How to use the gravel calculator
- Pick the material. The weight per cubic yard changes automatically. You can still change it under Adjust assumptions.
- Choose the shape. Use Rectangle for most beds and paths, Circle for round beds, or Several parts to add up an L-shape or an odd area.
- Enter the depth. This is the finished depth after spreading. Not sure? See the depth guide below.
- Read the result. You get cubic yards (what most suppliers sell by), tons (what quarries and some yards sell by) and the number of bags.
The gravel formula
Cubic feet = length × width × (depth in inches ÷ 12)
Cubic yards = cubic feet ÷ 27
Tons = cubic yards × tons per cubic yard
Bags = cubic feet ÷ cubic feet per bag, rounded up
There are 27 cubic feet in a cubic yard because a yard is 3 feet, and 3 × 3 × 3 = 27. Depth is the part people get wrong most often: 3 inches is 0.25 feet, not 0.3.
Worked example
A 20 ft × 10 ft area, 3 inches deep
- Area = 20 × 10 = 200 sq ft.
- Volume = 200 × (3 ÷ 12) = 50 cu ft.
- Add 5% for settling: 50 × 1.05 = 52.5 cu ft.
- Cubic yards = 52.5 ÷ 27 = 1.94 cu yd.
- Tons at 1.4 tons per yard = 1.94 × 1.4 = 2.72 tons.
- In 0.5 cu ft bags: 52.5 ÷ 0.5 = 105 bags, which is why bulk delivery makes sense for a job this size.
How deep to lay gravel
These are general starting points, not a design. Ground conditions, climate and how the area is used all change the answer.
| Use | Typical surface depth | Notes |
|---|---|---|
| Decorative bed or ground cover | 2 in | Over landscape fabric to slow weeds |
| Garden path or walkway | 2 to 3 in | Edging keeps it in place |
| Patio of loose gravel | 3 to 4 in | Over a compacted base |
| Base under pavers | 4 to 6 in | Compacted crushed stone, plus about 1 in of sand |
| Driveway surface layer | 3 to 4 in | Over a much deeper compacted base; get local advice |
Weight of common materials
These are the starting values the calculator uses. Real material varies with size, type and moisture, so treat them as typical, not exact.
| Material | Tons per cubic yard (typical) | Pounds per cubic yard |
|---|---|---|
| Gravel, pea gravel, crushed stone | 1.4 | about 2,800 |
| Road base / crusher run | 1.5 | about 3,000 |
| River rock | 1.35 | about 2,700 |
| Sand (dry) | 1.35 | about 2,700 |
| Topsoil | 1.1 | about 2,200 |
| Mulch | 0.3 | about 600 |
Bags or bulk?
A common bag of gravel holds 0.5 cubic feet and weighs around 50 lb. One cubic yard is 54 of those bags, about 1.35 tons to lift and carry. Bags make sense for topping up a small bed. For anything over about a yard, a bulk delivery is usually cheaper per ton and arrives where you need it. Ask about minimum orders and whether the truck can reach your drop spot without damaging the lawn or driveway.
Common mistakes to avoid
- Treating inches as decimals of a foot. 3 inches is 0.25 ft, 4 inches is 0.333 ft, 6 inches is 0.5 ft.
- Forgetting compaction. Crushed stone compacts by several percent when rolled or tamped. Order a little extra.
- Using one weight for everything. Mulch weighs about a fifth of gravel. Pick the right material.
- Measuring only the middle. Beds and driveways are rarely perfect rectangles. Split odd shapes into parts.
- Ordering exactly to the decimal. Suppliers sell in half or whole yards. Round up.
Frequently asked questions
How much does a cubic yard of gravel weigh?
Roughly 1.4 tons (about 2,800 lb) for typical gravel, but it ranges from about 1.3 to 1.5 tons depending on the stone, its size and how wet it is. Ask your supplier for their figure and enter it under "Adjust assumptions".
How much area does a ton of gravel cover?
At 1.4 tons per cubic yard, one ton is about 0.71 cubic yards, or 19.3 cubic feet. That covers about 77 sq ft at 3 inches deep, 116 sq ft at 2 inches, or 58 sq ft at 4 inches.
How do I convert cubic yards to tons?
Multiply cubic yards by the weight per cubic yard. For gravel at 1.4 tons per yard, 2 cubic yards is 2.8 tons. To go the other way, divide tons by 1.4.
How deep should gravel be?
As a general guide, decorative beds and paths use 2 to 3 inches, and driveway surface layers 3 to 4 inches over a compacted base. Driveways and anything carrying weight need a proper base built for your soil and climate, so check local guidance or ask a contractor.
Should I buy gravel in bags or in bulk?
Bags are handy for small jobs under about half a yard. Beyond about one cubic yard, bulk delivery is usually far cheaper and saves carrying dozens of 50 lb bags. A typical 0.5 cu ft bag holds about 1/54 of a cubic yard.
Why add extra gravel?
Gravel settles and compacts, some is lost at the edges, and the ground is rarely perfectly flat. Adding 5 to 10% avoids a second delivery.