A 30 × 10 ft area 4 inches deep takes 3.70 cubic yards, or about 5.19 tons.
To figure out how much gravel you need, multiply the length by the width in feet, multiply by the depth in inches, and divide by 12 to get cubic feet. Divide by 27 for cubic yards, then multiply by the stone's weight per cubic yard (about 1.4 tons for typical crushed stone, the gravel calculator's default) to get tons.
Suppliers sell gravel by the cubic yard or by the ton, so the calculator gives you both. If your supplier quotes a different weight for the stone you pick, enter it.
How to measure for gravel
- Measure the length and width in feet. For a driveway, measure the full width you want covered, not just the tire tracks. For curves or odd shapes, split the area into rectangles and add them. The square footage calculator adds up to three rectangles for you.
- Choose the depth. Use the depth table below. For layered jobs like a driveway, calculate each layer separately, since the base and top layers are often different products. For an asphalt top layer, the asphalt calculator gives the tons of hot mix.
- Measure trenches as boxes. A French drain or a footing trench is length × width × depth. Measure the actual trench width, not the shovel width.
- Decide whether you'll compact it. If you will run a plate compactor or roller over the stone, you need more loose gravel than the finished depth suggests. See the compaction note below.
- Get the weight from your supplier. Stone density varies by rock type and size. The calculator starts at 1.4 tons per cubic yard; change it if your yard quotes something else.
The gravel formula
The calculator uses:
- Cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27
- Tons = cubic yards × tons per cubic yard
Dividing by 12 turns inches into feet, and dividing by 27 turns cubic feet into cubic yards (3 × 3 × 3 ft). Stoneco's gravel guide uses the same volume formula.
Worked example (the calculator's default values)
An area 30 ft long and 10 ft wide, 4 inches deep, with stone at 1.4 tons per cubic yard:
- Volume: 30 × 10 × 4 ÷ 12 = 100 cu ft
- Cubic yards: 100 ÷ 27 = 3.70 cubic yards
- Weight: 3.7037 × 1.4 = 5.19 tons (the calculator uses the unrounded cubic yards, so it does not multiply the rounded 3.70)
The calculator shows: "You need 3.70 cubic yards of gravel. At 1.40 tons per cubic yard, that is about 5.19 tons."
For perspective, Quikrete All-Purpose Gravel comes in 0.5 cu ft bags, so this same job would take 200 bags. Bags suit small patches and post holes; anything this size is a bulk order.
Allow for compaction
Stoneco notes that compaction can reduce gravel volume by as much as 20 percent. To still reach the full depth after a 20 percent loss, divide the calculated volume by 0.8, which is the same as ordering 25 percent more loose stone. For the example above, that is about 4.63 cubic yards, or 6.48 tons. If your supplier gives you a different compaction figure for the stone you pick, use theirs.
Example: a French drain trench
Trenches use the same math with a narrow width and a deep depth. For a trench 50 ft long, 1 ft wide, and 18 inches deep, enter length 50, width 1, and depth 18. That is 50 × 1 × 18 ÷ 12 = 75 cu ft, or 2.78 cubic yards, about 3.89 tons at 1.4 tons per cubic yard. If the trench is 10 inches wide instead of a full foot, enter 0.83 as the width; small changes in width make a big difference over a long run.
Gravel depth by project
| Project | Typical depth |
|---|---|
| Driveway | 4 to 6 in per layer |
| Garden path | About 4 in |
| Patio base | 4 to 6 in |
| French drain trench | Trench 8 to 24 in deep |
Depths are from Stoneco's gravel guide. Its driveway figure is per layer, and driveways are often built in more than one. The Federal Highway Administration's gravel roads guide, for example, calls for at least 6 inches in the first layer when stone goes over stabilization fabric on soft ground. For a paver patio base, use our paver calculator, which sizes the base and sand for you. Under a poured concrete patio, Quikrete's plan uses 4 in of compacted gravel; the concrete calculator covers the slab itself, and the rebar calculator counts any rebar in it.
Driveway gravel layers: base and top
A gravel driveway is built in layers: a thicker base of larger stone and a top layer of smaller stone with fines that packs into a firm surface. Maine DEP's gravel road manual calls for a base 12 to 18 inches thick when compacted, of well-graded gravel mostly under 3 inches (nothing over 6), and a surface layer about 4 to 6 inches thick, mostly under 1/2 inch with nothing over 2 inches. Over geotextile, it puts at least 6 inches of base under the 4 to 6 inch surface. University of Kentucky Extension says rock over bare Kentucky soil needs about 12 inches for stability and that geotextile can cut that depth in half. The FHWA guide adds a rule of thumb: each layer at least twice as thick as its largest stone, so 2 inches for 1 inch stone.
| Driveway width (per 100 ft of length) | 2 in layer | 4 in layer | 6 in layer | 12 in base |
|---|---|---|---|---|
| 10 ft | 6.17 cu yd (8.64 tons) | 12.35 cu yd (17.28 tons) | 18.52 cu yd (25.93 tons) | 37.04 cu yd (51.85 tons) |
| 12 ft | 7.41 cu yd (10.37 tons) | 14.81 cu yd (20.74 tons) | 22.22 cu yd (31.11 tons) | 44.44 cu yd (62.22 tons) |
| 16 ft | 9.88 cu yd (13.83 tons) | 19.75 cu yd (27.65 tons) | 29.63 cu yd (41.48 tons) | 59.26 cu yd (82.96 tons) |
| 20 ft | 12.35 cu yd (17.28 tons) | 24.69 cu yd (34.57 tons) | 37.04 cu yd (51.85 tons) | 74.07 cu yd (103.70 tons) |
Work out each layer on its own, since the base and top stone are different products and may weigh differently. The table is loose stone at 1.4 tons per cubic yard, as the calculator gives it with a length of 100 ft. For depths measured after compaction, order more: Maine DEP multiplies by 1.11 to get 3 inches of compacted gravel, and Stoneco's loss of up to 20 percent means 25 percent more loose stone.
French drain gravel per foot, by trench size
Count only the depth that gets stone. Home Depot's method digs a trench about 18 inches deep and 9 to 12 inches wide, sets the pipe on about 3 inches of gravel, covers it with about 3 inches more, and fills the rest with topsoil: about 10 inches of stone around a 4 inch pipe. Stoneco puts French drain gravel at 8 to 24 inches deep. Gravel per foot of trench is the width times the stone depth in inches, divided by 144.
| Trench width x stone depth | Gravel per foot | Minus a 4 in pipe | 50 ft run | 100 ft run |
|---|---|---|---|---|
| 9 x 10 in | 0.63 cu ft | 0.53 cu ft | 1.16 cu yd (1.62 tons) | 2.31 cu yd (3.24 tons) |
| 12 x 10 in | 0.83 cu ft | 0.74 cu ft | 1.54 cu yd (2.16 tons) | 3.09 cu yd (4.32 tons) |
| 9 x 18 in | 1.13 cu ft | 1.03 cu ft | 2.08 cu yd (2.92 tons) | 4.17 cu yd (5.83 tons) |
| 12 x 12 in | 1.00 cu ft | 0.90 cu ft | 1.85 cu yd (2.59 tons) | 3.70 cu yd (5.19 tons) |
| 12 x 18 in | 1.50 cu ft | 1.40 cu ft | 2.78 cu yd (3.89 tons) | 5.56 cu yd (7.78 tons) |
| 12 x 24 in | 2.00 cu ft | 1.90 cu ft | 3.70 cu yd (5.19 tons) | 7.41 cu yd (10.37 tons) |
The 50 and 100 ft columns fill the whole box at 1.4 tons per cubic yard, as the calculator does (for the 12 x 18 in trench, enter width 1 and depth 18; for a 9 in trench, width 0.75). A 4 inch PVC drain pipe is 4.215 inches across the outside, per Westlake Pipe & Fittings' ASTM D2729 sheet, so it takes the place of about 0.1 cu ft of stone per foot, or 0.36 cubic yard per 100 ft. Washington State University Extension lines the trench with geotextile or weed cloth and wraps it over the gravel so soil does not fill the spaces between the stones, and slopes the trench 0.5 to 1 percent (a 1 ft drop over 100 ft is 1 percent).
Coverage per cubic yard and per ton
| Depth | 1 cubic yard covers | 1 ton covers (at 1.4 tons/yd) |
|---|---|---|
| 2 in | 162 sq ft | About 116 sq ft |
| 3 in | 108 sq ft | About 77 sq ft |
| 4 in | 81 sq ft | About 58 sq ft |
| 6 in | 54 sq ft | About 39 sq ft |
At 1.4 tons per cubic yard, one ton of stone is about 19.3 cubic feet.
Gravel for common project sizes
Straight from the calculator at its default 1.4 tons per cubic yard, with no allowance for compaction. Depths follow the table above, plus the 2 inches Select Sand & Gravel gives for small decorative stone. Bags are 0.5 cu ft, the size of Quikrete All-Purpose Gravel.
| Project | Size and depth | Cubic yards | Tons | 0.5 cu ft bags |
|---|---|---|---|---|
| Decorative stone bed | 10 × 15 ft, 2 in | 0.93 | 1.30 | 50 |
| Garden path | 3 × 20 ft, 4 in | 0.74 | 1.04 | 40 |
| Patio base | 10 × 10 ft, 4 in | 1.23 | 1.73 | 67 |
| Patio base | 12 × 16 ft, 6 in | 3.56 | 4.98 | 192 |
| Driveway | 12 × 40 ft, 4 in | 5.93 | 8.30 | 320 |
| Driveway | 12 × 40 ft, 6 in | 8.89 | 12.44 | 480 |
| Driveway | 20 × 50 ft, 4 in | 12.35 | 17.28 | 667 |
How much does gravel weigh?
Weight depends on the rock and how much fine material is mixed in:
| Material | Approximate weight | Source |
|---|---|---|
| Standard crushed stone | 1.35 to 1.4 tons per cubic yard (2,700 to 2,800 lb) | Select Sand & Gravel |
| Crusher run or road base (with stone dust) | Up to about 1.5 tons per cubic yard (3,000 lb) | Select Sand & Gravel |
| Pea gravel | About 1.4 tons per cubic yard (2,800 lb) | Select Sand & Gravel |
| Gravel, dry (loose) | 1.35 to 1.5 tons per cubic yard (2,700 to 3,000 lb) | US Army FM 5-434 |
| Gravel, wet (loose) | 1.4 to 1.55 tons per cubic yard (2,800 to 3,100 lb) | US Army FM 5-434 |
| Compacted road gravel | About 1.6 tons per compacted cubic yard | Maine DEP gravel road manual |
| Bagged all-purpose gravel | 50 lb per 0.5 cu ft bag, which works out to 1.35 tons per cubic yard | Quikrete bag size |
Denser rock like basalt or trap rock weighs more than limestone, and smaller grades with fines pack tighter. That is why the weight field is editable. For the example, the range from 1.35 to 1.5 tons per cubic yard moves the order from about 5.00 to 5.56 tons.
River rock depends on its size: Select Sand & Gravel notes that a yard of 5 inch river rock can weigh less than a yard of fine pea gravel, because there is more air and less stone in it, and that water held in and between the stones can add 10 to 15 percent to the weight. Compacted gravel weighs more per yard than loose gravel: Maine DEP's gravel road manual puts a compacted cubic yard at about 1.6 tons.
Tons of gravel to cubic yards
A ton of gravel is about 0.7 cubic yard. Divide the tons by the weight of a cubic yard: at the calculator's default 1.4 tons, a ton is 0.71 cubic yard (19.3 cu ft); at 1.35 tons, the weight of bagged gravel and lighter crushed stone, it is 0.74; and at 1.5 tons, crusher run with stone dust, it is 0.67. The US Army's FM 5-434 lists dry gravel at 2,700 to 3,000 lb per loose cubic yard, the same 0.67 to 0.74 cubic yard per ton, and wet gravel at 2,800 to 3,100 lb, or 0.65 to 0.71.
| Tons | Cubic yards at 1.35 tons per yard | Cubic yards at 1.4 tons per yard (calculator default) | Cubic yards at 1.5 tons per yard |
|---|---|---|---|
| 1 | 0.74 (20 cu ft) | 0.71 (19.3 cu ft) | 0.67 (18 cu ft) |
| 2 | 1.48 (40 cu ft) | 1.43 (38.6 cu ft) | 1.33 (36 cu ft) |
| 3 | 2.22 (60 cu ft) | 2.14 (57.9 cu ft) | 2.00 (54 cu ft) |
| 5 | 3.70 (100 cu ft) | 3.57 (96.4 cu ft) | 3.33 (90 cu ft) |
| 10 | 7.41 (200 cu ft) | 7.14 (192.9 cu ft) | 6.67 (180 cu ft) |
| 15 | 11.11 (300 cu ft) | 10.71 (289.3 cu ft) | 10.00 (270 cu ft) |
| 20 | 14.81 (400 cu ft) | 14.29 (385.7 cu ft) | 13.33 (360 cu ft) |
Pea gravel, at Select Sand & Gravel's 1.4 tons per cubic yard, uses the middle column, and crusher run or road base the last one. To go the other way, multiply cubic yards by the tons per yard, which is what the calculator does. If your supplier sells by the ton, enter its weight per yard so the tons the calculator shows match your order. 10 tons at 1.4 tons per cubic yard is 7.14 cubic yards, enough for about 579 sq ft at 4 inches deep.
Picking the right gravel
- For driveways, use crushed stone with fines. The FHWA gravel roads guide explains that good surface gravel needs three parts: stone for strength, sand to fill the gaps, and fine particles to bind it into a firm crust. Stone without enough fines won't form that crust.
- Angular beats round for traffic. According to the same guide, fractured stone embeds into the surface and resists movement much better than rounded, natural stone.
- For drainage and decoration, describe the job to your supplier and ask them to match the stone to it.
Tips for ordering and spreading
- Crown the driveway. The FHWA guide recommends about 1/2 inch of crown per foot of width (roughly 4 percent), and advises not exceeding 6 percent. On a 10 ft wide drive, the center sits about 2.5 inches higher than the edges.
- Compact in layers. The FHWA guide notes that a roller greatly improves the finished surface.
- Order in the supplier's unit. Some quote by the ton and some by the cubic yard; the calculator shows both. For sand, the sand calculator does the same for dry or wet sand.
- Have a spot ready. Bulk stone arrives as a pile. Know where the truck can dump it without blocking the work area.
Common mistakes to avoid
- Ordering the finished depth when you plan to compact. Add the compaction allowance. A 20 percent loss needs 25 percent more loose stone, not 20.
- Assuming every stone weighs the same. A heavier stone means more tons for the same cubic yards.
- Mixing inches and feet. The depth field is in inches. Entering 0.33 instead of 4 gives a result twelve times too small.
- Using rounded stone where cars drive. It doesn't lock together the way fractured stone does.
- Ignoring soft ground. On a weak subgrade, the FHWA guide pairs stabilization fabric with a thicker first layer of stone.
Frequently asked questions
How much does a yard of gravel weigh?
About 1.4 tons (2,800 lb) for typical crushed stone or pea gravel. Select Sand & Gravel gives 2,700 to 2,800 lb (1.35 to 1.4 tons) for crushed stone, about 2,800 lb for pea gravel, and up to about 3,000 lb (1.5 tons) for crusher run or road base with stone dust. The US Army's FM 5-434 lists dry gravel at 2,700 to 3,000 lb per loose cubic yard (about 100 to 111 lb per cubic foot) and wet gravel at 2,800 to 3,100 lb. Ask your supplier for the exact figure.
How many yards are in a ton of gravel?
About 0.7 cubic yard. At 1.4 tons per cubic yard, the calculator's default for crushed stone and Select Sand & Gravel's figure for pea gravel, a ton is 0.71 cubic yard (19.3 cu ft). Lighter stone at 1.35 tons per yard gives 0.74 and crusher run at 1.5 tons gives 0.67. The US Army's FM 5-434 weights for dry gravel (2,700 to 3,000 lb per loose cubic yard) give the same 0.67 to 0.74. So 10 tons is about 6.7 to 7.4 cubic yards.
What is a yard of gravel?
27 cubic feet: a cubic yard is a volume 3 ft long, 3 ft wide, and 3 ft high. A yard of typical crushed stone or pea gravel weighs about 1.4 tons (2,800 lb), covers 162 sq ft at 2 inches deep, 108 sq ft at 3 inches, and 81 sq ft at 4 inches, and fills 54 bags of 0.5 cu ft. Select Sand & Gravel puts a half-ton pickup load at 0.5 to 0.75 cubic yard.
How much gravel do I need?
About 1.23 cubic yards, or 1.73 tons, for every 100 sq ft at 4 inches deep. Multiply length × width in feet by the depth in inches and divide by 12 for cubic feet (100 × 4 ÷ 12 = 33.3), divide by 27 for cubic yards, and multiply by about 1.4 tons per cubic yard for typical crushed stone. In 0.5 cu ft bags, that is 67 bags. Order about 25 percent more loose stone if you will compact it.
How much rock do I need for landscaping?
About 0.62 cubic yards per 100 sq ft at 2 inches deep, 0.93 at 3 inches, and 1.23 at 4 inches. Select Sand & Gravel calls 2 to 3 inches the standard depth for decorative rock, and at least twice the size of the stone: about 2 inches for stones 1/2 inch or smaller, 3 to 4 inches for 1 to 2 inch stones, and 5 to 6 inches for stones 3 inches and up. Cubic yards = length × width in feet × depth in inches ÷ 324.
How much pea gravel do I need?
About 0.62 cubic yards per 100 sq ft at 2 inches deep, which Select Sand & Gravel says is usually enough pea gravel for a clean, uniform look. A play area needs far more: the CPSC playground handbook lists 9 inches of pea gravel for falls up to 5 ft and says loose fill compresses at least 25 percent, so plan on about 12 inches, or 3.70 cubic yards per 100 sq ft. Ask your supplier what its pea gravel weighs per cubic yard.
How many tons of gravel do I need for a driveway?
About 10.37 tons for a driveway 60 ft long and 10 ft wide at 4 inches deep: 7.41 cubic yards at 1.4 tons per cubic yard. Each 100 ft of a 12 ft wide driveway takes 20.74 tons per 4 inch layer. If you will compact it and expect the full 20 percent loss, order about 25 percent more loose stone: roughly 9.26 cubic yards, or 12.96 tons, for the 60 ft driveway.
How many layers of gravel for a driveway?
2: a base of larger stone and a top layer of smaller stone with fines. Maine DEP's gravel road manual calls for a base 12 to 18 inches thick and a surface layer about 4 to 6 inches thick, both measured after compaction, with at least 6 inches of base over geotextile; Stoneco gives 4 to 6 inches per layer for a driveway. For a 12 x 100 ft driveway at 1.4 tons per cubic yard, a 12 inch base is 44.44 cubic yards (62.22 tons) and a 4 inch top layer 14.81 cubic yards (20.74 tons), before the compaction allowance.
How much area does a ton of gravel cover?
About 116 sq ft at 2 inches deep, 77 sq ft at 3 inches, and 58 sq ft at 4 inches, at 1.4 tons per cubic yard. Lighter stone at 1.35 tons per yard covers about 120 sq ft at 2 inches, and crusher run at 1.5 tons about 108 sq ft.
How many bags of gravel make a cubic yard?
54 bags of 0.5 cu ft, like Quikrete All-Purpose Gravel, make one cubic yard (27 ÷ 0.5). At 50 lb a bag, that is 2,700 lb, or 1.35 tons, so a ton of bagged gravel is 40 bags, or 0.74 cubic yard.
How deep should gravel be for a path?
Stoneco uses about 4 inches for a garden path. A 40 × 3 ft path at 4 inches needs 40 cu ft, which is 1.48 cubic yards or 80 bags of 0.5 cu ft.
Should I order extra gravel?
Yes, if you'll compact it. Stoneco says compaction can shrink the volume by as much as 20 percent, and it suggests rounding your order up, for example to the next whole cubic yard. For loose decorative gravel you won't compact, the calculated volume rounded up to the supplier's next increment is usually enough.
How many cubic feet are in a ton of gravel?
At 1.4 tons per cubic yard, the calculator's default for typical crushed stone, one ton of stone is about 19.3 cubic feet. A heavier stone means more tons for the same volume, so use the weight your supplier quotes.
What is the best gravel for a driveway?
Use crushed stone with fines. The FHWA gravel roads guide explains that good surface gravel needs stone for strength, sand to fill the gaps, and fine particles to bind it into a firm crust, and that fractured, angular stone resists movement much better than rounded, natural stone.
How much gravel do I need for a French drain?
About 1.5 cu ft per foot for a trench 12 inches wide filled 18 inches deep with stone: a 50 ft trench is 75 cu ft, or 2.78 cubic yards, about 3.89 tons at 1.4 tons per cubic yard. With about 3 inches of stone under and over a 4 inch pipe (10 inches of stone), a 12 inch wide trench takes 0.83 cu ft per foot, or 0.74 after the pipe. Measure the actual trench width, since small changes add up over a long run.
Sources
- Stoneco: How to Calculate How Much Gravel You Need
- Select Sand & Gravel: How Much Does a Yard of Crushed Stone Weigh?
- Federal Highway Administration: Gravel Roads Construction and Maintenance Guide (PDF)
- Quikrete: All-Purpose Gravel
- Quikrete 0.5 cu ft, 50 lb All-Purpose Gravel (product listing)
- Select Sand & Gravel: How Deep Should Decorative Rock Be?
- U.S. Consumer Product Safety Commission: Public Playground Safety Handbook (PDF)
- US Army FM 5-434 (MCRP 3-17.7I): Earthmoving Operations, Table 1-2 (PDF)
- Select Sand & Gravel: How Much Does a Yard of Landscape Rock Weigh?
- Maine DEP: Gravel Road Maintenance Manual: A Guide for Landowners on Camp and Other Gravel Roads (PDF)
- University of Kentucky Cooperative Extension: Using Geotextiles for Feeding and Traffic Surfaces (AEN-79, PDF)
- The Home Depot: How to Install a French Drain
- Westlake Pipe & Fittings: ASTM D2729 PVC Sewer & Drain Pipe, product specification (PDF)
- Washington State University Extension, Clark County: Improving Drainage
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