Tarmac Calculator
Estimate the volume, weight, and cost of tarmac or asphalt needed for your driveway, path, or parking area. Supports metric and imperial units with step-by-step calculations.
Driveway & Asphalt Estimator
Calculate exactly how much tarmac you need for your project
Enter the length and width of the area to be tarmacked
Standard driveway thickness is 5cm (50mm). Garden paths can be 3-4cm.
Standard tarmac density is 2.4 tonnes per cubic meter (2,400 kg/m³)
Enter the material cost per tonne to estimate total price
View the complete step-by-step calculation process
Your Tarmac Estimate
Area, volume, weight, and cost breakdown
Enter your area dimensions and depth, then click Calculate Tarmac Needed to see the full estimate.
Standard Tarmac Thickness Guide
Recommended layer thicknesses for different types of projects to ensure longevity and prevent cracking.
| Application | Base Course | Surface Course | Total Thickness |
|---|---|---|---|
| Footpath / Garden Path | N/A (single layer) | 30-40mm | 30-40mm |
| Domestic Driveway (Cars) | 40mm | 10-15mm | 50-55mm |
| Domestic Driveway (Vans/Heavy) | 50-60mm | 15-20mm | 65-80mm |
| Commercial / HGV Parking | 75-100mm | 20-30mm | 95-130mm |
| Road Surface (Light Traffic) | 60-80mm | 20-30mm | 80-110mm |
Tarmac Calculator FAQ
Everything you need to know about estimating tarmac, driveway thickness, and project planning.
To calculate how much tarmac you need, multiply the length by the width to get the area, then multiply by the depth to get the volume. Finally, multiply the volume by the density of tarmac (typically 2.4 tonnes per cubic meter) to get the total weight required. For example, a 10m x 5m driveway at 5cm deep requires 2.5m³ of tarmac, which weighs approximately 6 tonnes.
For a standard domestic driveway used by regular cars, the total thickness should be at least 50mm (5cm). This usually consists of a 40mm base course (coarser tarmac) and a 10-15mm surface course (finer tarmac). For heavier vehicles like vans or motorhomes, increase the base course to 50-60mm for a total thickness of 65-80mm.
Standard tarmac (asphalt) has a density of approximately 2.4 tonnes per cubic meter (2,400 kg/m³). This can vary slightly depending on the specific mix and aggregate used, typically ranging from 2.2 to 2.5 tonnes per cubic meter. Always check with your supplier for the exact density of their specific mix.
While it is possible to lay tarmac yourself using DIY cold-lay asphalt packs for small patches and repairs, hot-lay tarmac requires specialized machinery to heat, lay, and roll the material. For a proper, long-lasting driveway, it is highly recommended to hire professional contractors who can ensure the correct sub-base preparation, drainage, and compaction.
A well-installed tarmac driveway with a proper MOT Type 1 sub-base can last between 15 to 20 years, or even longer with regular maintenance. To maximize its lifespan, apply a sealcoat every 3-5 years to protect against UV rays and water damage, and promptly repair any cracks or potholes to prevent water from undermining the base.
Technically, tarmac (tarmacadam) uses tar as a binder, while asphalt uses bitumen (a petroleum by-product). However, in modern usage, the terms are often used interchangeably by the general public. Almost all modern ‘tarmac’ driveways are actually made of asphalt, which is more environmentally friendly, durable, and resistant to fuel spills than traditional tar-bound tarmac.
The cost of tarmac varies by region and project size, but professionally installed tarmac typically costs between £40 to £80 per square meter in the UK. The total cost depends on the condition of the existing ground, the need for a new sub-base, the removal of old surfacing, and the complexity of the area’s shape. Material costs alone are usually around £50-£70 per tonne.
Yes, a proper sub-base is absolutely crucial for the longevity of a tarmac surface. The sub-base (usually MOT Type 1 crushed stone) provides structural support, prevents cracking from ground movement, and ensures proper drainage. Laying tarmac directly on soil or grass will lead to rapid failure, sinking, and water pooling.
