Gravel Calculator: How Much Stone Do You Need for a Driveway or Patio?

Gravel orders are one of the most commonly miscalculated material purchases in landscaping. The errors usually come from one of two places: using the wrong depth (most people underestimate how deep 4 inches actually is) or not accounting for the difference between volume and weight — because your supplier may quote either, and they are not interchangeable without knowing the material's density.

Our  handles the conversion between cubic yards, cubic feet, and tons. This guide covers the method for any gravel project.

The basic formula

Volume (cubic yards) = Length (ft) x Width (ft) x Depth (ft) / 27

Always convert depth from inches to feet first: divide by 12.

Example: 20 x 40 ft driveway, 4 inches deep

Depth in feet: 4 / 12 = 0.333 ft

Volume = 20 x 40 x 0.333 / 27 = 266.4 / 27 = 9.87 cubic yards

Add 10% waste and settling: 9.87 x 1.10 = 10.86 → order 11 cubic yards

Recommended depths by application

Application	Recommended depth	Notes
Driveway (new base)	6-8"	4" compacted base + 2-4" surface
Driveway (top-dressing existing)	2-3"	Replenishing settled gravel
Patio or walkway	3-4"	On compacted subgrade
Garden paths	2-3"	Decorative, light foot traffic only
French drain fill	Fill to spec	Often 6-12" or full trench depth
Pipe bedding	4-6" below + cover	Per local code
Playground base	9-12"	Safety standard for fall protection

New driveways need more depth than most homeowners expect. A 4-inch surface layer looks substantial, but the recommended total depth for a stable driveway is 6-8 inches minimum — often using a compacted gravel base layer of 4-6 inches topped with 2-3 inches of surface gravel.

Converting cubic yards to tons

Many gravel suppliers sell by the ton, not by the cubic yard. The conversion depends on material density.

Weight (tons) = Volume (cubic yards) x Density (tons/cubic yard)

Material	Density (lbs/cubic yard)	Density (tons/cubic yard)
Pea gravel (dry)	2,835	1.42
Crushed limestone	2,565	1.28
Crushed granite	2,700	1.35
River rock	2,700	1.35
Sand (dry)	2,700	1.35
Decomposed granite	2,565	1.28
Recycled concrete	2,025	1.01

Example: 11 cubic yards of crushed limestone

Weight = 11 x 1.28 = 14.1 tons

Gravel types and their best uses

Type	Size	Best use	Notes
Pea gravel	3/8"	Paths, play areas, drainage	Rolls easily; not ideal for driveways
Crushed stone #57	3/4"	Driveways, drainage, base	Most versatile; compacts well
Crushed stone #21A	3/4" with fines	Driveways, base layer	Fines help it compact and bind
River rock	1-3"	Decorative, erosion control	Does not compact; purely decorative
Recycled concrete	Variable	Driveway base, fill	Cost-effective; can contain rebar
Decomposed granite	Fine aggregate	Paths, patios	Compacts firm; can stain concrete

Estimating delivery and spreading

Standard dump truck: Typically carries 10-14 cubic yards or 12-18 tons. Larger tri-axle trucks carry up to 18 cubic yards. A 10-yard load of #57 crushed stone weighs approximately 13-14 tons.

Spreading coverage at different depths:

1 cubic yard covers...	At 2" deep	At 4" deep	At 6" deep
Square footage	162 sq ft	81 sq ft	54 sq ft

One cubic yard at 4-inch depth covers an 81 sq ft area — about a 9x9 ft space. For a 1,200 sq ft driveway at 4 inches, you need approximately 15 cubic yards before the waste factor.

Settling and compaction

Fresh gravel settles 10-20% after installation, especially under vehicle traffic. A driveway surfaced with 3 inches of fresh pea gravel will settle to approximately 2.5 inches after a few weeks of use. Budget for topping off after the first season.

Compacted materials like #21A with fines settle less than clean stone like pea gravel or #57. For highest stability, use a plate compactor during installation.

Calculate exact quantities for any project size and shape with the  — it outputs cubic yards, cubic feet, and tons based on your selected material.