Tarmac Calculator — Tonnes, Cost and Coverage for UK Driveways
Free UK tarmac calculator. Enter length, width and depth in metres for tonnage, m³ and cost in £. AC, HRA, SMA and planings densities included.
Calculator
Enter the dimensions of the area you are surfacing and this calculator returns the area, the volume in cubic metres, the weight, the tonnage to order and an estimated cost in GBP. It is set up for the United Kingdom: metric units by default, the mix designations used under BS EN 13108 and BS 594987, and local pricing.
Quick answers
A 50 m² driveway at 50 mm needs about 5.9 tonnes of AC surface course, or 6.5 tonnes with a 10% allowance.
| Area | 40 mm | 50 mm | 60 mm | 80 mm | 100 mm |
|---|---|---|---|---|---|
| 25 m² | 2.4 t | 2.9 t | 3.5 t | 4.7 t | 5.9 t |
| 50 m² | 4.7 t | 5.9 t | 7.0 t | 9.4 t | 11.8 t |
| 100 m² | 9.4 t | 11.8 t | 14.1 t | 18.8 t | 23.5 t |
| 200 m² | 18.8 t | 23.5 t | 28.2 t | 37.6 t | 47.0 t |
| 500 m² | 47.0 t | 58.8 t | 70.5 t | 94.0 t | 117.5 t |
| 1,000 m² | 94.0 t | 117.5 t | 141.0 t | 188.0 t | 235.0 t |
| 5,000 m² | 470.0 t | 587.5 t | 705.0 t | 940.0 t | 1,175.0 t |
| 7,300 m² | 686.2 t | 857.8 t | 1,029.3 t | 1,372.4 t | 1,715.5 t |
The tonnage formula
Weight (kg) = Volume (m³) × Density (kg/m³)
Tonnes = Weight (kg) ÷ 1,000
Combined: Tonnes = Area (m²) × Thickness (m) × 2.35
Worked example — a 240 m² area at 50 mm compacted:
- Volume: 240 × 0.05 = 12 m³
- Weight: 12 × 2,350 = 28,200 kg
- Tonnage: 28.2 tonnes
- With a 10% allowance: 31.0 tonnes to order
Density by mix type
UK dense asphalt concrete runs 2,320–2,400 kg/m³; hot rolled asphalt is slightly lighter at about 2,290 kg/m³.
| Designation | Description | Density (kg/m³) | Typical use | Standard |
|---|---|---|---|---|
| AC 10 surf | Asphalt concrete surface course, 10 mm | 2,340 | Surface course 25–40 mm | BS EN 13108-1 |
| AC 14 surf | Asphalt concrete surface course, 14 mm | 2,350 | Surface course 40–50 mm | BS EN 13108-1 |
| HRA 30/14 | Hot rolled asphalt with pre-coated chippings | 2,290 | Traditional surface course | BS EN 13108-4 |
| SMA 10 surf | Stone mastic asphalt | 2,400 | High-traffic surface course | BS EN 13108-5 |
| Thin surface course system | Proprietary thin surfacing | 2,320 | Surface course 20–40 mm | BS EN 13108-2 |
| AC 20 bin | Asphalt concrete binder course, 20 mm | 2,360 | Binder course 50–80 mm | BS EN 13108-1 |
| AC 32 base | Asphalt concrete base, 32 mm | 2,370 | Base 80–150 mm | BS EN 13108-1 |
| EME2 | High-modulus base | 2,435 | Heavy-duty base | BS EN 13108-1 / CD 226 |
| Porous asphalt | PA 20 | 2,000 | Drainage surface course | BS EN 13108-7 |
| Recycled planings | Reclaimed asphalt planings | 2,000 | Drives, hardstanding, sub-base | BS EN 13108-8 |
| Type 1 sub-base | Granular sub-base | 2,100 | Unbound sub-base 100–300 mm | SHW Clause 803 |
| Bitumen 40/60 | Paving grade binder | 1,030 | Tack coat and binder only | BS EN 12591 |
Coverage per tonne
| Compacted thickness | m² per tonne | tonnes per 100 m² | tonnes per 1,000 m² |
|---|---|---|---|
| 20 mm | 21.3 | 4.70 | 47.0 |
| 25 mm | 17.0 | 5.88 | 58.8 |
| 30 mm | 14.2 | 7.05 | 70.5 |
| 40 mm | 10.6 | 9.40 | 94.0 |
| 50 mm | 8.5 | 11.75 | 117.5 |
| 60 mm | 7.1 | 14.10 | 141.0 |
| 70 mm | 6.1 | 16.45 | 164.5 |
| 80 mm | 5.3 | 18.80 | 188.0 |
| 100 mm | 4.3 | 23.50 | 235.0 |
| 150 mm | 2.8 | 35.25 | 352.5 |
| 200 mm | 2.1 | 47.00 | 470.0 |
Recommended thickness
| Application | Surface course | Binder / base course | Unbound base |
|---|---|---|---|
| Footpath | 20–30 mm surface | — | 100 mm Type 1 |
| Domestic driveway, cars | 20–25 mm surface | 50–60 mm binder | 100–150 mm Type 1 |
| Driveway, vans or caravan | 25 mm surface | 60–70 mm binder | 150–200 mm Type 1 |
| Private car park | 30 mm surface | 60 mm binder | 200 mm Type 1 |
| Commercial car park | 40 mm surface | 60–80 mm binder | 225–300 mm Type 1 |
| HGV yard | 40 mm surface | 100–150 mm binder and base | 300–450 mm Type 1 |
| Estate road (adoptable) | 40 mm surface | 60 mm binder + 100 mm base | 225 mm Type 1 |
| Trunk road | 40–50 mm surface | 60 mm binder + 150–250 mm base | Capping as designed |
2026 prices
| Item | Low | Typical | High |
|---|---|---|---|
| AC surface course per tonne | £72 | £88 | £115 |
| HRA per tonne | £82 | £100 | £128 |
| SMA per tonne | £95 | £118 | £150 |
| Binder course per tonne | £62 | £76 | £98 |
| Base course per tonne | £56 | £70 | £90 |
| Recycled planings per tonne | £8 | £18 | £32 |
| Type 1 sub-base per tonne | £12 | £18 | £28 |
| Bitumen 40/60 per tonne | £490 | £525 | £560 |
| Driveway installed per m² | £45 | £65 | £90 |
| Car park installed per m² | £35 | £50 | £72 |
Price by region
| Region | Material | Installed |
|---|---|---|
| London | £95 – £128 / tonne | £60 – £110 / m² installed |
| South East | £88 – £118 / tonne | £55 – £98 / m² |
| South West | £82 – £110 / tonne | £48 – £88 / m² |
| East of England | £82 – £112 / tonne | £48 – £88 / m² |
| Midlands | £76 – £104 / tonne | £45 – £82 / m² |
| North West | £74 – £102 / tonne | £44 – £80 / m² |
| Yorkshire & Humber | £72 – £100 / tonne | £43 – £78 / m² |
| North East | £70 – £98 / tonne | £42 – £76 / m² |
| Wales | £76 – £106 / tonne | £45 – £84 / m² |
| Scotland | £78 – £110 / tonne | £46 – £88 / m² |
| Northern Ireland | £74 – £102 / tonne | £44 – £80 / m² |
Waste and compaction allowance
Loose material behind the paver occupies about 20% more volume than the compacted surface. Add edge trimming, material left in the lorry and normal measurement tolerance, and a 10% allowance is standard.
- 5% — simple machine-laid rectangle, experienced crew
- 10% — standard driveway or car park
- 15% — curved edges, several sections, hand-laid work
- 15–20% — recycled planings and cold-laid material
- 20–25% — unbound granular base
Common mistakes
- Using the loose thickness instead of the compacted design thickness.
- Failing to convert millimetres to metres before multiplying.
- Applying one density to every mix type.
- Measuring the excavation rather than the finished surface.
- Calculating a multi-layer structure as a single combined thickness.
- Forgetting the unbound base, which is often the larger tonnage.
- Not checking the plant's minimum order and small-load surcharge.
- Rounding down. A short order means a cold joint and a second mobilisation.
Measuring the site
Split the site into rectangles, triangles, circles and trapezoids and enter each as a separate area. Measure every dimension at three points and use the largest — surfaced areas are rarely as regular as they look. For a circular turning area, measure the diameter at the widest point and let the calculator apply π × r².
On a slope the true surface area exceeds the plan area. At a 10% gradient the difference is only 0.5% and can be ignored. Above 20%, multiply the length by √(1 + gradient²).
Frequently asked questions
How much tarmac do I need?
Multiply the area in square metres by the compacted thickness in metres, then by 2.35. A 100 m² area at 50 mm needs about 11.8 tonnes, or 12.9 tonnes with a 10% allowance.
What is the density of tarmac?
UK dense asphalt concrete runs 2,320–2,400 kg/m³; hot rolled asphalt is slightly lighter at about 2,290 kg/m³. The calculator uses 2,350 kg/m³ by default and lets you select any of the 12 mixes listed on this page.
How much does tarmac cost per tonne?
Around £72 to £115 in 2026, with £88 typical. Distance from the plant is the largest single factor.
How many square metres does a tonne cover?
About 8.5 m² at 50 mm compacted, 10.6 m² at 40 mm and 5.3 m² at 80 mm.
How many cubic metres is one tonne?
0.426 m³ at 2,350 kg/m³. The calculation is 1,000 ÷ density.
How thick should the surfacing be?
See the thickness table on this page. Domestic access typically takes a 20–25 mm surface over 100–150 mm Type 1; commercial and adopted work is considerably heavier and follows BS EN 13108 and BS 594987.
What allowance should I add?
10% for standard work, 5% for a simple machine-laid rectangle, 15% for curved or hand-laid areas and 15–20% for recycled material.
Which standards apply?
Work in the United Kingdom follows BS EN 13108 and BS 594987, administered by National Highways and the Specification for Highway Works.