Gravel & Stone Calculator

How much gravel do I need?

Gravel and crushed stone are sold in bulk by the cubic yard or the ton, and in bags for small jobs. To estimate a load, find the volume of the area you are filling, then convert that volume to weight (tons) using the stone's density and to bags if you are buying bagged. The calculator above does all three at once — enter your area and depth and it returns cubic yards, tons and 50 lb bags, plus an estimated cost.

The gravel formula

Volume is length times width times depth, with every dimension in the same unit. Because landscape depths are almost always given in inches while area is in square feet, the quickest shortcut keeps area in square feet and depth in inches:

cubic yards = area (sq ft) × depth (in) ÷ 324

The 324 comes from the math: a cubic yard is 27 cubic feet, and there are 12 inches in a foot, so 27 × 12 = 324. If you prefer to work entirely in feet, the long form is the same calculation:

cubic feet = length (ft) × width (ft) × depth (ft)  ·  cubic yards = cubic feet ÷ 27

Once you have cubic yards, multiply by the stone's density to get tons. Most common gravel runs about 1.4 tons per cubic yard, so:

tons = cubic yards × 1.4  ·  50 lb bags = cubic feet ÷ 0.5

Worked example: a small gravel pad

Say you are laying a 12 ft × 10 ft gravel pad at a 3 inch depth (a typical walkway or shed-base depth):

• Area = 12 ft × 10 ft = 120 sq ft
• Cubic yards = 120 × 3 ÷ 324 = 1.11 cubic yards
• Tons = 1.11 × 1.4 = 1.56 tons
• 50 lb bags = (120 sq ft × 3 in ÷ 12) ÷ 0.5 = 30 cu ft ÷ 0.5 = 60 bags

At 60 bags this job is firmly in "buy in bulk" territory — see the cost table below. Once you account for compaction (covered further down) you would round the order up to about 1.25 cubic yards or 1.75 tons.

Gravel types, weight & cost

Density and price both vary by stone type and by region. Decorative and washed stone cost more than plain crushed limestone or crusher-run. The figures below are typical 2026 US bulk ranges and are estimates only — always confirm the delivered price with a local supplier, since haulage often costs as much as the stone.

The calculator uses about 1.4 tons per cubic yard, which is representative of common driveway and drainage gravel. For heavier riprap or lighter washed pea gravel, adjust your weight estimate up or down a little.

Coverage: how far does a ton go?

A quick field rule for plain gravel: one ton covers about 100 sq ft at 2 inches deep. Coverage drops as depth rises because the same weight of stone has to spread thinner.

How deep should gravel be?

Depth depends on the job. For a walkway or drainage bed, 2–3 inches over fabric is usually enough. A driveway carries vehicle loads and is built up in layers, not a single dump:

For a driveway, lay a geotextile (landscape) fabric on the graded subgrade first. The fabric stops the stone from sinking into the soil and the soil from pumping up into the stone, which can double the life of the surface. It typically adds roughly $0.15–$0.30 per square foot in material. On top of the fabric goes a 4 inch compacted base of angular crusher-run or #57 stone, then a 2 inch surface layer.

Waste & compaction: order a little extra

Gravel settles and compacts under its own weight and traffic, so the depth you order is more than the depth you end up with. The U.S. Federal Highway Administration's Gravel Roads Construction & Maintenance Guide treats compaction as a routine part of building a gravel surface. A practical rule:

• Add about 10% for handling and overage — uneven subgrade, spillage and the last partial load.
• Add 20–30% if the gravel will be machine-compacted, as a driveway base is. Compacting a 4 inch loose lift can lose roughly an inch of finished depth.

For a loose decorative bed, the 10% buffer is enough. For a compacted driveway base, order on the high side — it is far cheaper than a second delivery.

Common mistakes

• Using rounded stone for a driveway. Pea gravel and river rock never lock together, so they shift and rut under tires. Use angular crushed stone or crusher-run for anything vehicles drive on; save the rounded stone for beds and paths.
• Skipping the fabric. Without geotextile, base stone migrates into the soil and you are topping up gravel every couple of years.
• Ignoring compaction. Ordering the exact calculated volume leaves a driveway base an inch shy of spec.
• Buying bags for a big job. Past ~12–15 bags, bulk by the yard or ton is dramatically cheaper per pound.
• Forgetting delivery. A short load can carry a flat haul fee that dwarfs the stone cost — combine deliveries where you can.

When to hire a pro

A small decorative bed or a short walkway is a confident DIY weekend. Bring in a pro when the job involves grading and drainage you can't eyeball, a long or load-bearing driveway, a slope that needs riprap or erosion control, or any cut near utilities. A contractor with a plate compactor and a laser grade will get the base right the first time, which is where most DIY gravel surfaces fail. For related estimates, see the sand, mulch and soil calculators, the cubic yards calculator, the floating deck calculator for its gravel base pad, the paver calculator if gravel is the base under a paver patio, the retaining wall calculator for its base and drainage stone, or the asphalt calculator if you're paving the driveway on top.

Figures here are estimates only and vary by region, stone type and supplier as of 2026 — verify quantities and delivered pricing with a local pro or gravel supplier before you order.