How do I calculate how much tarmac I need?

Work it out in three steps. First, calculate the area: length in metres × width in metres = area in square metres. Second, calculate the volume: area × thickness in metres = volume in cubic metres. A typical driveway layer is 50mm, which is 0.05m. Third, calculate the tonnage: volume × density. Hot-mix tarmac is roughly 2,300kg per m³, so multiply the cubic metres by about 2.3 to get tonnes. For example, a 40m² driveway at 50mm thick equals 40 × 0.05 = 2m³ × 2.3 ≈ 4.6 tonnes. The calculator does this automatically.

How thick should a tarmac driveway be?

For a residential driveway, aim for a total of 70~100mm: a 50~70mm binder course plus a 20~30mm wearing course. Set the thickness field to match what you actually plan to lay, as small changes in depth have a big effect on tonnage and cost.

Tarmac & Asphalt Calculator

Q: How many m² does a tonne of tarmac cover?

At a compacted depth of 50mm and an indicative density of 2.35t/m³, one tonne covers approximately 8.51m². At 25mm it covers approximately 17.02m², while at 100mm it covers approximately 4.26m².

Planning a new driveway or commercial paving job? Our asphalt tonnage and cost calculator helps you determine the precise amount of hot-mix asphalt required. Calculate your needs in metric or imperial units to accurately plan truckloads and control material costs.

Unit system

Length

Width

Compacted layer depth

Compacted depth of the asphalt layer (for example, 50 mm).

Material allowance (%)

A 5% allowance is a useful starting point for edges, joints and normal site losses. Enter 0–20%.

Estimated compacted density

Custom density (kg/m³)

Use kg/m³ for metric units, or lb/ft³ for imperial. Use your supplier’s figure where available.

Asphalt price per tonne (£ per tonne)

Enter the current material rate quoted by your supplier in £ per metric tonne. Leave blank to calculate quantity only. Delivery, labour, plant hire and groundwork are not included.

Introduction

Getting your tarmac or asphalt quantities wrong means wasted money, overloaded truck loads, or a half-finished driveway. This free UK asphalt and tarmac calculator takes the guesswork out of it. Enter the area you’re paving in metres, your layer thickness, the mix density and a realistic wastage allowance, and in seconds you get the three numbers that matter on a UK job: the volume in cubic metres, the total weight in tonnes (for planning deliveries), and an estimated material cost in pounds.

Use it to sanity-check contractor quotes, compare thickness options, or see how driveway size affects your budget before anyone orders a single tonne. Tarmac and asphalt are often used interchangeably in the UK, this tool works for both.

Estimate only: Actual requirements can vary because of mixture density, achieved compacted depth, surface levels, joints, edges, waste and supplier ordering increments. Confirm the final quantity, minimum order and delivery details with your asphalt supplier.

How to Use Asphalt Calculator

Description of How to use the calculator

Steps	What to do
1. Choose units	Start by selecting the Unit system so everything stays consistent. Pick the option you actually use on site (feet/yards or metres). This keeps area, thickness, and output in the same language for clear, accurate results.
2. Enter area	Measure the section you’re paving and type the numbers into Length and Width. For awkward shapes, use average dimensions or split the job into simple rectangles and run the calculator for each part to keep the estimate realistic.
3. Set asphalt thickness	Enter the finished layer Thickness. This field has a big impact: small changes here can swing total volume and weight, which affects truck loads, schedule, and overall cost. Take a moment to match what you actually plan to lay.
4. Adjust density, wastage, and cost	Choose the Density that fits your mix, then add a sensible Wastage (%) to cover edges, joints, and normal site losses. If you know your rate, fill in Cost per unit so the calculator can turn volume into money.
5. Calculate and review	Click Calculate and review the volume, total weight (for logistics and trucks), and estimated material cost. Tweak any field, hit Calculate again, and use the updated numbers to tighten both planning and budget control.

How the asphalt calculation works

Asphalt quantity is normally estimated from the surface area, compacted layer depth and compacted mixture density. The calculator first converts the entered depth from millimetres to metres, calculates the compacted volume and then multiplies that volume by the selected density.
Area (m²) = length (m) × width (m)
Volume (m³) = area (m²) × depth (mm) ÷ 1,000
Asphalt tonnes = volume (m³) × compacted density (t/m³)
Order quantity = asphalt tonnes × (1 + allowance ÷ 100)

Worked Example

Worked example
A driveway measuring 10 metres long and 4 metres wide has an area of 40 m². At a compacted depth of 50 mm, the volume is 2.00 m³. Using an estimated asphalt density of 2.35 t/m³:
40 × 0.05 × 2.35 = 4.70 tonnes
Adding a 5% material allowance gives:
4.70 × 1.05 = 4.94 tonnes

The practical order estimate would therefore be approximately 5.0 tonnes, subject to the supplier’s minimum order, mixture density and delivery arrangements.

Which asphalt density should I use?

Compacted density varies according to the mixture, aggregate grading, binder content and project specification. Select the closest matching mixture from the calculator or enter the density supplied by the asphalt producer. Do not use loose aggregate density for compacted asphalt.
The preset values are suitable for preliminary estimating only. Use the mixture specific density or spread rate supplied by the producer for purchasing and project planning.

Asphalt mixture	Indicative compacted density
General asphalt estimate	2.35 t/m³
AC 10 surface course	2.35 t/m³
AC 20 binder course	2.39 t/m³
AC 32 base course	2.39 t/m³
SMA 6 or SMA 10	2.44 t/m³

How much area does one tonne of asphalt cover?

Coverage depends on compacted depth and mixture density. The following figures use an indicative density of 2.35 t/m³. They are compacted coverage estimates. Actual yield can vary because of surface irregularities, mixture density, joints, edges, waste and the achieved compacted thickness.

Approximate coverage per tonne based on specified compact depth.

What asphalt depth should I enter?

Enter the compacted depth of the asphalt layer you are estimating. A resurfacing layer, surface course, binder course and base course can each have different specified depths and densities.
The correct pavement construction depends on the ground conditions, traffic loading, drainage, sub-base, asphalt mixture and whether the work is a new installation or resurfacing. The calculator estimates material for the depth entered; it does not determine the structural design of the driveway or road.
For a multi-layer construction, calculate each layer separately using its own compacted depth and density, then add the resulting quantities.

Tarmac & Asphalt Driveway Costs in the UK (2026)

Project Type	Typical Cost in UK
New tarmac driveway (full install)	£45~£100 per m²
Resurfacing existing solid base	£20~£55 per m²
Supply-only hot-mix tarmac	£45~£60 per tonne
Porous / permeable asphalt	£85~£120 per m²
Coloured / decorative tarmac	+10~20% on standard
Single-car driveway (~20 m²)	Around £2,200
Two-car driveway (~50 m²)	Around £4,500

Prices include typical labour and standard sub-base preparation unless stated. Costs are guide figures for 2026 and vary by region, site access and groundwork always get a local quote before committing.

UK asphalt terminology and standards

Asphalt is a mixture of mineral aggregate, filler and bitumen binder. Modern UK road and driveway surfacing commonly uses asphalt concrete, stone mastic asphalt, hot rolled asphalt and other project-specific mixtures. The word “tarmac” is widely used informally for black driveway surfacing, although modern material normally uses bitumen rather than road tar.

Asphalt mixtures are specified under the relevant parts of the BS EN 13108 series, with supporting UK guidance including PD 6691. BS 594987:2024 covers requirements for transporting, laying and compacting asphalt for roads and other trafficked areas.

This calculator uses common UK mixture terminology for preliminary quantity estimates. It does not replace a pavement design, supplier specification, contractor survey or project-specific requirements.

Frequently Ask Questions

For a full new installation in 2026, most UK tarmac and asphalt driveways cost between £45 and £100 per square metre, with around £90~£100 per m² being typical for a complete job including sub-base reparation.
Resurfacing an existing solid base is cheaper, usually £20–£55 per m². Prices run roughly 10–20% higher in London and the South East. As a quick estimate, multiply your area in m² by a mid-range figure such as £90 to get a starting budget, then plug your own rate into the calculator above.

Work it out in three steps:

Area: Length (m) × Width (m) = area in square metres.
Volume: Area × Thickness (m) = volume in cubic metres. A typical driveway layer
is 50mm (0.05 m).
Tonnage: Volume × density. Hot-mix tarmac is roughly 2,300 kg per m³, so multiply
your cubic metres by about 2.3 to get tonnes.

Example: A 40 m² driveway at 50mm thick = 40 × 0.05 = 2 m³ × 2.3 ≈ 4.6 tonnes.
The calculator above does this automatically.

As a rough rule, At a compacted depth of 50 mm and an indicative density of 2.35 t/m³, one tonne covers approximately 8.51 m². At 25 mm it covers approximately 17.02 m², while at 100 mm it covers approximately 4.26 m².

Supply-only hot-mix tarmac typically costs around £45~£60 per tonne in 2026. Smaller orders are less cost-effective because delivery can add £100~£150. This is the material cost only labour, sub-base and groundwork are extra on an installed job.

In everyday UK use the words are used interchangeably, but technically tarmac uses tar as the binder while asphalt uses bitumen. Modern driveways are almost always laid with bitumen-based “asphalt”, even when people call it tarmac. Asphalt tends to give a smoother, more durable finish (15–20 years) and is usually priced similarly to tarmac at £45~£65 per m² to install.

For a residential driveway, aim for a total of 70~100mm: a 50~70mm binder course plus a 20~30mm wearing course. Set the thickness field above to match what you actually plan to lay, as small changes in depth have a big effect on tonnage and cost.

The terms are commonly used interchangeably for domestic driveways. Technically, traditional tarmac used tar as the binder, while modern asphalt normally uses bitumen. Most material described as tarmac by homeowners and contractors is now a form of bituminous asphalt.