What this calculator does
Asphalt is bought by the tonne, so a plan area and a layer thickness have to be converted into a delivery quantity. This calculator does that conversion, applies a waste allowance, and turns the result into the number of tipper loads a site needs to order.
How to use it
- Enter the plan area and the compacted layer thickness.
- Set the density — 2.30–2.45 t/m³ is typical for asphalt surfacing; the exact value should come from the supplier.
- Add a waste allowance of 2–5 % for trimming and joins.
- Read the tonnage and the number of 20 t deliveries.
Governing formula
V = A · t ; m = V · ρ · (1 + w) Where:
-
A= Plan area [m²] -
t= Compacted thickness [m] -
ρ= Bulk density [t/m³] -
w= Waste fraction [–]
Worked example — 5,000 m² of 40 mm surfacing
The figures below were produced by running this page's own engine with the example inputs (Plan area (m²), Compacted thickness (mm), Bulk density (t/m³), Waste allowance (%)). If the calculator returns something different for the same numbers, that is a bug, not a rounding difference.
| Tonnage to order | 484.1 t |
|---|---|
| Compacted volume | 200 m³ |
| Tonnage before waste | 470 t |
| Deliveries (20 t) | 25 no |
| Assessment | 200.0 m³ compacted layer weighs ≈ 470.0 t (484.1 t with 3% waste) — plan ≈ 25 20-t deliveries. |
- Volume = 5,000 × 0.040 = 200 m³ compacted.
- At 2.35 t/m³ that is 470 t, or about 484 t with a 3 % waste allowance.
- That is 25 deliveries of 20 t — plan the site to receive them the same day.
Assumptions & limitations
Engineering calculation. Volume-to-weight conversion using an assumed bulk density. It does not include binder or additive content, and it uses the compacted thickness.
- Bulk density varies with mixture type, gradation and compaction level; confirm with the supplier.
- Structural layers must be ordered to a specified density and compaction, which this tool does not verify.
- Kerb, gusset and manhole areas are assumed to be in the gross plan area.
This tool supports professional engineering work; it does not replace a sealed design. Confirm every result against the applicable standard and a licensed engineer before it is built.
Schedule mode — paving areas
A paving order is built from a schedule of areas at different layer thicknesses — a base course, a binder course and a 40 mm surfacing are three different rows. Enter each once and the tonnage is the single order quantity.
The schedule totals are the sum of every item's own engine result, so they match running this calculator once per item. An item the engine rejects is reported in place and contributes nothing to the totals.
- A schedule that mixes layer types must list each layer as its own row; the engine does not know which layer is which.
References & standards
- EN 12697 series — bituminous mixtures, properties and test methods.
- Specification for Highway Works (UK) — pavement design and materials.
- MS-2 Mix Design Manual — Superpave volumetric mix design.