Gravel Calculator

The formula

Coverage and yield assumptions

Densities are typical loose values: crushed stone or #57 about 1.4 t/yd³, pea gravel about 1.35, road base or crusher run about 1.5 (it has fines that pack tight), and river rock about 1.3. Moisture, rock type and gradation change the figure, so ask your supplier for theirs. The US Geological Survey reports crushed stone as the most used construction aggregate in the country.

Driveways

A typical gravel driveway uses three layers: 4–6 in of large stone (#3 or #4) as a base, 3–4 in of mid-size stone, and 2–3 in of surface gravel such as #57 or crusher run. Run each layer through the calculator separately. A crown or cross-slope of about 1/4 in per foot sheds water to the sides.

Paths and patios

Walkways usually need 3–4 in of gravel over landscape fabric. Pea gravel is comfortable underfoot but shifts; decomposed granite and crusher fines compact to a firm surface. Use rigid edging to keep stone in place, especially next to lawns.

Drainage uses

Clean, washed stone with no fines, such as #57 or 3/4 in drain rock, lets water pass. It is used behind retaining walls, around French drains and under sheds. Road base with fines compacts hard and is better for driveways and paver bases.

Ordering

• Many yards have a minimum delivery, often 3–5 tons.
• A pickup truck bed typically holds 1–2 cu yd, but check your payload limit since gravel is heavy.
• Have the driver spread from the truck while moving to save work.

Common mistakes to avoid

• Ordering by cubic yards when the yard sells by the ton, or vice versa.
• Using rounded decorative stone for a driveway base, where it will not lock together.
• Skipping geotextile fabric over soft clay soils.
• Forgetting to account for compaction of road base.
• Overloading a pickup truck with dense stone.

Waste factor

10% is the default because gravel compacts and spreads at edges. Use 15–20% for road base that will be compacted with a plate compactor or roller, and 5% for decorative top dressing over a firm base.

Imperial and metric

Switch the toggle above the inputs to enter ft ↔ m, in ↔ cm. The page converts metric entries to imperial before calculating, using NIST factors (1 ft = 0.3048 m, 1 in = 2.54 cm), and shows key results in both systems.

Worked examples

Path base 20 × 10 ft, 4 in

Inputs: length 20 ft; width 10 ft; depth 4 in; gravel type: Crushed stone / #57 (~1.4 t/yd³); waste factor 10%.

Result: You need 3.8 tons of gravel (2.72 cu yd).

• Units to buy (rounded up): 3.9 tons
• Area: 200 sq ft (18.6 m²)
• Volume: 73.3 cu ft (2.08 m³)
• Metric tonnes: 3.45 t

Driveway 60 × 12 ft, 6 in road base

Inputs: length 60 ft; width 12 ft; depth 6 in; gravel type: Road base / crusher run (~1.5 t/yd³); waste factor 15%; cost per unit $38.

Result: You need 23 tons of gravel (15.33 cu yd).

• Units to buy (rounded up): 23 tons
• Area: 720 sq ft (66.9 m²)
• Volume: 414 cu ft (11.72 m³)
• Metric tonnes: 20.87 t
• Estimated material cost: $874.00

Pea gravel play area

Inputs: length 12 ft; width 12 ft; depth 3 in; gravel type: Pea gravel (~1.35 t/yd³); waste factor 5%.

Result: You need 1.89 tons of gravel (1.4 cu yd).

• Units to buy (rounded up): 1.9 tons
• Area: 144 sq ft (13.4 m²)
• Volume: 37.8 cu ft (1.07 m³)
• Metric tonnes: 1.71 t

Quick reference for common sizes

The table repeats the first worked example at smaller and larger sizes, keeping every other setting the same, so you can see how the gravel calculator result scales.

Limitations

Density varies by source and moisture, so tons are an estimate; cubic yards are more reliable. The tool assumes uniform depth over a rectangle.