Understanding your result
The headline is the weight to order, in tons (or metric tonnes). Quarries and landscape yards weigh stone on a scale as it is loaded, so this is the number they want. The line beneath gives the volume, in case your supplier sells by the cubic yard instead, and the number of bags for small jobs.
The bulk order figure is rounded up to the next quarter ton. Loose stone is cheap compared with the cost of a second delivery, so a little over is the right side to be on.
Density used shows the weight per cubic yard the calculator assumed for your stone. It is the single biggest source of error in any gravel estimate. Two loads of “three-quarter inch crushed stone” from two different quarries can differ by 10% or more.
If you checked the compaction box, the table shows the extra volume added so that the layer still measures the depth you asked for after it has been packed down.
How we calculate this
In metric, the volume is in cubic meters, the density in kilograms per cubic meter, and the result in tonnes of 1,000 kilograms.
The compaction factor is applied before the extra allowance. Compaction is a predictable loss of volume when angular stone with fines is packed with a plate compactor. The extra allowance covers the unpredictable part: uneven ground, stone trodden into the soil, and spillage.
The assumptions behind the numbers
| Material | Density used, lb per cu yd | Tons per cu yd | kg per m³ |
|---|---|---|---|
| Crushed stone or gravel | 2,700 | 1.35 | 1,600 |
| Pea gravel | 2,600 | 1.30 | 1,540 |
| River rock | 2,600 | 1.30 | 1,540 |
| Decomposed granite | 2,900 | 1.45 | 1,720 |
| Crusher run / road base | 2,800 | 1.40 | 1,660 |
| Sand | 2,700 | 1.35 | 1,600 |
| Lava rock | 1,300 | 0.65 | 770 |
These are loose, as-delivered densities in the middle of the usual range. Expect your supplier’s figure to be within 10 to 15% either way. Other assumptions:
| Assumption | Value used | Why |
|---|---|---|
| Compaction | 15% extra volume when checked | Typical loss when crusher run or road base is plate-compacted |
| Extra allowance | 5% unless you change it | Uneven ground and stone lost into the soil |
| Bulk rounding | Up to the next 0.25 ton | Loose stone is weighed out, and a small surplus is cheap |
| Bag size | 50 lb (20 kg) unless you change it | The standard retail bag, about 0.5 cu ft |
Assumptions last reviewed October 3, 2026.
Two worked examples
A pea gravel path
A garden path is 40 feet long and 3 feet wide, edged and lined with fabric. It will be filled with 2 inches of pea gravel.
- Area: 40 × 3 = 120 sq ft
- Volume: 120 × 2 ÷ 12 = 20 cu ft
- With 5% extra: 21 cu ft, which is 0.78 cu yd
- Weight: 0.78 × 2,600 = 2,022 lb, or 1.01 tons
- Bulk order: 1.25 tons
- In 50 lb bags: 2,022 ÷ 50 = 40.4, so 41 bags
Say bags cost $5.50 each and loose pea gravel is $45 a ton with a $75 delivery charge. Forty-one bags come to $225.50. A ton and a quarter delivered comes to $131.25. Even with delivery, the loose load saves $94, and nobody has to carry 41 bags from the car.
A driveway base
A new driveway is 50 feet by 10 feet. The base layer is 4 inches of crusher run, compacted.
- Area: 50 × 10 = 500 sq ft
- Volume: 500 × 4 ÷ 12 = 166.7 cu ft
- With 15% for compaction: 191.7 cu ft
- With 5% extra: 201.3 cu ft, which is 7.45 cu yd
- Weight: 7.45 × 2,800 = 20,870 lb, or 10.4 tons
- Bulk order: 10.5 tons
Without the compaction allowance the order would have been about 9.1 tons, and the finished base would have come out at roughly three and a half inches instead of four. On a driveway, that missing half inch is the difference between a base that holds and one that ruts.
Common mistakes
- Ordering by volume from a supplier who sells by weight. Ask how they sell before you call, and have both numbers ready.
- Forgetting compaction on base layers. Crusher run and road base shrink when they are packed. Order for the loose volume, not the finished one.
- Adding compaction to decorative stone. Pea gravel and river rock do not pack down. Ticking the box for those just buys extra stone.
- Laying loose gravel too deep. More than about 2 inches of loose pea gravel is hard to walk on, like a dry beach. Depth is not the same as quality.
- Skipping the edging. Gravel without a firm edge migrates into the lawn and the beds, and the path gets thinner every year.
- Assuming all stone weighs the same. Lava rock is half the weight of crushed stone for the same volume. Check the density for your material.
- Overloading a pickup. A cubic yard of gravel weighs around 2,700 pounds. That is beyond the payload of most half-ton trucks.
Printable shopping list
Print shopping list gives a one-page order sheet: tons, cubic yards, the bag alternative, the density assumed and your measurements. When you call the yard, read out the tonnage and ask what density they use for that product. If their figure is different, re-run the calculator with the custom density option so that your order matches their scale.
Questions people ask
- How many tons of gravel are in a cubic yard?
- For most crushed stone and gravel, between 1.3 and 1.5 tons. This calculator uses 1.35 tons per cubic yard for crushed stone, 1.3 for pea gravel and river rock, and 1.4 for crusher run. Lava rock is far lighter, at about 0.65 tons per yard.
- How much area does a ton of gravel cover?
- At 2 inches deep, a ton of crushed stone covers about 120 square feet. At 3 inches it covers about 80, and at 4 inches about 60. Lighter stone covers more and heavier stone less.
- How deep should gravel be for a path or a driveway?
- A walking path over landscape fabric needs about 2 inches. A patio or seating area needs 3 to 4 inches. A driveway needs at least 4 inches of compacted base, often 6 to 8 or more in layers, depending on your soil and climate.
- How many 50 pound bags of gravel make a ton?
- Forty. A 50 pound bag holds about half a cubic foot, so it takes roughly 54 bags to make a cubic yard. Bags make sense for a few square feet. Beyond that, loose delivery is far cheaper.
- Do I need to allow for compaction?
- Only for materials that are meant to pack down, such as crusher run, road base and decomposed granite. Loose decorative stone like pea gravel and river rock does not compact, so leave the box unchecked for those.
- Why is my supplier's quantity different from the calculator's?
- Stone from different quarries has different densities, and wet stone weighs more than dry. If your supplier gives a figure in tons per cubic yard, enter it using the custom density option and the results will match theirs.
Built and reviewed by Bertha
Last updated · How we work out our numbers