Gravel driveway calculator

What is a gravel driveway calculator?

A gravel driveway calculator works out how much gravel you need to cover a rectangular driveway to a chosen depth. It takes the three measurements that define the slab of stone you are laying — length, width, and depth — and returns both the volume of gravel and its approximate weight. Because gravel is usually sold either by volume (cubic yards or cubic meters) or by weight (tons or kilograms), having both figures makes ordering and budgeting far easier.

How does the calculator work?

Enter the length and width of the driveway along with the depth of the gravel layer you want to lay. The calculator multiplies the three dimensions to get the volume, then multiplies that volume by the bulk density of gravel to estimate the weight. You can read the result in whichever unit suits your supplier: cubic meters or cubic yards for volume, and metric tons, kilograms, or pounds for weight.

Each input has its own unit selector, so you can mix and match — for example, length and width in meters with depth in centimeters — and the calculator converts everything internally before doing the math.

Formulas

The gravel volume is simply the area of the driveway multiplied by the depth of the layer. With length $L$, width $W$, and depth $d$:

The weight follows from the volume and the bulk density $\rho$ of the gravel:

Loose gravel has a bulk density of roughly $\rho \approx 1680 \text{ kg/m}^3$ (about 1.68 metric tons per cubic meter). The exact figure depends on the stone type and how dry and compacted it is, so treat the weight as a close estimate rather than an exact value.

Worked examples

Example 1: a standard driveway

A driveway is 10 m long and 3 m wide, with a gravel layer 0.1 m (10 cm) deep:

So you need about 3 cubic meters of gravel, weighing roughly 5 metric tons.

Example 2: a larger, deeper layer

A driveway is 8 m long and 4 m wide, with a 0.15 m (15 cm) deep layer:

This driveway calls for about 4.8 cubic meters of gravel, weighing just over 8 metric tons.

Estimating gravel for a driveway

• Choose a sensible depth. A new gravel driveway typically needs a total depth of 10–15 cm (4–6 in). On soft or poorly draining ground, a sub-base layer of larger stone under the finish gravel is common, which increases the total depth.
• Add a margin. Gravel compacts and settles, and some is always lost during spreading. Ordering about 5–10% extra avoids a second delivery for a small shortfall.
• Check your supplier’s units. Bulk gravel is sold by the cubic yard or cubic meter in some places and by the ton in others. This calculator gives you both so you can order in whichever unit is quoted.
• Density varies. The 1680 kg/m³ figure is a reasonable average for dry crushed stone and pea gravel. Wet gravel is heavier, and very loose material is lighter, so use the weight as a planning estimate.