Gravel Calculator

What is a gravel calculator?

A gravel calculator estimates the volume and weight of gravel you need for a driveway, path, patio base or drainage layer — in cubic yards (how loose stone is usually sold) and in tons (how it is usually weighed at the quarry). You enter the length and width of the area in feet plus the depth in inches, and it returns the order quantity and an optional cost.

It removes the awkward unit juggling: depth is given in inches, area in feet, and gravel is priced by the cubic yard or ton. The tool converts all of it in one step so you can order the right amount and avoid a second delivery fee.

How is gravel quantity calculated?

The formula is cubic yards = length × width × (depth ÷ 12) ÷ 27, then tons = cubic yards × density. Length and width are in feet and depth is in inches, so dividing depth by 12 converts it to feet, and dividing the resulting cubic feet by 27 converts to cubic yards.

There are 27 cubic feet in a cubic yard (3 × 3 × 3 ft), which is the constant doing the heavy lifting. Density defaults to 1.4 tons per cubic yard for typical gravel and crushed stone, so multiplying cubic yards by 1.4 gives tonnage. If you also enter a price per ton, the cost is simply tons × price per ton.

What are some worked examples?

A 20 ft × 10 ft path at 3 inches deep needs about 1.85 cubic yards or 2.59 tons. Here are two reproducible calculations that match the calculator exactly.

Example 1 — a garden path, 20 ft × 10 ft at 3 inches:

• Volume = (20 × 10 × (3 ÷ 12)) ÷ 27 = (200 × 0.25) ÷ 27 = 50 ÷ 27 = 1.85 cubic yards
• Weight = 1.85 × 1.4 = 2.59 tons
• Cost at $40/ton = 2.59 × 40 ≈ $104

Example 2 — a driveway, 40 ft × 12 ft at 4 inches:

• Volume = (40 × 12 × (4 ÷ 12)) ÷ 27 = (480 × 0.333) ÷ 27 = 160 ÷ 27 = 5.93 cubic yards
• Weight = 5.93 × 1.4 = 8.30 tons
• Cost at $42/ton = 8.30 × 42 ≈ $348

Tip: ordering 10% extra on Example 1 turns 1.85 cubic yards into about 2.04 cubic yards (2.85 tons) — enough to cover settling and compaction without a top-up run.

How much area does a cubic yard of gravel cover?

One cubic yard covers about 108 square feet at 3 inches deep. Coverage depends only on depth: the shallower the layer, the more ground a yard spreads across. Use this table to sanity-check an order before you buy.

Depth	Area covered by 1 yd³	Approx. tons (at 1.4)
2 in	162 sq ft	1.4
3 in	108 sq ft	1.4
4 in	81 sq ft	1.4
6 in	54 sq ft	1.4

Note that 1 cubic yard always weighs the same (about 1.4 tons) regardless of depth — only the area it covers changes.

Does gravel density change the tonnage?

Yes — heavier stone means more tons per cubic yard, so the same hole can need a different weight of material. Pea gravel is lighter and angular crushed stone or compacted road base is denser. Adjust the density input to match your product; here is how 5 cubic yards converts at common densities.

Material	Typical density (tons/yd³)	Tons for 5 yd³
Pea gravel	1.25	6.25
Washed river gravel	1.35	6.75
Standard gravel (default)	1.40	7.00
Crushed stone / road base	1.50	7.50

These are planning figures. Moisture, fines content and stone size shift the real density, so your supplier’s quoted tons-per-yard is always the most accurate input.

What are common use cases?

Gravel calculations cover most loose-aggregate landscaping and groundwork projects. Typical jobs include:

• Gravel driveways — usually 4–6 inches deep, often in two layers over a compacted sub-base.
• Garden paths and walkways — 2–3 inches is plenty for foot traffic.
• Patio and paver bedding — a crushed-stone base beneath sand or slabs.
• Drainage trenches and French drains — clean washed stone around perforated pipe.
• Shed and base pads — a stable, free-draining foundation layer.

For paving over a stone base, pair this with the asphalt calculator, and for concrete footings see the other tools on the construction calculators page.

What are the tips, mistakes and limitations to know?

The biggest mistakes are forgetting the settling allowance and guessing the density. Keep these points in mind:

• Add ~10% for settling and compaction. Gravel loses volume as it is driven on and rain washes fines into the sub-grade.
• Use the right depth. A path that is too shallow rutts quickly; a driveway under 4 inches will not hold up to vehicles.
• Measure irregular areas in sections. Break an L-shaped or curved area into rectangles, calculate each, and add the results.
• Confirm the unit your supplier sells in. Some price per ton, others per cubic yard — the calculator gives you both so you can compare quotes.

Limitations: this tool assumes a flat, even layer and a rectangular footprint. It does not account for slope, deep sub-grade voids, or oversized rock that bridges and leaves gaps. Densities are industry averages, not lab values. Treat the result as a close planning estimate, round up to whole delivery units, and verify the final quantity with your supplier before ordering. These figures are general construction estimates and not engineering or load-bearing design advice.