Gravel & Aggregate Calculator
With length 20 ft, width 10 ft, depth 4 inch, gravel & aggregate comes to 2.47 cu yd — volume needed. It is reached in 3 steps, the last of which is 66.666667 / 27, and each one is printed on the page with its numbers filled in. The formula is the one published by National Stone, Sand & Gravel Association, not an approximation fitted to it.
Cubic yards and tons of gravel, sand, limestone or topsoil for an area at a given depth.
Formula and sources checked · How we check
Length 20 ft, Width 10 ft, Depth 4 inch, Material Gravel — 1.4 tons/cu yd
2.47 cu yd
Volume needed for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Volume
20 * 10 * (4 / 12)66.667 cu ft- Volume in cubic yards
66.666667 / 272.469 cu yd- Weight to order
2.4691358 * 1.43.457 tons
Several at once
A job is rarely one of anything. Work out the first, add it, change the figures and add the next — the list keeps what each line was, and totals them.
Ask about this in the chatGravel Tonnage by Depth Chart
Worked example
A 20 × 10 path at 4 in deep is 2.47 cubic yards, or 3.5 tons of gravel. Suppliers quote and deliver by the ton, so the tonnage is what you phone in — and compaction takes about 20% out of loose depth, so order for the depth you want after tamping.
How to work it out yourself
- 1.Measure the area in feet and the depth in inches.
- 2.Divide depth by 12, multiply by length and width for cubic feet, then divide by 27 for cubic yards.
- 3.Multiply cubic yards by the density of the material to get tons — this is what the quarry sells by.
- 4.Add about a fifth for compaction if the depth you measured is the finished, tamped depth.
How far one cubic yard goes
A cubic yard is 27 cubic feet. Spread one inch deep it covers 324 square feet, and every other depth is that figure divided by the depth in inches — which is the whole table in one sentence.
| Depth | Square feet | Square yards |
|---|---|---|
| 1 in | 324 | 36.0 |
| 2 in | 162 | 18.0 |
| 3 in | 108 | 12.0 |
| 4 in | 81 | 9.0 |
| 6 in | 54 | 6.0 |
| 8 in | 41 | 4.5 |
| 10 in | 32 | 3.6 |
| 12 in | 27 | 3.0 |
Cubic yards for a given area
| Area | 1 in | 2 in | 3 in | 4 in | 6 in | 8 in | 10 in | 12 in |
|---|---|---|---|---|---|---|---|---|
| 100 sq ft | 0.31 | 0.62 | 0.93 | 1.23 | 1.85 | 2.47 | 3.09 | 3.70 |
| 200 sq ft | 0.62 | 1.23 | 1.85 | 2.47 | 3.70 | 4.94 | 6.17 | 7.41 |
| 500 sq ft | 1.54 | 3.09 | 4.63 | 6.17 | 9.26 | 12.35 | 15.43 | 18.52 |
| 1,000 sq ft | 3.09 | 6.17 | 9.26 | 12.35 | 18.52 | 24.69 | 30.86 | 37.04 |
Suppliers deliver in whole or half yards, so round up — a truck will not bring 2.37.
Bags to the cubic yard
| Bag | Holds | Bags per yard |
|---|---|---|
| Mulch, 2 cu ft bag | 2 cu ft | 14 |
| Mulch, 3 cu ft bag | 3 cu ft | 9 |
| Topsoil or compost, 1 cu ft bag | 1 cu ft | 27 |
| Concrete mix, 80 lb bag | 0.6 cu ft | 45 |
| Concrete mix, 60 lb bag | 0.45 cu ft | 60 |
| Concrete mix, 40 lb bag | 0.3 cu ft | 90 |
Concrete is sold by weight and the yield is printed on the bag, which is why it takes 45 of the 80 lb bags to make a yard rather than the dozen people expect. Past about ten bags, ready-mix is cheaper and far less work.
Depth by use
| Use | Depth | Why |
|---|---|---|
| Mulch, established beds | 2–3 in | Deeper than 3 in holds water against stems and starves roots of air. |
| Mulch, new beds over bare soil | 3–4 in | The extra inch is what suppresses weeds for a season. |
| Topsoil over an existing lawn | 0.25–0.5 in | Any more and the grass underneath is smothered rather than fed. |
| Topsoil for a new lawn | 4–6 in | Roots need the depth once, at the start; it cannot be added later. |
| Gravel walkway | 2–4 in | Over a compacted base, not over soil. |
| Gravel driveway, surface course | 3–4 in | Over 6 to 8 in of compacted base. |
| Gravel driveway, full build | 8–12 in | Base and surface together, laid and compacted in layers. |
| Concrete patio or walkway | 4 in | Four inches is the ordinary residential slab. Follow the specification for anything carrying a vehicle. |
How much extra to order
| Reason | Add | Note |
|---|---|---|
| Compaction, crushed stone | 20% | Six inches loose settles to about five. Order for the finished depth. |
| Settling, mulch and soil | 10–15% | Organic material shrinks as it breaks down over the first season. |
| Spillage and uneven ground | 5–10% | A hole is never the rectangle it was measured as. |
| Concrete, sub-base variation | 5–10% | A slab poured half an inch deep over 200 sq ft is a third of a yard nobody ordered. |
Volume and tonnage for a 20 × 10 area by depth
| Depth (inch) | Volume needed | Volume | Weight to order |
|---|---|---|---|
| 2 | 1.23 cu yd | 33.33 cu ft | 1.73 tons |
| 3 | 1.85 cu yd | 50 cu ft | 2.59 tons |
| 4 | 2.47 cu yd | 66.67 cu ft | 3.46 tons |
| 6 | 3.70 cu yd | 100 cu ft | 5.19 tons |
| 8 | 4.94 cu yd | 133.33 cu ft | 6.91 tons |
| 12 | 7.41 cu yd | 200 cu ft | 10.37 tons |
Depth in inches, for gravel at 1.4 tons per cubic yard. Other materials scale by their own density.
What does it cost?
Typical price is $20–$60 per ton. Picked up at the quarry. Delivery is usually a flat trip charge plus tonnage, so small orders cost far more per ton.
| Item | Typical price |
|---|---|
| Crushed stone / gravel | $20–$55 per ton |
| Sand | $15–$45 per ton |
| Topsoil, screened | $20–$60 per ton |
| Delivery trip charge | $60–$200 per load |
Price ranges as of 2026. Materials pricing moves — treat these as a sanity check on a quote, not as a quote.
The formula
- Volume
20 * 10 * (4 / 12) - Volume in cubic yards
66.666667 / 27 - Weight to order
2.4691358 * 1.4
Source: National Stone, Sand & Gravel Association, USGS Mineral Commodity Summaries — construction aggregates
Questions people actually ask
- Cubic yards or tons — which do I order in?
- Tons, almost always. Quarries sell by weight because loose volume varies with moisture and grading. The cubic yard figure tells you the hole is deep enough; the tonnage is what you buy.
- How much depth do I lose to compaction?
- Roughly 20% for crushed stone under a plate compactor. Six inches of loose material settles to about five, so order for the finished depth plus a fifth.
- Why does material change the tonnage?
- Density. The same cubic yard is 1.1 tons of topsoil but 1.5 tons of crushed limestone — a 36% difference on the delivery ticket for an identical hole.
Related
- Concrete CalculatorCubic yards of concrete for a slab, round pad, footing, column, wall or stairs, with bag counts and cost.
- Square Footage CalculatorSquare footage of a room, wall, border, gable end, ring or triangle from feet-and-inches measurements, with a waste factor and the cost.
- Cubic Yard CalculatorCubic yards for any footprint and depth, with a waste allowance and the weight of the debris if you are hauling it away.
- Mulch CalculatorCubic yards and bags of mulch for a bed, with a waste allowance and a warning when the depth would smother the roots.
- Material Weight CalculatorWhat a volume of gravel, sand, topsoil or mulch weighs, and what a weight takes up, so tons quoted by a supplier can be checked against yards measured on site.
- Concrete Block CalculatorBlocks, mortar and fill for a concrete block wall, from its length and height. Blocks, courses, mortar and the concrete it takes to fill the cores.
Part of a job
- Pouring concrete — 6 pages, in the order the questions arrive
Read first
- What a Concrete Patio Costs — Materials, delivery and labour for a slab, and where the price actually moves: on a small pour the concrete is rarely the largest of the three figures.
- What a Gravel Driveway Costs — Which stone actually compacts, how deep each layer goes, and why the cheapest load is the expensive one once it has to be dug out and replaced two years later.
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