How to Use the Asphalt Calculator
- Choose your units. USA mode gives tons (2,000 lb) and costs in dollars. UK mode gives tonnes (1,000 kg) and costs in pounds.
- Enter the area. Use length and width for a rectangle, or enter a known area for an irregular driveway. You can add a second area, such as a turning bay.
- Enter the compacted thickness. In UK mode, enter the binder (base) course and surface course separately, because they're different products priced differently.
- Add the stone base (optional). Enter the depth of crushed stone or MOT Type 1 sub-base to see how much to order.
- Enter prices per ton or tonne (optional), or an installed price per square foot or m² for a full-job estimate.
How to Calculate Asphalt Tonnage
Asphalt is ordered by weight, but you measure the job by volume, so the calculation has two steps:
- Volume = length × width × compacted thickness
- Weight = volume × density
Hot mix asphalt typically weighs about 145 pounds per cubic foot once compacted (roughly 142–148 lb/ft³), or about 2.32 tonnes per cubic metre. In US units:
Which simplifies to: tons ≈ square feet × thickness in inches × 0.00604.
In metric: tonnes = area (m²) × thickness (m) × 2.32. A quick rule: every square metre at 10mm thick needs about 23 kg of tarmac.
Always use the compacted thickness. Asphalt is laid loose and rolled down by about 20–25%, so to finish at 2 inches, the crew spreads about 2½ inches. The density figure above already accounts for this.
Worked example (USA): two-car driveway
A driveway 12 feet wide and 50 feet long, paved 3 inches thick on a 6-inch crushed stone base:
- Volume: 12 × 50 × 3 ÷ 12 = 150 cubic feet
- Asphalt: 150 × 145 = 21,750 lb = 10.9 tons
- Stone base: 12 × 50 × 0.5 ÷ 27 = 11.1 cubic yards; with 15% for compaction at 1.4 tons per yard = 17.9 tons
- At $150 per ton, the asphalt alone costs about $1,630. An installed driveway of this size typically runs about $4,200–$7,800 at $7–$13 per square foot.
Worked example (UK): 60 m² tarmac drive
A 60 m² drive built to a common domestic spec: 150mm MOT Type 1, 60mm binder course and 30mm surface course:
Installed, a drive like this typically costs about £55–£75 per m² for a standard full build, so roughly £3,300–£4,500.
How Thick Should an Asphalt Driveway Be?
| Use | USA asphalt (compacted) | USA stone base | UK surfacing | UK sub-base |
|---|---|---|---|---|
| Garden path, light foot traffic | 2 in | 4 in | 20–30mm surface on 40–50mm binder | 100mm |
| Residential driveway, cars | 2–3 in | 6–8 in (4 in on sandy soil, 8 in on clay) | 25–40mm surface on 50–60mm binder | 150mm |
| Cold climate or heavy vehicles (RV, van) | 3–4 in, or 4–6 in full depth | 8–10 in | 40mm surface on 60–80mm binder | 150–225mm |
| Small parking area | 3–4 in | 8 in | 40mm surface on 60mm binder | 200mm+ |
Binder vs surface course. Most driveways are laid in two layers. The binder (also called base course) is a coarser, stronger mix that carries the load. The surface (or wearing) course is a finer mix that gives a smooth, sealed finish. In the USA, a 3-inch residential drive is often 2 inches of base mix plus 1 inch of top. In the UK, common products are AC 20 dense binder and AC 6 or AC 10 dense surface.
The base matters more than the asphalt. Most driveway failures come from a weak or poorly drained base, not thin asphalt. Clay soils and wet sites need a deeper, well-compacted stone layer, and sometimes a geotextile membrane under it.
Asphalt and Tarmac Costs
USA
- Hot mix asphalt: typically $100–$200 per ton, delivered from the plant.
- Installed asphalt driveway: typically $7–$13 per square foot, with an average job around $4,000–$8,000.
- Sealcoating: about $500 per application, recommended every 2–3 years.
UK
- Overlay on a sound existing base: about £35–£55 per m².
- Standard full new installation: about £55–£75 per m².
- Premium build (deeper surface, SMA or coloured surfacing): about £75–£110 per m².
- Typical totals: a 30 m² parking pad costs about £1,800–£3,200; a 60 m² front drive about £2,700–£5,400.
Removing an old driveway, digging out soft ground, drainage, edging and dropped kerbs all add to the cost. A dropped kerb in the UK is arranged through your council and charged separately.
Asphalt vs Concrete vs Block Paving
| Asphalt / tarmac | Concrete | Block paving | |
|---|---|---|---|
| Upfront cost | Lowest | Higher | Highest |
| Lifespan | 12–20 years, or longer with maintenance | 25–40 years | 20–30+ years |
| Maintenance | Reseal every few years, fill cracks | Seal joints, low maintenance | Weed and re-sand joints |
| Repairs | Easy patching | Hard to patch invisibly | Lift and relay individual blocks |
| Climate | Flexes in freeze-thaw | Can crack in frost; needs joints | Flexible |
If you're comparing options, the Concrete Calculator works out the slab volume, and the Paving Slab Calculator covers pavers and slabs. The Cubic Yard Calculator handles gravel driveways.
Resurfacing vs Full Replacement
If your existing driveway has a sound, well-drained base with only surface wear, fine cracks or faded colour, an overlay (also called resurfacing) can save a lot of money. The contractor cleans the old surface, repairs any potholes, sprays a tack coat so the layers bond, and lays a new surface course, usually 1½–2 inches (30–40mm) thick. In the calculator, enter just the overlay thickness to see the tonnage.
A full replacement is needed when the driveway has deep cracks, sinking areas, standing water or "alligator" cracking, which all point to a failed base. Laying new asphalt over a failed base only hides the problem for a year or two. Overlays also raise the surface level, so check door thresholds, garage floors and drainage before choosing one.
Planning Rules for New Driveways (UK)
In England, you don't need planning permission for a new or replacement driveway in a front garden if it uses a permeable surface (such as porous asphalt, gravel or permeable block paving), or if rainwater drains to a lawn or border on your own property.
If the hard surface covers more than 5 m², is not permeable, and drains to the road or public sewer, you'll normally need planning permission. Contractors meet the rules by adding a drainage channel (often an ACO channel) that sends water to a soakaway or border, or by using porous asphalt. Wales, Scotland and Northern Ireland have similar but separate rules, so check with your council before work starts.
In the USA, driveway rules are set locally. Many cities require a permit for a new curb cut or driveway apron, and some limit how much of a front yard can be paved.
Tips for a Longer-Lasting Driveway
- Slope it. Aim for a fall of about 2% (¼ inch per foot, or roughly 1:50) so water runs off.
- Edge it. Unsupported asphalt edges crumble. Use kerbs, timber edging or a thickened edge.
- Lay it warm. Hot mix needs to be laid above about 5°C (40–50°F). Avoid the depths of winter.
- Keep heavy loads off for a few days while it cures, especially in hot weather.
- Seal and fill cracks early. Water in cracks freezes and opens them further.
Frequently Asked Questions
How do I calculate tons of asphalt?
Multiply length × width × compacted thickness (all in feet) to get cubic feet, multiply by 145 to get pounds, and divide by 2,000. A shortcut: square feet × thickness in inches × 0.00604.
How many tons of asphalt do I need for a driveway?
A 12 × 50 ft driveway at 3 inches thick needs about 10.9 tons. A 600 sq ft driveway at 2 inches needs about 7.3 tons.
How much does a ton of asphalt cover?
At 2 inches compacted, one ton covers about 83 square feet. At 3 inches, about 55 square feet.
How thick should a tarmac driveway be?
A common UK domestic build is 150mm of MOT Type 1, a 50–60mm binder course and a 25–40mm surface course, giving about 80–100mm of tarmac in total.
How much tarmac do I need per m²?
About 23 kg per m² for every 10mm of thickness. A 90mm two-layer drive needs about 209 kg (0.21 tonnes) per m².
What is the difference between asphalt and tarmac?
In everyday use, they mean the same thing: a mix of stone aggregate bound with bitumen. Tarmac originally used tar, which is no longer used, and the name stuck in the UK. Americans usually say asphalt or blacktop.
Do I need planning permission for a tarmac driveway?
In England, not if it's permeable or drains onto your own land. A non-permeable front driveway over 5 m² that drains to the road usually needs planning permission.
How much should I add for waste?
Add about 5% for uneven ground and edges. The calculator includes a waste allowance you can change.
Get quotes from local paving contractors
Base depth and drainage make or break a driveway. Get at least three quotes before you order material.