Gravel  /ˈɡrævəl/ is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel is sub-categorized by the Udden-Wentworth scale into granular gravel (>2 to 4 mm or 0.079 to 0.16 in) and pebble gravel (>4 to 64 mm or 0.2 to 2.5 in). One cubic yard of <gravel typically weighs about 3000 pounds (or a cubic metre is about 1,800 kilograms).

Gravel is an important commercial product, with a number of applications. Many roadways are surfaced with gravel, especially in rural areas where there is little traffic. Globally, far more roads are surfaced with gravel than with concrete or tarmac; Russia alone has over 400,000 km (250,000 mi) of gravel-surfaced roads.^{[citation needed]} Both sand and small gravel are also important for the manufacture of concrete.