Driveway & Hard Paving
Asphalt / Tarmac Calculator
Estimates tonnes of asphalt or tarmac for driveways
Updated 28 May 2026 · Live
What this tool does
Estimates tonnes of asphalt or tarmac for driveways.
Formula Used
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How the asphalt / tarmac calculator works
Multiply area by laid (compacted) depth to get volume, then multiply volume by the compacted density of the mix to get tonnes. Multiply tonnes by the supplier rate per tonne for an indicative cost. Every figure is an estimate — site conditions and the specific mix design will move the final number.
Typical UK asphalt depths and densities
Residential driveways are commonly laid as a 50–65 mm binder course (asphalt concrete) with a 20–40 mm surface course on top, all bedded on a sub-base. Hot-rolled asphalt and dense bituminous mixes typically have a compacted density of 2.30–2.45 t/m³; open-graded mixes sit lower. Your supplier will quote the specific density for the mix you order — adjust the density input accordingly.
What this tool does not do
It does not size the sub-base, factor edge restraint, replace a professional quote, assess structural adequacy for vehicle loads, or confirm Building Regulations compliance. Those remain the responsibility of a suitably qualified designer, surveyor, or your building control officer.
Planning permission and SUDS
Impermeable paving over 5 m² between a house and the public highway needs planning permission unless surface water drains to a permeable area within the curtilage (a SUDS-compliant solution under the 2008 regulation change). Permeable surfaces are normally exempt. Confirm the position for your address with the local planning authority.
Drainage and Building Regulations
Surface water from a drive must not run onto the public highway. Approved Document H and local bylaws require drainage to soakaway, permeable joints, or attenuation. A pre-application enquiry to the local authority can give early clarity, which tends to be less costly than retrospective correction.
Before you order
Cross-check the calculator's output against a supplier quote — pricing assumptions, mix specification and density vary between suppliers. Ask for the specific product (for example AC 10 surf or AC 20 dense bin under BS EN 13108), the compacted density the supplier assumes, and confirm delivery and laying timescales against your programme.
Adjusting the defaults
Every input in this calculator is editable. Enter your own area, depth, density and price — the output recalculates instantly. If the defaults feel off for your project, your own numbers always override them.
Using this asphalt / tarmac calculator alongside other BuildMetricLab tools
This calculator works best as part of a planning workflow. Pair the tonnage with our sub-base, edging, and material-cost calculators to build a complete driveway estimate. All BuildMetricLab tools run entirely in your browser — no sign-up, no data sent anywhere, and every formula is shown on-page so you can audit the maths.
Sources & methodology
Tonnes = Area (m²) × Compacted depth (m) × Compacted density (t/m³). Defaults assume a typical UK driveway specification of 50 mm at 2.40 t/m³; every input is editable. Indicative cost = tonnes × price per tonne.
Frequently asked questions
Are asphalt / tarmac calculator results accurate enough to order materials?
Use them as a starting estimate only. Verifying the final quantity with your supplier or contractor before ordering is good practice — the specific mix density, site conditions and edge cuts all affect the true figure.
What compacted density should I use?
Dense bituminous and hot-rolled asphalt mixes are typically 2.30–2.45 t/m³ once compacted. The calculator defaults to 2.40 t/m³, which suits most UK driveway specifications. Your supplier will confirm the figure for the specific mix you order — enter that value for the closest estimate.
Does this replace professional advice?
No. This tool is a planning estimator. For works that affect structure, Building Regulations, Party Wall, gas, electrics, drainage to a sewer, or similar, consult a suitably qualified professional.
Can I change the unit prices?
Yes — every price field is editable. Plug in your supplier's quote to get a total that matches your project.
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