Gravel Calculator

What is a Gravel Calculator?

A gravel calculator works out how much gravel, crushed stone, pea gravel or sand you need to cover an area at a chosen depth, and how much it weighs. Enter the area directly, or its length and width, plus how deep the layer should be. The tool multiplies area by depth to give the volume in cubic meters, cubic yards and cubic feet, then multiplies by the bulk density of the chosen material to give the weight in tonnes, kilograms, US tons and pounds. Switch bags on to estimate how many 25 kg bags you need. Both metric (m, cm) and imperial (ft, in) units are supported, making it handy for driveways, paths, drainage, patios and landscaping.

How to Use

1. Choose metric or imperial units. 2. Enter the area, or switch to dimensions and enter length and width. 3. Enter the depth of the gravel layer (5-10 cm / 2-4 in is typical for paths). 4. Pick the material (gravel, pea gravel, crushed stone or sand). 5. Toggle bags on to estimate 25 kg bags, or off for bulk delivery. 6. Read the volume, weight and bags.

Formula & Definition

Volume = area × depth Weight = volume × density For example, a 10 m² area at 10 cm deep is 10 × 0.1 = 1 m³; at a gravel density of 1500 kg/m³ that is 1.5 tonnes, or about 60 bags of 25 kg.

Interpreting Results

The headline figure is the weight you need - in tonnes for metric or US tons for imperial - because gravel is usually sold by weight. The volume in cubic meters, yards and feet is shown for ordering bulk material by the load. Weight uses the bulk density of the chosen material (gravel ≈ 1500, pea gravel ≈ 1700, crushed stone ≈ 1600, sand ≈ 1600 kg/m³); damp or compacted material weighs more, so add 10-15% for compaction on paths and driveways. Bag counts are rounded up to whole 25 kg bags - for anything over about 1 m³, bulk delivery is usually cheaper than bags.

Frequently Asked Questions