway or a drain trench takes.
Why you measure in yards but buy in tons
The hole you are filling is a volume: length times width times depth. Many quarries and landscape yards, though, price aggregate by weight. Getting from one to the other takes a third number, the bulk density of the material, which is how many pounds one cubic foot of it weighs.
Density is not a fixed property of "gravel." It depends on the kind of rock, the size and shape of the pieces, how much fine material fills the gaps between them, and how much water the pile is holding. Water has weight, so a yard of material that has been rained on weighs more than the same yard dry, and when you buy by the ton you pay for that water. That is why the same cubic yard can be quoted at different tonnages by two suppliers, and why the calculator's own field note calls its densities approximate.
Two unit details matter. A cubic yard is 3 × 3 × 3 feet, which is 27 cubic feet. A ton in a US quote is normally the short ton of 2,000 lb, which is what the calculator uses. A metric tonne is 1,000 kg, about 1.1 short tons, so a quote in tonnes is roughly 10% heavier per unit than one in US tons. If you switch the calculator to Metric, its tonnage is shown in metric tonnes.
Tons per cubic yard for each material in the calculator
These are the five densities built into the calculator's Material list, converted to tons per cubic yard. They are planning values, not test results for any particular quarry's product. To reproduce any row, enter Length 9 ft, Width 9 ft, Depth 4 in (exactly 27 cubic feet, one cubic yard), set Waste factor to 0 and pick the material: the tonnage shown is the figure in the last column.
| Material option | Density | Weight of 1 yd³ | Tons per cubic yard |
|---|---|---|---|
| Gravel / paver base | 105 lb/ft³ | 2,835 lb | 1.42 |
| Crushed stone | 100 lb/ft³ | 2,700 lb | 1.35 |
| Sand | 100 lb/ft³ | 2,700 lb | 1.35 |
| Decorative / river rock | 95 lb/ft³ | 2,565 lb | 1.28 |
| Topsoil | 76 lb/ft³ | 2,052 lb | 1.03 |
The spread is wider than it looks. For the same 10 × 20 ft area at 6 in with 10% waste, the order volume stays at 4.07 cubic yards whatever you pick, but the tonnage runs from 5.23 tons for river rock to 5.5 for crushed stone and 5.78 for paver base. If your supplier publishes a density or a tons-per-yard figure for the exact product, use theirs: divide their tons per yard by 27 and multiply by 2,000 to get pounds per cubic foot, which is a quick way to compare a quote against the table above.
Worked example: how many tons of gravel for a 10 × 20 driveway
A 10 ft × 20 ft parking pad with a 6 in base, using the calculator's Gravel / paver base option (105 lb/ft³) and its default 10% waste factor, in Imperial mode:
- Area = 10 × 20 = 200 sq ft
- Depth = 6 ÷ 12 = 0.5 ft
- Volume = 200 × 0.5 = 100 cu ft, which is 100 ÷ 27 = 3.7 cubic yards
- Order volume = (100 × 1.10) ÷ 27 = 4.07 cubic yards
- Weight = 100 × 105 × 1.10 = 11,550 lb = 5.78 tons
- Weight without waste = 10,500 lb = 5.25 tons
Enter Length 20, Width 10, Depth 6 and the calculator shows 5.78 tons, a volume of 100 ft³, an order volume of 4.07 yd³ and 5.25 tons without waste. The calculator opens with this same driveway at 4 in instead of 6, and pressing Calculate on its defaults gives 3.85 tons and 2.72 cubic yards: a third less material for a third less depth. That difference is why the depth decision, covered below, matters more than any rounding in the density.
Common jobs, run through the calculator
Every row below was computed with the calculator's own formula, in Imperial mode, with the default 10% waste factor. Type the inputs shown and you get the same results. The depths are the published minimums discussed in the next section, except the drain trench, whose size is only an example.
| Job | Inputs (L × W × depth, material) | Volume | Order volume | Tons, waste included |
|---|---|---|---|---|
| Paver driveway base, 1 car | 20 × 10 ft × 6 in, gravel / paver base | 100 ft³ | 4.07 yd³ | 5.78 |
| Paver driveway base, long | 50 × 12 ft × 6 in, gravel / paver base | 300 ft³ | 12.22 yd³ | 17.33 |
| Patio base, 12 × 12 | 12 × 12 ft × 4 in, gravel / paver base | 48 ft³ | 1.96 yd³ | 2.77 |
| Patio bedding sand, 12 × 12 | 12 × 12 ft × 1 in, sand | 12 ft³ | 0.49 yd³ | 0.66 |
| Paver walkway base | 30 × 3 ft × 4 in, gravel / paver base | 30 ft³ | 1.22 yd³ | 1.73 |
| Drain trench (example size) | 50 × 1 ft × 12 in, crushed stone | 50 ft³ | 2.04 yd³ | 2.75 |
Two cautions on this table. First, the calculator counts the full trench, so for a drain with a pipe in it the stone figure is a little high by the volume the pipe takes up, which errs on the side of having enough. Second, the base depths are compacted minimums. Material with fines settles when it is compacted, so the loose depth you spread has to be greater than the finished depth; ask your supplier how much their product compacts and enter the loose depth, rather than adding it to the waste factor and losing track of both.
How much gravel for a patio base, walkway or driveway: the depth
For segmental paver work, the Concrete Masonry & Hardscapes Association (CMHA) publishes minimum base thicknesses in its tech note on constructing interlocking concrete pavements. They are minimums, stated for well-drained soil, and measured after compaction. The same note says colder climates and continually wet or weak soils need thicker bases.
| Use | Minimum | Condition | Source |
|---|---|---|---|
| Sidewalks, patios, pedestrian areas | 4 in base | After compaction, well-drained soil | CMHA PAV-TEC-002 |
| Residential driveway (pavers) | 6 in base | Well-drained soil | CMHA PAV-TEC-002 |
| Bedding sand under pavers | 1 in | Uncompacted nominal thickness, screeded | CMHA PAV-TEC-002 |
| Cold climate, wet or weak soil | Thicker | No single figure given; local practice or an engineer decides | CMHA PAV-TEC-002 |
A plain gravel driveway with no pavers on top is not covered by that note, and there is no single national standard for one. The paver-driveway minimum is still a useful floor, since the base under a gravel surface carries the same cars. Where your soil is soft, wet, clay or subject to frost, plan on more depth than these minimums and check what local contractors or your county use.
Where gravel orders go wrong
- Treating tons and yards as the same number. At 105 lb/ft³ a yard is 1.42 tons, at 76 it is 1.03. Ask which unit the price is in, and if it is by weight, what density the supplier is assuming.
- Mixing up US tons and metric tonnes. A tonne is about 1.1 US tons. A quote in tonnes and a quote in tons for the same pile will not match, and neither is wrong.
- Ordering the compacted depth as if it were loose. The minimums above are measured after compaction. Spread only the compacted depth and the finished base comes out thin.
- Compacting it all in one pass. CMHA's note calls for compacting the base in 4 to 6 in lifts with a 7,000 lbf reversible plate compactor, and thinner lifts with a smaller 5,000 lbf machine. With the smaller machine, a 6 in driveway base needs at least two lifts.
- Measuring depth from the finished surface. The depth you enter is the thickness of the gravel layer. On a paver patio the 4 in of base sits below 1 in of bedding sand and the pavers themselves, so the excavation is deeper than the base.
- Skipping the subgrade question. CMHA lists geotextile as an option where soil stays saturated part of the year, where there is freeze and thaw, or over clay and moist silty soil. Those are also the conditions where the minimum depth is not enough.
- Forgetting the second material. A paver patio is two orders: base and bedding sand. The 12 × 12 patio above is 2.77 tons of base plus 0.66 tons of sand.
Run your own numbers
The JoistCalc gravel calculator does every step above at once: enter length, width and depth, pick the material and waste factor, and it returns tons with waste, raw volume, order volume in cubic yards and tons without waste side by side, so a quote in either unit can be checked against the same job. It also switches to metric if your supplier works in meters and tonnes.
Where these numbers come from
The densities and every computed figure come from the calculator's own values and formula. The unit definitions and the base-depth minimums come from the sources below.
- CMHA Tech Note PAV-TEC-002, Construction of Interlocking Concrete Pavements — Minimum base thickness for patios and walkways (4 in) and residential driveways (6 in), 1 in bedding sand, compaction lifts and when to use geotextile.
- NIST Guide to the SI, Appendix B.9 — Conversion factors for the short ton (2,000 lb), the metric tonne and the cubic yard.
- ASTM D448 — Standard classification for sizes of aggregate, the source of size numbers such as No. 57 stone that appear on quarry tickets.
How many tons are in a cubic yard of gravel?
About 1.42 tons at the 105 lb/ft³ the calculator uses for gravel and paver base, and 1.35 tons for crushed stone at 100 lb/ft³. The exact figure depends on the product and its moisture, so use your supplier's number if they give one.
How many tons of gravel do I need for a 10x20 driveway?
At 6 inches deep with gravel or paver base and 10% waste, 5.78 tons (4.07 cubic yards). At 4 inches deep, 3.85 tons (2.72 cubic yards). Without any waste allowance the 6-inch figure is 5.25 tons.
How much gravel do I need for a 12x12 patio base?
At the 4-inch compacted minimum for patios, 2.77 tons (1.96 cubic yards) of paver base with 10% waste, plus 0.66 tons of bedding sand for a 1-inch layer. Spread the base loose a little deeper than 4 inches so it finishes at 4 after compaction.
How do I convert cubic yards of gravel to tons?
Multiply cubic yards by the density in lb/ft³, then by 27, then divide by 2,000. At 105 lb/ft³ that is cubic yards × 1.42; at 100 lb/ft³ it is cubic yards × 1.35.