Asphalt Tonnage Calculator: How Much Asphalt Do You Actually Need

How to use this tool

Pick the shape, type the length and width, or the diameter for a circle such as a cul de sac, and choose the unit you measured in. Then give the compacted thickness. The answer appears as you type: tons and cubic yards at the top, pounds per square yard and the cost in the coloured cards, and every other unit further down, including tons per lane mile and truckloads.

The density box is filled in for you at 145 pounds per cubic foot, the usual figure for compacted hot mix. If your plant gives you the density of the mix you are buying, type it over the top and the whole page uses it. The density list also offers the Asphalt Institute figures and the one Washington State DOT uses for its quantity tables, and the chart below the results shows the same job at all of them, so you can see how much the choice matters before you order.

Add a price per ton and the page works out the mix cost, the cost per square foot and the cost per square yard. The tons per truck box sets how the truckload count is worked out; change it to whatever your hauler actually carries.

Why tonnage, not just volume

I have stood on enough job sites to know how this usually goes. Someone measures a driveway or a stretch of road, calls the supplier, and either orders too little, which means a delayed truck run in the middle of the job and nobody is happy about that, or orders too much, which means paying for asphalt that ends up sitting in a pile doing nothing. Getting the tonnage right the first time saves money and saves a headache.

Asphalt is sold by weight, not by volume, which trips people up if they are used to thinking in cubic yards the way you might for concrete or gravel. The plant weighs every truck over a scale, so the ton is the unit on the ticket. The conversion from the size of the job runs through density: how many pounds a cubic foot of compacted mix weighs.

What the calculation is doing

Volume is plain geometry. A 12 by 40 foot driveway is 480 square feet, and 3 inches is a quarter of a foot, so the finished mat is 120 cubic feet. At 145 pounds per cubic foot that weighs 17,400 pounds, and dividing by 2,000 gives 8.7 tons. Add 5 percent and the order is 18,270 pounds, which is 9.135 tons.

The thickness in that sum is the compacted thickness, the depth of the finished mat after rolling. That is the number a specification or a quote gives, and it is the one the calculator wants.

Where the density figures come from

Compacted hot mix asphalt typically weighs around 145 pounds per cubic foot, though it varies with the mix design, the aggregate and how well it is compacted on site. The Asphalt Institute puts compacted mix in a range of 142 to 148 pounds per cubic foot and suggests using 148 when working out tonnage. Washington State DOT sizes its paving quantities at 137 pounds per square yard for every 0.10 foot of compacted depth, which works out to 2.05 tons per cubic yard, about 152 pounds per cubic foot.

The rule of about 110 pounds per square yard per inch comes from the middle of that range: a square yard one inch thick is three quarters of a cubic foot, and three quarters of 145 is 108.75. It is a good rule for a quick check on a quote.

In place densities of compacted hot mix. Every row opens the tons and cubic yards converter at that density.

From the lightest of those figures to the heaviest is about 7 percent. On a small driveway that is a few hundred pounds; on a parking lot or a stretch of road it is several truckloads. If your supplier can give you the density of their mix, use it instead of the default.

The math, step by step

Here is a worked example you can repeat on paper. Say you are paving a driveway 100 feet long and 20 feet wide at a compacted thickness of 2 inches.

First, the area: 100 feet times 20 feet is 2,000 square feet. Next, the thickness in feet, since the area is in square feet: 2 inches is 2 divided by 12, a sixth of a foot. Area times thickness is the volume: 2,000 times one sixth is 333.33 cubic feet. At 145 pounds per cubic foot that is 48,333 pounds, and dividing by 2,000 gives 24.17 tons. With 5 percent extra it comes to 25.38 tons, a little over one truckload at 20 tons.

Keep the thickness as a fraction of a foot rather than rounding it to 0.167 early. On a big job, rounding the thickness first moves the answer by more than you would expect.

Tons per square yard and per lane mile

Road and parking work is usually priced by the square yard, and highway work by the lane mile. The same density figure turns either into tons.

At 145 pounds per cubic foot, a 12 foot lane and no allowance for waste. Each thickness opens the calculator on a 12 by 40 foot driveway at that depth.

Why you should add a little extra

Nobody gets 100 percent material efficiency on a real job site. Some asphalt sticks to the truck bed, some is left in the paver, the edges and the tapers at the ends never use material as neatly as a rectangle on paper, and the ground under a new mat is never perfectly level. Most contractors build in somewhere between 5 and 10 percent extra to cover this.

The calculator starts at 5 percent. On a simple rectangle with an experienced crew that is usually enough. If the shape is irregular, or it is a small job where a few hundred pounds is a bigger share of the whole, push it toward 10.

Common thickness guidelines

People often ask how thick their asphalt needs to be, and the honest answer is that it depends on what the surface has to carry. These are the thicknesses most guidance settles on.

General guidelines, not engineering specifications. Local frost, soil and traffic decide the real answer.

A thick section is not laid in one go. Each lift is rolled while it is hot, and a lift that is too thick for the mix will not compact properly, so a 4 inch section is usually a base course and a surface course. The tonnage is the same either way. For anything load bearing or code regulated, check the local requirements or get a proper design from an engineer rather than guessing.

Mistakes that throw off the numbers

Using the loose thickness instead of the compacted thickness. Hot mix goes down loose behind the paver, roughly a quarter thicker than it ends up, and is rolled down to the finished thickness. If someone tells you a lift thickness before compaction, it is not the number to use here.

Averaging an odd shape into one length and width. If the area is not a simple rectangle, split it into rectangles and circles, work each one out and add the tonnage together.

Ignoring the base. An asphalt driveway is only as good as the compacted gravel under it. Three inches of mix over a soft or thin base will crack in a season, however carefully the tonnage was worked out.

Using a generic density for an unusual mix. Most jobs are fine at 145, but a specialty or unusually dense mix can be several percent heavier. Ask for the figure.

Skipping the allowance to make a number look better on paper. It rarely works out that cleanly on the actual job.

Who this calculator is useful for

• Contractors and estimators putting together a material order or a quote for a client.
• Homeowners with a driveway quote in hand who want a sanity check on what a contractor is proposing.
• Property managers budgeting for parking lot resurfacing across a season.
• Anyone comparing supplier prices who wants the real cost of the job, not just the cost per ton.

Popular calculations

Each opens the calculator on that size, thickness and density with its own address, and every value can be changed once it is open.

Driveways at 3 inches

Driveways at 2 and 4 inches

Overlays

Parking lots

Roads and lane miles

Cul de sacs and circles

By square yards

Tons and cubic yards of asphalt

At other densities

Metric

How this was checked

The engine was written and tested in Node before it went near the page, against hand calculations in every unit: the 12 by 40 foot driveway above, the 100 by 20 foot example, an 80 foot cul de sac, which comes to 95.66 tons at 3 inches with 5 percent extra, and a 5 by 10 metre area at 50 millimetres. The density figures were checked against their own sources: the Asphalt Institute worked example of 83.3 cubic feet at 148 pounds per cubic foot comes to 6.16 tons, and the WSDOT figure of 137 pounds per square yard per 0.10 foot is exactly 2.055 tons per cubic yard. A 12 foot lane mile at 2 inches works out by hand to 765.6 tons, which is what the page shows.

Every address in the lists above was then opened and checked for a distinct title, the right answer, charts that render, and clean CSV, image and print output containing only that calculation, at desktop, tablet and phone widths.

Common questions

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

For a single car driveway of 12 by 40 feet at 3 inches compacted, about 8.7 tons at 145 pounds per cubic foot, or 9.13 tons with 5 percent extra. A two car driveway of 20 by 40 feet at the same thickness takes about 15.2 tons. Put your own length, width and thickness into the calculator; the answer moves in a straight line with each of them.

How much area does a ton of asphalt cover?

At 145 pounds per cubic foot, one ton covers about 110 square feet at 1.5 inches, 83 square feet at 2 inches, 55 at 3 inches and 41 at 4 inches. Double the thickness and you halve the coverage.

How many tons are in a cubic yard of asphalt?

About 1.96 tons of compacted hot mix at 145 pounds per cubic foot, and anywhere from 1.92 to 2.05 across the densities in common use. Turned around, a ton is about 0.511 of a cubic yard.

How much does asphalt weigh per square yard?

About 110 pounds per square yard for every inch of compacted thickness, which is where the common rule comes from. At 145 pounds per cubic foot the exact figure is 108.75 pounds, so 2 inches is about 218 pounds per square yard and 3 inches about 326.

How many tons of asphalt are in a lane mile?

A 12 foot lane one mile long takes about 766 tons at 2 inches compacted and 145 pounds per cubic foot, 574 tons at 1.5 inches and 1,148 tons at 3 inches, before any allowance for tapers, widening or waste.

How thick should an asphalt driveway be?

As a general starting point, an overlay on an existing driveway runs 1.5 to 2 inches, a new driveway 3 to 4 inches over a properly compacted gravel base, and areas carrying trucks or regular heavy traffic 4 inches or more, laid in more than one lift. Those are guidelines rather than a pavement design; the ground, the climate and the loads decide the real answer.

Related Calculators and Reference

• Gravel calculator: for the compacted base that goes down first.
• Unit weight of asphalt: the unit weight the tonnage is calculated from.
• Excavation cut and fill calculator: for the earthworks underneath the pavement.
• Earthworks volume calculator: when the area comes off a survey grid rather than a drawing.
• Square footage calculator: for irregular areas before you bring the thickness in.
• FHWA Pavements: federal pavement guidance on mix and layer design.