Tarmac Calculator

How Much Tarmac Do I Need?

This free tarmac calculator works out exactly how much tarmac or asphalt you need for any surfacing project. Enter your area dimensions, select a project type to auto-fill the recommended depth, and get instant results in cubic metres, tonnes, hot-mix loads and cold-lay bags.

The calculator uses the formula: area × depth × density. Tarmac has a density of approximately 2,400 kg per cubic metre (2.4 tonnes/m³), which is denser than MOT Type 1 sub-base (2,100 kg/m³) because the bitumen binder fills the voids between the aggregate particles.

This calculator works for both hot-mix tarmac (professionally laid from an asphalt plant) and cold-lay tarmac (DIY bags from a builder’s merchant). The results show hot-mix in 8-tonne delivery loads and cold-lay in 25kg bags so you can plan either approach.

Need to calculate the sub-base underneath? Use our sub-base calculator to work out how much MOT Type 1 you need before laying tarmac. For other driveway surfaces, try the gravel calculator or concrete calculator.

Worked Examples

Single Driveway (3m × 6m)

A standard single driveway at 60mm tarmac depth:

• Area: 3 × 6 = 18 m²
• Volume: 18 × 0.06 = 1.08 m³
• Weight: 1.08 × 2,400 = 2,592 kg = 2.59 tonnes
• Hot-mix loads: 1 load (minimum delivery is typically 1–2 tonnes)
• Cold-lay bags: 104 × 25kg bags (for DIY)
• Materials cost: £270–£450

Garden Path (10m × 1m)

A garden path at 40mm tarmac depth:

• Area: 10 × 1 = 10 m²
• Volume: 10 × 0.04 = 0.40 m³
• Weight: 0.40 × 2,400 = 960 kg = 0.96 tonnes
• Cold-lay bags: 39 × 25kg bags
• Materials cost: £150–£250

Car Park (20m × 10m)

A small car park at 80mm tarmac depth:

• Area: 20 × 10 = 200 m²
• Volume: 200 × 0.08 = 16.0 m³
• Weight: 16.0 × 2,400 = 38,400 kg = 38.4 tonnes
• Hot-mix loads: 5 × 8-tonne loads
• Materials cost: £3,000–£5,000

Tarmac Depth Guide by Project Type

The thickness of tarmac you need depends on the traffic the surface will carry. Professional tarmac driveways use two layers — a coarser binder course for strength and a finer wearing course for a smooth finish. Lighter-use surfaces can get away with a single layer.

These depths assume a properly prepared sub-base underneath. Without a solid sub-base, even thick tarmac will crack and sink. Use our sub-base calculator to work out how much MOT Type 1 you need.

Tarmac vs Concrete vs Gravel

Choosing between tarmac, concrete and gravel for your driveway depends on budget, appearance and maintenance. Each surface has distinct advantages and drawbacks. Here is an honest comparison based on real UK project costs and longevity.

Tarmac is the most popular driveway surface in the UK because it offers a good balance of cost, appearance and durability. Concrete costs more upfront but lasts longer. Gravel is the cheapest option and the only one that does not typically require planning permission for areas over 5m². Calculate your gravel needs with our gravel calculator or concrete with our concrete calculator.

Tarmac vs Other Driveway Surfaces — Full UK Comparison

Beyond the three most common surfaces, block paving and resin-bound gravel are increasingly popular alternatives. Here is how all five options compare for a typical UK driveway project in 2026.

Which should you choose? For most UK homeowners on a mid-range budget, tarmac offers the best value — quick installation, clean appearance and low ongoing costs. Block paving suits those wanting a more decorative finish and who are prepared to pay more upfront. Resin-bound is the best option if you want a premium permeable surface that avoids planning permission complications entirely. Gravel remains the budget choice, and you can calculate exactly how much you need with our gravel calculator. For concrete driveways, use our concrete calculator to work out quantities.

Hot Mix vs Cold Lay Tarmac

There are two fundamentally different types of tarmac available, and choosing the wrong one for your project will lead to disappointing results.

Hot-Mix Tarmac (Professional Use)

Hot-mix tarmac is produced at an asphalt plant and delivered to site at temperatures between 140–180°C. It must be laid, levelled and compacted within 30–60 minutes before it cools and hardens. Hot-mix produces a dense, durable surface that can last 15–25 years under normal traffic. This is what professional contractors use for driveways, roads, car parks and any surface that needs to carry vehicles.

Hot-mix requires specialist equipment — a paver or hand raking by an experienced team, followed by rolling with a vibrating roller. Most domestic orders are a minimum of 1–2 tonnes. The asphalt plant mixes the material to order, so you need to book a delivery slot in advance.

Cold-Lay Tarmac (DIY Repairs)

Cold-lay tarmac comes in 25kg bags from B&Q, Wickes, Toolstation and Amazon. It can be applied at any temperature and does not need heating. It is designed for small repairs — filling potholes, patching edges, repairing cracks and topping up worn areas. Cold-lay is significantly more expensive per tonne than hot-mix and does not produce the same dense, hard-wearing finish.

Cold-lay tarmac is workable straight from the bag. Compact it firmly with a hand tamper or the back of a shovel, and it sets through a slow curing process over several weeks. It is not suitable for laying a full driveway — it remains softer than hot-mix and can deform under heavy traffic in hot weather.

How Much Does a Tarmac Driveway Cost?

Tarmac driveway costs in the UK vary by size, location and ground conditions. Here are realistic 2026 prices including labour and materials.

These prices include excavation, sub-base preparation, binder course and wearing course. Costs are 20–30% higher in London and the South East. Additional costs may apply for skip hire (£250–£350), drainage work (£500+), and kerb or edging installation (£20–£40 per linear metre).

Materials Only vs Fully Installed

Money-saving tip: Always get at least three quotes from local contractors. Ask whether the price includes sub-base excavation and disposal — some quotes exclude skip hire and you discover the extra cost after the work has started.

How Much Does Tarmac Cost in the UK? (2026 Prices)

Whether you are buying bags of cold-lay tarmac for a DIY repair or getting quotes for a professionally laid driveway, here is what you can expect to pay across the UK in 2026.

DIY Cold-Lay Tarmac Costs

Cold-lay tarmac is sold in 25kg bags at builders’ merchants and DIY stores. A single 25kg bag covers approximately 0.5m² at a 25mm depth — enough for a small pothole repair or edge patch. Expect to pay £8–£15 per bag from trade suppliers, or £12–£18 per bag at B&Q and Wickes. Premium cold-lay products with added polymer binders cost £15–£25 per bag but produce a harder, longer-lasting repair.

For a 1m² pothole repair at 50mm depth, you need roughly 4 bags (£32–£60). For a small path repair of 5m², budget for 10–12 bags (£80–£180). Cold-lay is cost-effective for repairs under 5m² but becomes prohibitively expensive for larger areas — at that point, hot-mix tarmac from a contractor is significantly cheaper per square metre.

Professional Hot-Lay Tarmac Costs

A professional tarmac contractor typically charges £40–£60 per m² for a standard driveway, which includes labour, materials and plant hire. This price assumes a straightforward job with reasonable access and existing sub-base in acceptable condition.

For a full build including excavation, new sub-base (150mm MOT Type 1), 60mm binder course and 25mm wearing course, expect to pay £50–£80 per m² all-in. The exact price depends on your location, site access, ground conditions and the amount of excavated material that needs removing.

Typical Driveway Costs by Size

Regional price variation: Prices are typically 20–30% higher in London and the South East. Scotland, Wales and the North of England tend to be at the lower end of these ranges. Access difficulty (narrow lanes, rear gardens, long distances from road to site) can add £5–£15 per m². If you need new sub-base work, use our sub-base calculator to estimate the additional aggregate quantity required.

DIY Tarmac: Can You Lay Your Own?

The honest answer depends on the scale of your project. Small repairs are straightforward DIY jobs. Full driveways are not.

What You Can DIY

Pothole repairs: Clean out the hole, apply cold-lay tarmac in 25mm layers, compact each layer firmly with a tamper. Simple, cheap and effective.

Edge repairs: Where tarmac has crumbled at the edges, cut back to a clean line, apply cold-lay and compact. Consider installing an edging strip to prevent future deterioration.

Patching worn areas: Sweep clean, apply a tack coat (bitumen emulsion spray) to help the new material bond, then spread and compact cold-lay tarmac.

What Needs a Professional

Full driveways: Hot-mix tarmac must be spread and compacted within 30 minutes. A team of 3–4 people with a roller is the minimum for a domestic driveway. The coordination between the asphalt plant delivery, spreading and rolling requires experience.

Binder course work: The lower layer needs to be laid to precise levels and falls to ensure drainage. Getting this wrong means standing water and premature failure.

Any area over 10m²: Cold-lay tarmac is not economical or practical at this scale. The per-tonne cost is 5–10 times higher than hot-mix, and the finished quality is noticeably inferior.

Sub-Base Requirements for Tarmac

Every tarmac surface needs a properly prepared sub-base. The sub-base does the structural work — it distributes the weight of traffic over a wide area and prevents the tarmac from cracking as the ground moves. Without it, even the best tarmac surface will fail within a few years.

Use our MOT Type 1 calculator to work out exactly how much sub-base you need. The sub-base should always be compacted in layers of no more than 75mm at a time using a plate compactor.

Tarmac vs Asphalt — What’s the Difference?

In everyday UK conversation, “tarmac” and “asphalt” mean the same thing. But technically they are different materials with different histories.

Original tarmacadam (patented 1901) used coal tar as the binder — a byproduct of gas production. Coal tar tarmac was the standard road surface throughout the 20th century. It was phased out in the 1980s because coal tar contains polycyclic aromatic hydrocarbons (PAHs) which are carcinogenic.

Modern “tarmac” is actually bituminous asphalt. It uses bitumen (a byproduct of oil refining) as the binder instead of coal tar. Bitumen is safer to handle and produces a more durable surface. Every “tarmac” driveway laid in the UK since the 1990s is technically asphalt.

The word “tarmac” has stuck in British English as the generic term for any black road surface, just as “hoover” means any vacuum cleaner. For practical purposes, when your contractor says “tarmac” they mean bituminous asphalt — and that is exactly what this calculator is designed for.

Planning Permission for Tarmac Driveways

Since 2008, UK planning rules require that new or replacement driveways over 5 square metres must either use a permeable surface or drain rainwater to a permeable area within your property. Standard tarmac is impermeable, so you have three options:

• Install drainage: Direct rainwater to a soakaway, lawn or planting bed on your property. Most contractors include this as standard.
• Use porous tarmac: A specialist open-graded asphalt that allows water to drain through. More expensive but avoids the planning application.
• Apply for planning permission: If you cannot provide on-site drainage, a householder planning application costs £258 (England, 2026) and typically takes 8 weeks.

Driveways under 5m² are exempt regardless of surface type. Replacing a tarmac driveway with new tarmac of the same area is also generally exempt under permitted development, provided you do not increase the impermeable area. Check with your local planning authority if you are unsure.

Conservation Areas and Listed Buildings

If your property is in a conservation area, permitted development rights may be restricted. Some local authorities require planning permission for any change to the front elevation of a property in a conservation area — and that can include driveway surfaces. Listed buildings have even stricter rules: you may need listed building consent for any alteration to the curtilage, including replacing a driveway.

Article 4 directions can also remove permitted development rights in specific areas. If your property is in a conservation area, an Area of Outstanding Natural Beauty (AONB) or a national park, contact your local planning authority before starting work. The planning portal at planningportal.co.uk has a free interactive guide that tells you whether your specific project needs permission based on your postcode and property type.

Back Garden Driveways and New Crossovers

If you are creating a brand new driveway where one does not currently exist, you will also need a dropped kerb (vehicle crossover) from the local highways authority. This is a separate application from planning permission and typically costs £800–£2,500 depending on your council. It can take 6–12 weeks to process. Driving over a standard kerb without a proper crossover is a council offence and may invalidate your home insurance.

How to Maintain a Tarmac Driveway

Tarmac driveways require very little maintenance, but a small amount of regular care significantly extends their lifespan.

Annual Maintenance

Sweep the surface regularly to prevent moss and weed growth in small cracks. Pull any weeds that appear at the edges before they establish roots deep enough to lift the tarmac. In autumn, clear fallen leaves promptly — wet leaves left on tarmac through winter can cause staining and encourage moss.

Every 3–5 Years

Apply a tarmac restorer or sealer. This restores the black colour (UV light causes tarmac to fade to grey), fills micro-cracks and adds a protective layer against fuel spills and freeze-thaw damage. Most sealers are brush-on products that cost £25–£50 for a typical driveway.

Repairs

Fill cracks promptly with tarmac crack filler to prevent water getting underneath. Water under tarmac freezes in winter, expands and breaks the surface from below. Small potholes can be filled with cold-lay tarmac — clean out the hole, fill in 25mm layers, compact firmly.

Frequently Asked Questions

Best Tarmac Products UK 2026 — Our Top Picks

Whether you are filling a pothole or planning a full driveway project, here are the tools and materials we recommend for tarmac work in 2026.

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Where to Buy Tarmac in the UK

For small repairs, any builder’s merchant or DIY store stocks cold-lay tarmac in 25kg bags. For full driveway projects, you need hot-mix from a local asphalt plant — your contractor will arrange this.

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