Pea Gravel Calculator — Volume, Weight & Bags

Formula

How this is calculated

Pea gravel refers to small (roughly 3–10 mm), smooth, rounded stones — a washed, naturally worn aggregate used for decorative paths, playgrounds, dog runs, drainage layers, and pond surrounds. Because the rounded particles pack together more uniformly than angular crushed aggregate, pea gravel has a slightly higher bulk density — about 1.68 tonnes per cubic metre (ranging roughly 1.60–1.76 t/m³ depending on stone size and moisture). This calculator uses 1.68 t/m³ as its default.

The volume is simply area × depth: for a rectangle that is length × width × depth; for a circle it is π × radius² × depth. All dimensions are converted to metres internally (1 ft = 0.3048 m, 1 in = 0.0254 m, 1 cm = 0.01 m) so the result is in cubic metres, then also shown in cubic yards (1 m³ ≈ 1.308 yd³). Multiplying by the density gives the weight in tonnes (and US short tons). The bag count uses a common retail bag size of 0.5 cubic feet (≈ 0.014 m³) and rounds up to the nearest whole bag.

For a decorative path or garden bed, 5–8 cm (2–3 in) of depth is typical. For a playground safety surface, 15–20 cm is recommended. Order 5–10% extra to account for compaction, spillage, and uneven ground.