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Pea Gravel Calculator

Work out how much pea gravel a path or border needs — volume, weight and bags, with the density set from your supplier's figure.

Pea gravel is the small, rounded stone for paths and borders — and like all aggregates it is sold by weight and by the bag, so this calculator gives you the volume, the tonnes and the bags together.

The density default of 1,500 kg/m³ is typical. Your supplier's figure is better when you have it.

Rectangle only — leave blank for a circle or a known area.
Circle only.
Use this only if you already know the area.
Paths are usually 2–4 in deep.
10% covers uneven spreading and settling.
Typical pea gravel is about 1,500 kg/m³ — change this to your supplier's figure. No universal weight is assumed.
Leave blank if buying in bulk. Common: 40 L bags.
Enter your local price — the calculator never guesses prices.

Formula

area = length × width (rectangle) or π × (diameter ÷ 2)² (circle) volume = area × depth weight = volume × density weight in tonnes = volume (m³) × density (kg/m³) ÷ 1,000 bags = ⌈ volume with wastage ÷ bag volume ⌉ (when a bag size is given) Default density 1,500 kg/m³ is a typical figure — change it to your supplier's.

All lengths are converted to a single unit before the calculation: 1 ft = 0.3048 m, 1 in = 25.4 mm, 1 ft² = 0.09290304 m², 1 yd² = 9 ft². Material quantities are rounded up — you cannot buy part of a tile, plank or bag.

How to use this calculator

  1. Choose the shape of the area (rectangle, circle, or a known area).
  2. Enter the depth — 2–4 in is normal for paths.
  3. Check the density against your supplier's figure (default 1,500 kg/m³).
  4. Enter a bag size if buying in bags, and a price per tonne for a cost estimate.

Worked example

Area10 ft × 10 ft = 100 ft²
Volume (3 in deep)100 × 0.25 ft = 25 ft³ = 0.93 yd³
With 10% wastage0.93 × 1.10 = 1.02 yd³ (0.78 m³)
Weight (1,500 kg/m³)0.78 × 1,500 = 1,170 kg = 1.17 tonnes
Bags (40 L bags)⌈0.78 ÷ 0.04⌉ = 20 bags

Check it by hand: every step above uses the formula in the box. If your numbers match the example inputs but the calculator gives a different answer, please report it via the contact page.

Frequently asked questions

How much pea gravel do I need for a path?

Multiply the path area by the depth. A 10 × 10 ft area at 3 in deep needs 1.02 yd³ — about 1.17 tonnes or 20 bags of 40 L. This calculator does the same maths for your path.

How much does pea gravel weigh?

Typically about 1,500 kg/m³, but it varies by supplier and moisture. This calculator defaults to 1,500 and lets you change it — the weight is only as good as the density you enter.

How deep should pea gravel be?

2–4 in (50–100 mm) for paths and borders. Less shows the ground beneath; more shifts underfoot. Put a weed membrane underneath first.

What is the difference between pea gravel and gravel?

Pea gravel is small (5–10 mm), rounded and decorative — for paths and borders. Construction gravel is larger and angular, for sub-bases and drainage. Use the gravel calculator for that.

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Estimates only. Results are for planning. Measure twice, confirm box coverage and tile sizes on the packaging you buy, and follow the manufacturer's instructions. See the disclaimer.