Gravel Calculator
Enter the area and the compacted depth to get the volume of gravel in cubic yards — the unit aggregate is actually sold in.
The finished depth after compaction, not the loose depth off the truck
Showing an example. Change any figure to use your own.
- Cubic feet
- 240 cu ft
- Cubic metres
- 6.796 m³
- Order this much
- 9 cu yd
length x width x depth x (1 + waste)
Assumptions and limits
Formulalength x width x depth x (1 + waste)
This tool reports volume only. No manufacturer publishes a density or a cubic-foot yield for this material, and we do not invent one — so there is no weight or bag count to state an assumption about. Volume is the unit it is sold in.
How to measure
Gravel is ordered by the cubic yard, so the three numbers that matter are length, width and compacted depth.
Depth is where estimates go wrong. The depth you want is the finished, compacted depth — not the loose depth off the truck. Loose aggregate settles roughly 20 to 25 percent when it is plate-compacted, which is why a driveway spread to 4 inches loose finishes closer to 3.
For an existing driveway you are topping up, measure down from a straightedge laid across the surface to the old base, in several places. For a new one, measure to the compacted subgrade, not to the topsoil you have not stripped yet.
Irregular shapes are easier than they look. Break the area into rectangles, run each one separately, and add the volumes. A driveway with a turnaround is a long rectangle plus a square, and treating it as one average width will overestimate the narrow end.
A worked example
A parking apron beside a shop, 20 ft by 30 ft, 4 inches of compacted #57 stone.
Volume. 20 ft × 30 ft × 4 in = 20 × 30 × 0.3333 = 200 cubic feet, which is 200 ÷ 27 = 7.41 cubic yards.
Compaction. That is the compacted volume. Spread loose, it needs roughly 20 percent more material to compact down to 4 inches, so the order is closer to 8.9 cubic yards.
What to order. Yards are the unit, and most yards sell in half or whole yards. Call it 9 cubic yards.
This tool gives you the compacted volume — the 7.41. The compaction allowance is a judgement call that depends on the stone, the base under it and how hard you compact, so it is entered as waste rather than assumed for you.
Common mistakes
Confusing yards with tons. Aggregate yards quote in either, and they are not interchangeable. A cubic yard of dry #57 stone runs somewhere around 1.3 to 1.5 tons depending on the stone, but that figure varies enough by quarry and moisture content that we do not publish one. Ask your supplier for the conversion for the specific product, and order in the unit they quote.
Ordering the compacted volume. If you order 7.4 yards for a 4-inch compacted apron, you will finish at roughly 3 inches. Add the compaction allowance before you call.
Ignoring the base. A driveway is usually two layers — a coarse base and a finer top course — and each has its own depth. Run the calculation twice, once per layer, rather than treating the whole build-up as one depth of one material.
Rounding the depth down. An inch of depth across 600 square feet is 1.85 cubic yards. Depth moves the number far more than length or width, and it is the one measured least carefully.
Ordering
Most yards have a minimum delivery, often one to three cubic yards, and a delivery charge that is the same whether the truck is half full or full. If you are close to a threshold, the extra material is usually cheaper than a second trip.
Ask what the stone is graded as, not just what it is called. Names vary regionally; the gradation number does not. And ask whether the price is per yard delivered or per ton delivered — comparing a per-ton quote against a per-yard quote without the conversion is how two bids that look different turn out identical.
If access is tight, say so when you order. A tri-axle cannot always get where a smaller truck can, and finding that out on delivery day means the pile ends up in the wrong place and gets moved by hand.