Getting the tonnage right before you order saves time, money, and return trips. Here's a straightforward method anyone can use.
Why Getting the Quantity Right Matters
Ordering too little means a second delivery charge and project delays. Ordering too much leaves you with material to dispose of — and aggregate isn't easy to return. A few minutes of planning before you call will save you both.
The calculation is simple: measure the area, decide on a depth, find the material's bulk density, and multiply. Our free Tonnage Calculator on this site handles the math automatically, but understanding the formula helps you make better decisions.
Step 1 — Measure the Area
For a rectangular driveway, measure the length and width in feet. Multiply them together to get the square footage. For example, a driveway that is 60 ft long and 12 ft wide has an area of 720 sq ft.
For irregular shapes, break the area into rectangles, calculate each, and add them together. It doesn't need to be exact — a 5% margin of error is fine, and you'll add a buffer anyway.
Step 2 — Choose Your Depth
For a new driveway base layer, 4–6 inches of compacted road base (crusher run) is standard. For a top dressing layer of decorative gravel, 2–3 inches is usually sufficient.
Deeper isn't always better — over-compaction or excessive depth can cause drainage problems. Stick to the recommended depth for your specific material and application.
Step 3 — Apply the Formula
The formula is: Volume (ft³) = Length × Width × Depth. Convert depth to feet if you measured it in inches (divide by 12). Then convert cubic feet to cubic yards by dividing by 27.
To get tonnage, multiply the volume in cubic yards by the material's bulk density (typically between 1.3 and 1.8 tons per cubic yard for aggregates). Road base, being denser, comes in at around 1.5 tons/yd³. River gravel is closer to 1.3.
Our Tonnage Calculator accepts feet, inches, metres, or centimetres — and pulls the density automatically when you select a product. Use it to double-check your manual calculation.
How Much Extra Should You Order?
Add 10–15% to your calculated quantity to account for compaction, spillage, and slight measurement error. For road base, compaction alone typically reduces volume by 10–20%, so erring on the high side is standard practice.
If in doubt, call us. We're happy to check your numbers before you place an order — it's quicker than a return delivery.
