Gravel Driveway Calculator
Enter your driveway’s length, width and depth and we work out how much gravel to order — in tonnes, US tons and cubic yards — plus the total cost.
Gravel needed (tonnes)
7.4
- Gravel needed (US tons)
- 8.16
- Volume (cubic yards)
- 5.75
- Volume (m³)
- 4.4
- Total cost
- £333.02
Volume = length × width × depth, plus your compaction/spread allowance. Mass = volume × the bulk density of the chosen gravel grade (Engineering ToolBox figures). The tonnage is what suppliers price against; cubic yards is how bulk aggregate is often ordered in the US.
How to use this calculator
Measure the driveway’s length and width in metres and enter them, then set the depth in millimetres — 50–75 mm is enough to top up an existing surface, while a fresh gravel driveway usually wants 100 mm or more (often over a compacted sub-base). Pick the gravel type that matches what you’re buying: loose dry gravel is lightest, wet or sand-blended gravel is heaviest, and each has a different weight per cubic metre. Leave the compaction/spread allowance at 10% unless you know your delivery and levelling are unusually tight, then enter your supplier’s price per tonne to get a cost.
How the calculation works
The volume is simply length × width × depth. That neat volume is multiplied by (1 + your allowance%) because loose gravel settles as it’s raked and compacted, so you order a little more than the finished layer measures. To turn volume into a weight — how gravel is usually priced and delivered — the calculator multiplies by the bulk density of the grade you chose. Those densities come from the Engineering ToolBox “densities of common materials” table: loose dry gravel ≈ 1,520 kg/m³, a typical 1/4″–2″ dry driveway gravel ≈ 1,680 kg/m³, sand-blended natural gravel ≈ 1,920 kg/m³, and wet gravel ≈ 2,000 kg/m³. Tonnes convert to US short tons (1 ton = 907.18 kg) and the volume converts to cubic yards (1 yd³ = 0.7646 m³) so you can order in whatever unit your supplier uses.
Worked example
A 10 m × 4 m driveway at 100 mm deep, 1/4″–2″ dry gravel (≈1,682 kg/m³), 10% allowance, £45/tonne: area = 40 m²; neat volume = 40 × 0.10 = 4 m³; with 10% = 4.4 m³ (≈ 5.76 cubic yards). Mass = 4.4 × 1,682 = 7,400 kg = 7.40 tonnes (≈ 8.16 US tons). At £45/tonne that’s about £333. Notice 4.4 m³ ≈ 5.76 yd³ carrying 8.16 tons works out to ≈ 1.42 tons per cubic yard — the well-known landscaping rule of thumb of “about 1.4 tons per yard of gravel”.
Frequently asked questions
How deep should a gravel driveway be?
For a brand-new driveway, aim for a total gravel depth of about 100–150 mm (4–6 inches), ideally laid in layers over a compacted sub-base so it doesn’t rut under car weight. If you’re just refreshing or topping up an existing gravel surface, 50–75 mm of new stone is usually plenty. Enter whatever depth of new gravel you’re actually buying — if you’re building up a sub-base separately, calculate that layer on its own.
Why does the answer change so much when I switch gravel type?
Because different gravels weigh different amounts per cubic metre. Loose dry gravel is around 1,520 kg/m³, whereas wet or sand-blended gravel can be 2,000 kg/m³ — roughly a third heavier for the same volume. Since suppliers sell by weight, that difference flows straight through to tonnes and cost. The cubic-yard figure, by contrast, is pure geometry and doesn’t change with grade. If in doubt about which grade you’re ordering, ask your supplier for the material’s bulk density.
Should I order in tonnes or cubic yards?
It depends where you are and who you’re buying from. UK and European aggregate is almost always sold and delivered by the tonne. In the US, loose gravel is commonly sold by the cubic yard for smaller loads and by the ton for bulk. This calculator gives you all three — tonnes, US tons and cubic yards — so you can match whichever unit is on your supplier’s price list.
How much extra should I add for compaction?
A 10% allowance is a sensible default. Loose gravel is delivered fluffed-up and settles as it’s spread, raked and driven on, so the finished, compacted layer occupies a bit less volume than what arrives on the truck. Add more (15%) if your driveway is irregularly shaped, on a slope, or you want a generous margin; running short mid-job usually means a second delivery charge, which costs far more than over-ordering by a few percent.
Does this include a sub-base or edging?
No — it calculates a single layer of the gravel grade you select. A durable driveway is often built as a compacted crushed-stone sub-base (for example MOT Type 1) with a decorative gravel wearing course on top. If that’s your plan, run the calculator once for each layer with its own depth and material, then add the results. Edging, membrane and labour aren’t included.
How accurate are the weight figures?
The volume is exact geometry, but the weight depends on bulk density, which varies with the stone’s size, shape and moisture. The densities used here are standard published figures for common gravel grades and are accurate to within a few percent for typical material. For a large order where a few percent matters, ask your supplier for the exact bulk density of the product you’re buying and treat this estimate as a close starting point.