Gravel Calculator

To find how much gravel you need, multiply length × width × depth (in feet), then divide by 27 for cubic yards. A 20 ft × 10 ft area at 3 inches deep needs about 1.85 cubic yards, roughly 2.6 tons of standard gravel. Order about 10% extra for compaction.

That single calculation is the whole job of this gravel calculator: turn a length, a width, and a depth into the cubic yards, tons, and 50 lb bags you actually have to order. Buy a little surplus, and you will not be stuck spreading a patchy layer or paying for a second delivery.

The formula

Every gravel estimate comes down to volume, then a conversion to weight. The volume math is:

Length and width are in feet, depth is in inches (so divide by 12 to convert to feet), and dividing the resulting cubic feet by 27 gives cubic yards, because a cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet. To get weight, multiply the cubic yards by the gravel's density:

Standard gravel runs about 2,800 lb per cubic yard (≈ 1.4 tons), inside the 2,700 to 3,000 lb range the U.S. Army's earthmoving manual gives for dry, loose gravel. The calculator does both steps for you and lets you switch the gravel type if you are using pea gravel, crushed stone, or crusher run, or enter your supplier's own density.

Worked example with real numbers

Suppose you are graveling a small parking pad that measures 24 ft long by 12 ft wide, and you want it 4 inches deep. First the area: 24 × 12 = 288 square feet. Convert depth to feet: 4 ÷ 12 = 0.333 ft. Volume: 288 × 0.333 = 96 cubic feet, which is 96 ÷ 27 = 3.56 cubic yards. Using standard gravel at 2,800 lb per yard, that is 3.56 × 2,800 ≈ 9,956 lb, or about 4.98 tons. Add the recommended 10% overage and you would order roughly 3.9 cubic yards (about 5.5 tons). That overage covers the gravel that disappears into the sub-grade and compacts down as you tamp it.

Gravel calculation step by step (24 ft × 12 ft, 4 in deep)

Here is the same parking-pad example broken into the exact steps the calculator runs, using standard gravel at 2,800 lb per cubic yard:

How to measure your area

Accurate inputs matter more than the math. A few minutes with a tape measure saves a wasted delivery:

1. Length and width: measure in feet at the widest points. For a rough or curved shape, break it into rectangles, calculate each, and add them up.
2. Irregular shapes: for a circle, area is π × radius²; for a triangle, ½ × base × height. Convert any shape to square feet with the Square Footage Calculator, then treat it like a rectangle for depth.
3. Depth: decide the finished thickness in inches. Walkways need less, driveways need more (see below). Measure depth as the compacted layer you want, then add overage for settling.
4. Slopes and dips: if the ground is uneven, use the average depth needed to bring it level: low spots eat more gravel than you expect.

How to use this calculator

Enter your numbers and read the result at the top:

1. Length and width (feet): the footprint of the area you are covering.
2. Depth (inches): the finished gravel thickness; tap one of the 2", 3", 4", or 6" presets or type your own.
3. Gravel type: pick the closest match so the tonnage uses a realistic density, or choose Custom and enter your supplier's figure in tons per cubic yard.
4. Read the results: they update as you type. The headline shows cubic yards; the cards below show cubic feet, tons, 50 lb bags, and the amount to order with 10% extra.

The depth-coverage table then shows how the same area would change at other depths, so you can see the trade-off before you commit.

What depth do you need?

Depth is the input people most often get wrong, and it scales the order directly: doubling the depth doubles the gravel. Typical guidance:

• Decorative beds & ground cover: about 2 inches over landscape fabric.
• Walkways & garden paths: 2 to 3 inches, often over a thin base.
• Patios & light foot traffic: 3 inches of finished stone.
• Driveways: 4 inches or more for the top layer, usually over a compacted base course; heavy-use or soft-soil driveways are built deeper in multiple lifts.
• Under play equipment: pea gravel used as impact surfacing needs at least 9 inches compressed (about 12 inches installed), per the CPSC playground handbook.

How much area does a yard or ton of gravel cover?

Coverage drops as depth rises, because you spread the same volume in a thicker layer. This quick-reference table shows how far one cubic yard, and one ton of standard gravel (2,800 lb per yard), stretches at each common depth:

Ton coverage assumes standard gravel at 1.4 tons per cubic yard; lighter pea gravel covers a little more per ton and dense crusher run a little less.

Who this calculator is for

Anyone who needs to turn a project area into an order is in the right place:

• Homeowners graveling a driveway, path, patio, or fire-pit area.
• Landscapers and gardeners filling beds, French drains, or dry creek beds.
• DIY builders laying a sub-base under pavers, sheds, or concrete.
• Anyone comparing prices who needs cubic yards and tons to quote a delivery accurately.

Key terms explained

• Cubic yard (yd³): a cube 3 feet on each side = 27 cubic feet. The standard unit for bulk gravel.
• Density: the weight of gravel per unit of volume (lb per cubic yard). It converts volume to tons and varies by stone type and moisture.
• Coverage: how much area a given amount covers at a stated depth; one ton of standard gravel covers about 116 sq ft at 2 inches.
• Waste / overage factor: the extra you order (about 10%) to absorb compaction, spillage, and uneven ground.
• Crusher run: a dense mix of crushed stone and fines that compacts hard; heavier per yard and good for bases.
• Pea gravel: small, rounded stones that are lighter per yard and prone to scattering, so edging helps.

Three common scenarios

• Garden path, 40 ft × 3 ft at 2": 120 sq ft × 0.167 ft = 20 cubic feet = about 0.74 cubic yards (≈ 1.0 ton). A small job that bagged gravel could handle (42 bags of 50 lb).
• Patio, 16 ft × 16 ft at 3": 256 sq ft × 0.25 ft = 64 cubic feet = about 2.37 cubic yards (≈ 3.3 tons). Bulk delivery makes sense at this size.
• Driveway, 50 ft × 12 ft at 4": 600 sq ft × 0.333 ft = 200 cubic feet = about 7.4 cubic yards (≈ 10.4 tons). Order in tons and plan for a base layer beneath.

How much gravel for a driveway, patio or path? (scenario chart)

This matrix reads across common project sizes and down to the depth you want. Each cell is the cubic yards of gravel for that area and depth (loose volume, before overage). Multiply any figure by 1.4 for tons of standard gravel, and add about 10% for compaction when you order:

Factors that change the result

If you adjust the inputs and watch the numbers move, a few factors clearly dominate:

• Depth: the most sensitive input; it multiplies the volume directly, so a 2" vs 4" decision doubles your order.
• Area: length and width together set the footprint; an error here scales everything.
• Density / gravel type: only affects the weight (tons), not the volume. It matters when you buy by the ton.
• Compaction: gravel settles when tamped, so the in-place depth is less than the loose depth, another reason for overage.
• Sub-grade: soft or uneven ground soaks up extra gravel before you reach the finished surface.

Practical tips

• Always order about 10% extra. Running short means a second delivery charge that can outweigh the cost of a little surplus.
• Price bulk against bags once you pass a cubic yard or two: a yard of standard gravel is about 56 bags of 50 lb.
• Lay landscape fabric under decorative gravel to slow weeds and keep stones from sinking into soil.
• Compact in layers (lifts) for driveways rather than one deep pour, so the base sets up firmly.
• Confirm density with your supplier if you are ordering by weight; stated tonnage can swing 10% with stone type and moisture.

Limitations and assumptions

This is a planning estimate, not a supplier quote. A few things to keep in mind:

• It assumes a uniform, level area at a single depth; irregular ground and slopes need averaging.
• Density is an approximation; real loads vary with stone size, type, and moisture, so tonnage can differ by 10% or more.
• It does not size a separate base or sub-base course; driveways and patios usually need one beneath the decorative layer.
• The 10% overage covers normal spillage and compaction, but very soft sub-grade may need more.
• Delivery fees, edging, and labor are not included.

Gravel types and how their density differs

The volume your project needs never changes, but the weight you pay for does, because each gravel type has a different density. Picking the right type in the calculator keeps the tonnage realistic:

• Pea gravel (≈ 1.35 tons/yd³): small, smooth, rounded stones that drain well and feel soft underfoot. The lightest common type, good for paths, but it scatters without edging, and under play equipment it must be at least 9 inches deep once compressed.
• Standard / washed gravel (≈ 1.4 tons/yd³): the all-purpose default the calculator uses unless you change it. A safe estimate for most decorative and drainage jobs.
• Crushed stone (≈ 1.5 tons/yd³): angular fragments that lock together and stay put on slopes. Slightly heavier per yard than rounded gravel.
• Crusher run / road base (≈ 1.6 tons/yd³ loose in this calculator): a dense mix of crushed stone and stone dust (fines) that compacts into a near-solid surface, the heaviest and best choice for driveway and patio bases. Compacted in place it gets heavier still: the Ohio Department of Transportation converts compacted crushed stone or gravel base at 4,000 lb per cubic yard.

Because density only affects the tons figure, two suppliers can quote the same cubic yards but different tonnage. If you buy by weight, always match the type or enter the supplier's exact density. For non-stone landscape fill, the same idea applies: bark and wood chips are far lighter, which is why the Mulch Calculator uses a different density entirely.

Estimating cost: bulk vs. bagged gravel

Once you know the cubic yards and tons, cost follows quickly. Bulk gravel is usually priced per ton or per cubic yard delivered, while bagged gravel is priced per bag. A ton is 40 bags of 50 lb, so to compare, multiply the bag price by 40 and set it against the bulk price per ton plus the delivery fee. To turn the calculator's tonnage into a budget, multiply your tons (including the 10% overage) by your supplier's price per ton, then add the flat delivery charge. For a quick gut-check, the driveway example above (about 7.4 cubic yards, ≈ 10.4 tons) would take 415 bags of 50 lb: clearly a job for bulk delivery rather than the hardware-store aisle. Use the headline cubic-yard figure when a supplier sells by volume and the tons figure when they sell by weight; ordering in the unit your supplier quotes avoids rounding surprises.

Building it in layers: base, sub-base, and top

For anything that bears weight (a driveway, a patio, a shed pad), gravel is rarely a single layer. A typical build is a compacted sub-base of crusher run over the prepared sub-grade, then a finer top course of decorative gravel. Each layer has its own depth, so calculate them separately and add the results: run the calculator once at the base depth (often 4 to 6 inches of crusher run) and again at the top-course depth (1 to 2 inches of decorative stone). Compacting in shallow lifts (spreading and tamping a few inches at a time rather than dumping the whole load) produces a far firmer, longer-lasting surface than one deep pour. If you are pouring concrete over the base instead of leaving gravel exposed, the International Residential Code calls for a 4-inch base course of clean sand, gravel or crushed stone under slab-on-ground floors that sit below grade, with some exceptions for well-drained soils; switch to the Concrete Calculator for that layer, and size the footprint first with the Square Footage Calculator.

Related materials and calculators

The same volume math applies to most landscape materials, so a sister tool may fit better:

• Pouring a slab or footing? Use the Concrete Calculator for cubic yards of concrete.
• Filling beds with bark or wood chips? The Mulch Calculator handles cubic yards and bags.
• Spreading sand for a base or paver-setting bed? The Sand Calculator converts the same dimensions to tons.
• Need volume for any material? The Cubic Yard Calculator converts dimensions for sand, soil, or stone.
• Just sizing an area? The Square Footage Calculator gets you the footprint first.

Tackling other parts of the same outdoor project? Pour a slab or footing over the base with the Concrete Calculator when you want a solid finish instead of loose stone, cover a shed or fence with the Paint Calculator for gallons by wall area, size new shingles with the Roofing Calculator, and convert a roof slope to degrees or rise-over-run with the Roof Pitch Calculator. Reach for the gravel calculator whenever the material is loose aggregate sold by the cubic yard or ton.

Sources

• U.S. Department of the Army: FM 5-434, Earthmoving Operations (June 2000, PDF copy), Table 1-2: dry gravel 2,700 to 3,000 lb and wet gravel 2,800 to 3,100 lb per loose cubic yard.
• Ohio Department of Transportation: Construction and Material Specifications, Item 304 Aggregate Base, Table 304.07-1 (4,000 lb per cubic yard for compacted crushed stone and crushed gravel base).
• U.S. Consumer Product Safety Commission: Public Playground Safety Handbook (PDF), Table 2 (9 inches of compressed pea gravel protects falls up to 5 feet).
• National Institute of Standards and Technology: NIST Handbook 44 (2026), Appendix C (PDF) (27 cubic feet = 1 cubic yard, 2,000 pounds = 1 ton).
• The per-type densities in the calculator are typical loose values; they vary with stone type, gradation and moisture, so confirm the exact figure with your supplier when ordering by the ton.