Pea Gravel Calculator

How to measure for pea gravel

Measure the length and width of the area in feet (or metres). For a path, measure along its centre line for the length and take the average width. For curved beds and irregular spaces, break the area into rectangles and circles, calculate each one, and add the results together. Use the circle option for round features such as a fire-pit surround or a tree ring, entering the full diameter.

Next, decide on the depth. Pea gravel is round and smooth, so it moves underfoot more than angular crushed stone. Around 2 to 3 inches (5 to 7.5 cm) is typical for walkways and patios. Areas that will carry vehicles, or drainage trenches, usually need more depth and a compacted base of crushed stone below the pea gravel.

The pea gravel formula

Volume is area times depth. Because depth is usually given in inches, divide it by 12 to convert to feet before multiplying:

In metric, multiply metres by metres by the depth in metres (centimetres ÷ 100) to get cubic metres, then multiply by the density in tonnes per cubic metre. A commonly quoted density for pea gravel is about 1.4 US tons per cubic yard, which is about 1.66 tonnes per cubic metre. Washed, dry gravel is lighter than wet gravel, and stone types differ, so if your supplier quotes a density, enter theirs in the density field.

For bags, the calculator divides the total weight by the bag weight and rounds up. If your bags are labelled by volume instead (for example 0.5 cu ft), you can divide the cubic feet result by the bag volume. That works out to 54 half-cubic-foot bags per cubic yard.

Worked example

A garden path is 30 ft long, 4 ft wide and will be filled 3 inches deep. You add 5% extra for settling and spillage.

1. Area: 30 × 4 = 120 sq ft.
2. Volume: 120 × (3 ÷ 12) = 30 cu ft, plus 5% = 31.5 cu ft.
3. Cubic yards: 31.5 ÷ 27 = 1.17 yd³.
4. Weight: 1.17 × 1.4 = 1.63 tons (about 3,267 lb).
5. In 50 lb bags: 3,267 ÷ 50 = 65.3, so 66 bags.

The metric version of a similar path, 9 m × 1.2 m at 7.5 cm deep with 5% extra, needs about 0.85 m³, or 1.41 tonnes at 1.66 t/m³, which is 57 bags of 25 kg.

Waste, settling and compaction

Pea gravel does not compact the way crushed stone does, because the rounded stones roll past each other instead of locking together. That is why a small allowance of around 5% is usually enough to cover settling into the soil or fabric, uneven ground, and the gravel that ends up on the lawn. If the ground is soft or you are not using a base layer or fabric, consider a larger allowance. If you are laying pea gravel on top of a compacted crushed-stone base, calculate that base separately with the gravel calculator, which lets you pick a denser material.

Edging matters more with pea gravel than with most aggregates. Steel, aluminium, timber or stone edging keeps the gravel where you put it, and a permeable landscape fabric underneath reduces weeds and stops the stones sinking into mud over time.

Estimating pea gravel cost

Landscape suppliers usually sell pea gravel by the ton (or tonne) or by the cubic yard (or cubic metre), and home centres sell it in bags. The calculator shows both so you can compare them with your own prices. The prices filled in by default are examples only; enter quotes from your area to get a meaningful figure.

When you compare, remember:

• Delivery: bulk loads often carry a delivery charge and sometimes a minimum order. For small paths, bags may be cheaper overall even though the price per ton is higher.
• Handling: a ton of gravel is a lot of bags to lift and carry. Bulk delivery dumped close to the job can save hours of work.
• Extras: landscape fabric, edging, a base layer, and a wheelbarrow and rake if you do not already own them.

Where pea gravel works best

Pea gravel is popular for informal paths, patio areas with movable furniture, between stepping stones, around plants, in dog runs and as a drainage layer. Its rounded stones are comfortable underfoot and drain well. On slopes and in high-traffic areas the stones can migrate; there, crushed stone, decomposed granite or a gravel stabiliser grid may be a better fit. For playgrounds, check the safety-surface guidance that applies to your equipment before choosing a material.

Frequently asked questions

How many square feet does a ton of pea gravel cover?

At about 1.4 tons per cubic yard, one ton is roughly 0.71 cubic yards, or about 19 cubic feet. At 2 inches deep that covers about 116 square feet; at 3 inches about 77 square feet. Your supplier's density may differ, so use their figure in the calculator.

How deep should pea gravel be?

Around 2 to 3 inches (5 to 7.5 cm) is typical for walkways and patios. Driveways and French drains usually need more, often 3 to 4 inches of pea gravel over a compacted base, because the round stones shift under load.

How many bags of pea gravel make a cubic yard?

It depends on bag size. With 0.5 cubic foot bags it takes 54 bags to make a cubic yard (27 ÷ 0.5). If your bags are sold by weight, divide the total weight from the calculator by the bag weight.

Is it cheaper to buy pea gravel in bags or in bulk?

For anything larger than a small bed, bulk is usually cheaper per ton, but delivery fees and minimum loads apply. Enter both prices above to compare them for your project.

Do I need landscape fabric under pea gravel?

A permeable landscape fabric or a compacted base layer helps stop the gravel sinking into the soil and reduces weeds. Edging along the borders keeps the stones in place.

Related guides

• How Much Pea Gravel Do I Need for a Patio?Work out how much pea gravel a patio needs in cubic yards, tons and bags, with depth advice, a base layer, coverage tables and worked examples.

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