Gravel Calculator
Enter your area and depth in millimetres to see how many cubic metres and tonnes of Granular A, 3/4 inch clear stone and pea gravel you need, and what it should cost in CAD.
Formulas shown on this page · Last reviewed October 2026
How the gravel calculator works
volume (m³) = length (m) × width (m) × depth (mm) ÷ 1,000
tonnes = volume × (1 + extra) × density (t/m³)
Gravel is sold by weight, so the calculator multiplies volume by an approximate loose density. Crushed rock and base materials are roughly 1.6 t/m³ and rounded decorative stone about 1.5 t/m³, but moisture and grading change this – ask your supplier for their figure and edit the density above. The default extra of 10% allows for compaction and uneven ground.
Typical gravel depths
| Use | Depth |
|---|---|
| Decorative gravel on a garden path | 40–50 mm |
| Gravel driveway surface | 50–75 mm |
| Granular A, compacted in lifts (about 150 mm under pavers and patios) | 100–150 mm |
| Drainage trench or French drain | Fill to trench depth |
Buying gravel in Canada
Landscape and aggregate yards sell gravel by the tonne, though many people still ask for cubic yards, so both are shown below. Popular choices include Granular A, 3/4 inch clear stone and pea gravel. Where winters bring freeze–thaw cycles, a deep, well-compacted granular base and clear stone for drainage help prevent heaving and frost damage.
Yards weigh the load on a scale, so you pay by the tonne actually delivered. Ask for a scale ticket and keep a little spare for settling.
At the default price of $35 per tonne for granular a (base gravel), one cubic metre (about 1.6 tonnes) costs roughly $56.00. These are typical prices – check your local supplier, as delivery charges and minimum loads vary by region.
Frequently asked questions
How much gravel do I need for a 5 × 3 m area at 75 mm deep?
The base volume is 1.125 m³. Adding 10% gives 1.24 m³, which is about 1.98 tonnes at 1.6 t/m³.
How many tonnes of gravel are in a cubic metre?
Roughly 1.5–1.6 tonnes for most crushed and decorative gravel, so 1.6 t/m³ is used as the default here. The exact figure depends on the material and moisture.
How many cubic yards is that?
One cubic yard is 0.765 m³, so 1.24 m³ is about 1.62 yd³.
How much extra gravel should I add?
Around 10% is a sensible allowance for compaction, uneven ground and spillage. Add more under pavers or driveways where the base is compacted hard.