How much gravel do I need for a 20x12 area?

A 20 x 12 ft area is 240 sq ft. At 4 inches deep the volume is 80 cubic feet. Adding 10% for compaction gives 88 cubic feet, which is 3.26 cubic yards or roughly 4.56 tons.

How many tons are in a cubic yard of gravel?

It depends on the stone, but many gravels weigh around 1.4 tons per cubic yard. Because density and moisture vary, confirm the supplier's conversion before ordering by weight.

How deep should gravel be?

Depth depends on the use. Decorative paths are often a couple of inches, while driveway base layers can be several inches compacted in lifts. Ask your supplier or contractor for the right depth.

Why add a waste allowance for gravel?

Gravel settles and compacts, and uneven ground can consume more material than the measured volume suggests. A small allowance, commonly around 10%, reduces the chance of running short.

Gravel Calculator

Enter the area and depth to estimate how much gravel you need in cubic yards, with an approximate weight in tons to help you compare bulk and bagged options.

Gravel needed

3.26 cubic yards

Approximately 4.56 tons.

Area: 240 sq ft
Volume: 88 cu ft
Cubic yards: 3.26 cu yd
Approximate weight: 4.56 tons

Planning note

Weight is approximate. Gravel density varies by type and moisture, commonly around 1.4 tons per cubic yard. Confirm the supplier's conversion before ordering by weight.

How this calculator works

The calculator finds the area, multiplies by the depth converted to feet, applies an optional waste allowance, converts to cubic yards, and estimates weight using a typical gravel density.

area        = length × width
volume      = area × (depth in ÷ 12)          cubic feet
cubic yards = volume with waste ÷ 27
tons        = cubic yards × 1.4   (approximate)

Assumptions

The area is rectangular. Split irregular areas into rectangles and add the results.
Weight uses an approximate density of 1.4 tons per cubic yard. Real density varies by stone type and moisture.
The waste allowance defaults to 10% and accounts for settling and uneven ground.

Worked example

A 20 ft by 12 ft area is 240 sq ft. At 4 inches deep the volume is 240 × 0.333 = 80 cubic feet. Adding 10% gives 88 cubic feet, or 3.26 cubic yards, which is about 4.56 tons.

Frequently asked questions

How much gravel do I need for a 20x12 area?: A 20 x 12 ft area is 240 sq ft. At 4 inches deep the volume is 80 cubic feet. Adding 10% for compaction gives 88 cubic feet, which is 3.26 cubic yards or roughly 4.56 tons.
How many tons are in a cubic yard of gravel?: It depends on the stone, but many gravels weigh around 1.4 tons per cubic yard. Because density and moisture vary, confirm the supplier's conversion before ordering by weight.
How deep should gravel be?: Depth depends on the use. Decorative paths are often a couple of inches, while driveway base layers can be several inches compacted in lifts. Ask your supplier or contractor for the right depth.
Why add a waste allowance for gravel?: Gravel settles and compacts, and uneven ground can consume more material than the measured volume suggests. A small allowance, commonly around 10%, reduces the chance of running short.

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Last updated: September 25, 2026