Asphalt Calculator

Short tons = length (ft) × width (ft) × depth (in) ÷ 12 × (1 + wastage) × 0.0283168 m³ per ft³ × 2,320 kg per m³ ÷ 907.18 kg per short ton

L

Length of the paved area, in feet — whatever unit you pick, the page converts to feet first

W

Width of the paved area, in feet

÷ 12

Inches in a foot, needed because paving depth is quoted in inches while the area is measured in feet

1 + waste

Wastage as a fraction — 5% is 1.05. It multiplies the volume exactly once, before the density, so the tonnage and the volume can never disagree

0.0283168

Cubic metres in a cubic foot, the step that puts the volume into the unit the density is quoted in

2,320

Density of compacted hot mix asphalt in kilograms per cubic metre — about 145 lb per ft³

907.18

Kilograms in a short ton: 2,000 lb. A metric tonne is 1,000 kg, so the same load is about 10% more short tons than tonnes

Use it when you are about to order the mix rather than when you are designing the pavement. It answers a single question — how many tons go on this area at this thickness — and it does that for a driveway, a car park, a yard or a patch. If you still have to work out the area, the square footage calculator takes the shape first and hands you a number this page can use, and the gravel driveway calculator does the same job for the stone underneath, which is bought by the cubic yard rather than by the ton. For an overlay on an existing surface, measure the area and pick the lift thickness the spec calls for; the page does not know whether the surface below is sound, and nothing here will tell you that it needs repairing.

1. A 40 × 12 ft driveway at two inches, with 5% wastage — the page's default

   1. Area: 40 × 12 = 480 ft²
   2. Depth in feet: 2 ÷ 12 = 0.16667 ft
   3. Geometric volume: 480 × 0.16667 = 80 ft³
   4. Add 5% wastage: 80 × 1.05 = 84 ft³
   5. Into cubic metres: 84 × 0.0283168 = 2.38 m³
   6. Weight: 2.38 × 2,320 = 5,518 kg
   7. In short tons: 5,518 ÷ 907.18 = 6.08; in tonnes: 5,518 ÷ 1,000 = 5.52

   Six tons is the number the plant wants, and it is a small load — half a truck, so expect a minimum charge or a delivery that shares the wagon. The 3.11 cubic yards beside it is the same material described the other way, and it is there so you can check the number against a supplier who does quote by volume. Both come from the same eighty-four cubic feet, so 6.08 tons and 3.11 cubic yards are two spellings of one quantity rather than two independent answers.

2. The same driveway with no wastage allowed for

   1. Geometric volume: 80 ft³, unchanged — wastage is the only thing that moved
   2. Into cubic metres: 80 × 0.0283168 = 2.27 m³
   3. Weight: 2.27 × 2,320 = 5,255 kg
   4. In short tons: 5,255 ÷ 907.18 = 5.79; in tonnes: 5.26

   Setting wastage to zero is a legitimate choice, not an empty form: it is what you want if you have measured a figure you trust and intend to order exactly to it. Compare the two examples and the allowance is visible — 5.79 × 1.05 = 6.08 — which is the whole reason it multiplies the volume once rather than being applied to the tonnage at the end. Ordering the strict geometric quantity is how most shortfalls happen, because the paver lays a little wider than you measured and the edges always take more.

3. A 100 × 20 ft car park corner at one inch, an overlay with no wastage

   1. Area: 100 × 20 = 2,000 ft²
   2. Depth in feet: 1 ÷ 12 = 0.08333 ft
   3. Volume: 2,000 × 0.08333 = 166.67 ft³
   4. Into cubic metres: 166.67 × 0.0283168 = 4.72 m³
   5. Weight: 4.72 × 2,320 = 10,950 kg
   6. In short tons: 10,950 ÷ 907.18 = 12.07; in tonnes: 10.95

   This area and thickness is the same volume as 1,000 square feet at two inches — 2,000 × 1 and 1,000 × 2 are both 2,000 square foot inches — and it returns the same 12.07 short tons the reference table gives for that row. Two different jobs, one quantity. A one inch lift is a thin overlay rather than a structural course, so it is the thickness to use when you are refreshing a surface that is still sound.

The density is the one figure the whole answer rests on, and it is an estimate: 2,320 kilograms per cubic metre is a typical value for a compacted dense-graded surface course, and the mix design, the aggregate, the bitumen content and how well it was rolled all move it. A coarse base course, a stone mastic or a rubber-modified mix can sit outside it by a few percent, which on a twenty ton order is most of a ton. The wastage allowance is a judgement rather than a measurement too: five percent suits a straightforward rectangle, and irregular shapes, many manholes, or paving against a kerb on both sides take more. The page also assumes the whole area is paved to one thickness — if you are feathering into an existing surface at the edges, or the sub-base is out of level enough that the lift varies, the real tonnage follows the average thickness rather than the nominal one. Nothing here covers the design of the pavement: thicknesses are inputs, so the page will happily price a two inch lift on a sub-base that cannot carry the traffic. And it is a materials quantity, not a cost — the price of the mix, the haul and the laying are all separate.

How many tons of asphalt do I need for a driveway?

About 0.00603 short tons per square foot per inch of thickness, so a 480 square foot driveway at two inches takes 6.08 tons with a 5% allowance. The arithmetic behind that figure: a square foot of compacted hot mix one inch thick weighs 145 ÷ 12, or roughly 12 pounds, and there are 2,000 pounds in a short ton. A cubic yard of the mix is a shade under two tons, which is the other handy anchor — most single driveways land between three and fifteen tons.

How thick should an asphalt driveway be?

Two inches of surface course over four to six inches of compacted base is the usual residential build, and three inches of surface on a heavier base for anything a delivery truck will use. This page does not choose the thickness for you, because it depends on the sub-base and the traffic rather than on the area: paving thickness is a design decision, and getting it wrong is expensive to undo. If you are unsure, the thickness you are replacing is a reasonable starting point, and a local contractor will know what the ground under you needs.

What is the difference between a short ton and a tonne?

92.82 kilograms. A metric tonne is 1,000 kg, while a short ton is 2,000 lb or 907.18 kg, so the same load is about 10% more short tons than tonnes — 6.08 against 5.52 in the first example. Both outputs are on the page because a US mix plant tickets in short tons while most of the rest of the world quotes tonnes, and reading one as the other is a tenth of the load. When a quote or a ticket just says tons, check which one before comparing prices.

How much wastage should I allow for asphalt?

Five percent is a good default for a simple rectangle, and there is a case for leaving it at zero if you have a measured figure you trust. Add more for a complicated shape, for paving around several manholes or drains, or where the paver has to lay against a kerb on both sides — the material that goes into those details is real but easy to leave out of the area you measured. The allowance is not only about spillage: it also absorbs the difference between loose and compacted material and the small variation in the depth actually achieved.

Does this work for a gravel driveway or a base course?

The arithmetic does, but the density does not. 2,320 kilograms per cubic metre is a compacted asphalt surface, and crushed stone aggregate is lighter and is sold by the cubic yard rather than by the ton, so the gravel driveway calculator and the gravel calculator are the right pages for the base underneath. A common build is four to six inches of stone under two inches of asphalt, which means both pages have a job to do on the same driveway, and neither one covers the other's layer.

How accurate is the tonnage?

Within a few percent for ordering, and not a certified quantity. The density varies with the mix design, the aggregate and the bitumen content, and the depth you actually achieve varies with the level of the sub-base, so a real delivery can come in slightly over or under the figure here. Ordering a little over is normal practice and cheap next to a second delivery of a short load, which is why the wastage field is there and defaults to five rather than to nothing.

• Approximate Conversions from U.S. Customary Measures to Metric — the chart behind the pound, short ton, cubic foot and cubic yard figures used here — National Institute of Standards and Technology
• The International System of Units (SI) brochure — the kilogram and the tonne, the two mass units the tonnage is reported in — Bureau International des Poids et Mesures (BIPM)