Free calculator · no sign-up
Tarmac calculator: how many tonnes do you need?
Enter the area and the layer depths. You get binder course tonnes, surface course tonnes, sub-base tonnage and how many delivery loads the job needs — with the arithmetic written out so you can check it.
Area
40 m²
Tarmac to order
8.69 t
Binder + surface, including 5% waste
- Binder course (60 mm)
- 5.8 t
- Surface course (30 mm)
- 2.9 t
- Sub-base (150 mm)
- 13.23 t
- Loads at 5 t
- 2
No tarmac price is shown because hot-lay rates are quoted locally. Type your merchant's £/tonne to cost it.
How the numbers are worked out
- Area = 8 m × 5 m = 40 m²
- Binder: 40 m² × 60 mm = 2.4 m³ compacted · × 5% waste = 2.52 m³ to order · × 2.3 t/m³ = 5.8 t
- Surface: 40 m² × 30 mm = 1.2 m³ compacted · × 5% waste = 1.26 m³ to order · × 2.3 t/m³ = 2.9 t
- Sub-base: 40 m² × 150 mm = 6 m³ · × 5% waste · × 2.1 t/m³ = 13.23 t
- Total tarmac = 8.69 t · loads = 2 at 5 t
Tonnages are compacted volumes × density, with waste added to the order quantity. Excavation, membrane, kerbs, drainage, tack coat, labour, plant and disposal are not in this page — they are all in the full app.
Small patches and repairs
Below about a tonne, hot-lay delivery rarely makes sense. Bagged drive-repair macadam is the usual answer — the price book carries Heidelberg Drive Repair Asphalt Macadam 6 mm 25 kg at £13.95 a bag from Myers (checked 9 October 2026), labelled repair material, not a substitute for a hot-lay surface course.
Drainage and planning
Tarmac is impermeable, so the surface must fall away from buildings and drain to a permeable area or a proper drainage channel. In England, new front-garden hard surfacing over about 5 m² generally needs planning permission unless it is permeable or drains to a permeable area. Check with your local planning authority — this is general guidance only.
Turn this into a proper driveway quote
Driveway Quote does the whole build-up — excavation and spoil, sub-base, membrane, tack coat, kerbs, drainage, labour, plant, disposal, your margin and VAT — and sends the customer a clean quote with your costs hidden.
Tarmac calculator questions
- How many tonnes of tarmac do I need for a driveway?
- Work out the area in square metres, multiply by each layer's depth in metres to get a volume, then multiply by the compacted density. Hot-lay asphalt compacted to around 2.3 tonnes per cubic metre is the usual working figure, so a 40 m² driveway with 60 mm of binder course needs about 40 × 0.060 × 2.3 = 5.5 tonnes before waste.
- What depths should I use for binder and surface course?
- A domestic driveway is commonly built with 40–60 mm of AC20 binder course over a compacted sub-base, topped with 20–40 mm of AC10 surface course. This calculator defaults to 60 mm binder and 30 mm surface, and both are editable.
- How much waste should I allow?
- Around 5% is a sensible starting point for a straightforward rectangular drive; allow more for narrow strips, bays, radii and cuts where material is lost off the saw or the shovel. The calculator adds waste to the order quantity, not to the finished compacted volume.
- Is there a minimum load for hot-lay tarmac?
- Usually yes. Hot-lay asphalt is delivered from the plant in loads, and most merchants apply a minimum load or a part-load surcharge, so a small patch can cost far more per tonne than a full drive. Set your supplier's minimum load here to see how many loads your job needs.
- Why doesn't the calculator show a tarmac price?
- Hot-lay asphalt is priced locally and moves with the plant, the haul and the load size, so any single UK price we printed would be a guess. Enter your merchant's £ per tonne and the calculator will cost the tonnage for you — we never publish an invented rate.
- Does a tarmac driveway need planning permission?
- In England, new hard surfacing of a front garden over about 5 m² generally needs planning permission unless the surface is permeable, or the water is directed to a permeable area such as a lawn or border. Tarmac is impermeable, so check the arrangement with your local planning authority. This is general guidance, not legal advice.