What is the formula for calculating gravel in tons?

Tons = square feet × (depth in inches ÷ 12) × density (lb/ft³) ÷ 2,000, times a 1.10–1.15 waste factor. For common gravel at 105 lb/ft³, a useful shortcut is cubic yards × 1.42 = tons — one loose cubic yard weighs about 2,800 lb.

How many tons are in a cubic yard of gravel?

About 1.42 US tons (2,800 lb) for common gravel, loose. Pea gravel is lighter at roughly 1.3 tons per yard, #57 stone runs about 1.35 loose, and compacted crusher run reaches 1.89 tons per cubic yard. Always match the factor to the specific material you are ordering.

What depth should I calculate for?

2 inches for decorative cover over fabric, 3 inches for walkways and patios, and 4 inches per compacted lift for driveways — a new drive typically needs 8–12 inches total across two or three layers. Going below 2 inches leaves bare spots; the fabric shows within a season.

How much extra gravel should I order?

10% is the standard allowance; go to 15% for crusher run that will be compacted, soft or muddy subgrade, or hand-spreading over an undulating surface. Running short costs a second delivery fee of $50–150, so the allowance nearly always pays for itself.

Should I order in tons or cubic yards?

Order in whatever unit your supplier weighs or measures — most quarries sell by the ton off a certified scale, while landscape yards often sell by the loose cubic yard. Compute both from your volume and quote both on the phone; it flags conversion errors before the truck rolls.

Does the calculation change for crusher run or pea gravel?

Only the density changes. Pea gravel drops to 96 lb/ft³, crusher run rises to 125 lb/ft³ loose and about 140 compacted — so a crusher run order in tons runs roughly 20% heavier than common gravel for the same volume. The five steps themselves are identical for every type.

Gravel · Method Guide

How to calculate gravel

Area, depth, density, allowance — the same five steps size a garden path and a 400-ton haul road. Learn them once and every quote you receive becomes checkable.

Contents

1.The five-step method
2.The tonnage formula
3.Worked example: gravel patio (imperial)
4.Worked example: garden path (metric)
5.Key conversions
6.Same method, three materials

The five-step method

1
Measure the area
Measure length and width in feet and multiply for square feet. Split irregular shapes into rectangles and sum the pieces — precision here is cheap, and every downstream number keys off it.
2
Pick the depth
2 inches for decorative top-dressing, 3 inches for paths and patios, 4 inches per lift for driveways. Depth drives cost linearly, so choose it deliberately, not by habit.
3
Compute the volume
Square feet × (depth in inches ÷ 12) gives cubic feet. Divide by 27 for cubic yards — the unit most suppliers quote in.
4
Apply the type's density
Common gravel runs 105 lb/ft³ loose (1.42 US tons per cubic yard), pea gravel 96 lb/ft³, #57 stone 100 lb/ft³ loose, crusher run 125 lb/ft³ loose. Multiply volume by density, then divide pounds by 2,000 for tons.
5
Add a settling allowance
Order 10% extra as standard; 15% where crusher run will be compacted or the subgrade is soft. Gravel consolidates the moment it leaves the truck — the allowance is not optional padding.

The tonnage formula

Formula

Tons = ft² × (in ÷ 12) × density ÷ 2,000 × (1 + waste)

ft²: Measured area (square feet)
in: Depth (inches)
density: Loose unit weight of the type (lb/ft³)
waste: Settling allowance, 0.10–0.15 (decimal)

Common gravel: 105 lb/ft³ loose = 1,680 kg/m³ = 1.42 US tons/yd³. Divide cubic feet by 27 first if your supplier quotes cubic yards instead of tons.

Worked example: gravel patio (imperial)

Worked example

A 15 × 20 ft patio surfaced with 3 inches of common gravel over landscape fabric.

1
Area
15 × 20 = 300 ft²
2
Volume at 3 in (0.25 ft)
300 × 0.25 = 75 ft³ = 2.78 yd³
3
Weight at 105 lb/ft³
75 × 105 = 7,875 lb = 3.94 tons
4
Add 10% settling allowance
3.94 × 1.10 = 4.33 tons

Result: Order 4.5 tons (about 3 loose cubic yards) — round up to the supplier's half-ton increment.

Worked example: garden path (metric)

Worked example (metric)

A 12 m garden path, 1.5 m wide, dressed with 75 mm of common gravel.

1
Area
12 × 1.5 = 18 m²
2
Volume at 75 mm (0.075 m)
18 × 0.075 = 1.35 m³
3
Mass at 1,680 kg/m³
1.35 × 1,680 = 2,268 kg = 2.27 t
4
Add 10% settling allowance
2.27 × 1.10 = 2.49 t

Result: Order 2.5 tonnes. Metric skips the ÷27 and ÷2,000 steps entirely — cubic metres × density in t/m³ is the whole calculation.

Key conversions

The six conversions that cover nearly every gravel order. Densities for other types are in the density chart.
From	To	Operation
Inches	Feet	÷ 123 in = 0.25 ft — never multiply mixed units
Cubic feet	Cubic yards	÷ 27
Cubic yards (common gravel)	US tons	× 1.42Loose; 2,800 lb per yd³
US tons (common gravel)	Coverage at 3 in	× 76 ft²114 ft² at 2 in, 57 ft² at 4 in
Cubic metres (common gravel)	Tonnes	× 1.68
Cubic yards	Cubic metres	× 0.765

Same method, three materials

Area × depth × density is the universal takeoff. The identical five steps size a concrete pour — see how to calculate concrete — and an asphalt lift, covered in how to calculate asphalt. Only the density and the waste factor change: concrete at 150 lb/ft³, hot-mix asphalt at 145 compacted, gravel at 96–140 depending on type and compaction. Master the gravel version and the other two are substitutions.

Frequently asked questions

Run your own takeoff

The gravel calculator applies this exact method with every density and unit conversion built in.

Gravel Calculator

Go deeper

Sources & references

[1]ASTM C29/C29M: Bulk Density (Unit Weight) and Voids in Aggregate — ASTM International, 2017
[2]The Aggregates Handbook, 2nd ed. — National Stone, Sand & Gravel Association, 2013