Bitumen Calculator: Estimate Gallons for Sealing and Tack Coats

What Is Bitumen, and How Is It Different From Asphalt

Bitumen is the sticky, black liquid binder made from crude oil that holds asphalt together. Asphalt itself is the finished paving material, bitumen mixed with sand, gravel, and crushed stone. People often use the two words interchangeably, especially outside the United States where bitumen is the more common term, but bitumen is really just one ingredient in the finished product. It is also sometimes called liquid asphalt, particularly when it is being applied on its own rather than as part of a hot mix.

This calculator handles the situations where bitumen is applied on its own as a liquid, sealing an existing driveway, bonding a tack coat between pavement layers, priming a base before paving, or spraying a surface treatment. Each of these uses a different application rate, which is exactly why the calculator lets you pick your project type before it runs the numbers.

Bitumen Driveway Sealing: How Much You Need

Sealing a bitumen or asphalt driveway typically uses about 0.12 gallons of sealer per square yard for a single coat. A standard two car driveway, roughly 800 square feet, comes out to around 89 square yards, which works out to roughly 10 to 11 gallons of sealer for one coat.

Most driveways hold up better with two coats rather than one, particularly if the surface has not been sealed in a few years, so double your gallon figure if you are planning a two coat application.

Tack Coats, Prime Coats, and Surface Treatments Explained

If you are working on a larger paving project rather than a homeowner driveway, the application rate changes significantly depending on what the bitumen layer is actually doing.

Tack coats are a thin bitumen layer sprayed onto an existing surface before a new asphalt layer goes on top, helping the two layers bond. Because it only needs to coat the surface, not saturate it, tack coats use a light rate, typically around 0.08 gallons per square yard.

Prime coats go onto a raw gravel base before the first asphalt layer, soaking into the base material to bind loose particles and reduce moisture penetration. Because it needs to penetrate rather than just coat, prime coats use a much heavier rate, often around 0.30 gallons per square yard.

Surface treatments, sometimes called chip seals, spray a bitumen layer directly onto a surface followed by an aggregate chip layer, commonly used on rural roads and low traffic pavement as a lower cost alternative to a full asphalt overlay. These typically run around 0.20 gallons per square yard.

Bitumen Calculator Math Explained

Unlike the asphalt or gravel calculators on this site, which work by weight and tonnage, this calculator works by liquid coverage rate, since bitumen used on its own is applied as a spray rather than measured by tons. The formula converts your area from square feet to square yards, then multiplies by the gallons per square yard rate for your chosen application type, plus your waste allowance for overspray and uneven surface absorption.

If you are figuring the asphalt itself rather than a liquid bitumen application, our asphalt tonnage calculator uses the tonnage based formula instead, and our gravel calculator handles the base material underneath.

Frequently Asked Questions

Is asphalt the same as bitumen?
Not exactly. Bitumen is the sticky black liquid binder made from crude oil, while asphalt is the finished paving material made by mixing bitumen with sand, gravel, and stone. Bitumen is sometimes called liquid asphalt.

How much bitumen do I need to seal a driveway?
A typical driveway sealcoat uses around 0.12 gallons of bitumen sealer per square yard for a single coat. Measure your driveway's length and width, then run those numbers through the calculator above to get an exact gallon figure.

What is a tack coat and how much bitumen does it need?
A tack coat is a thin bitumen layer sprayed between an existing surface and a new asphalt layer to help them bond. It uses a much lighter application rate than sealcoating, typically around 0.08 gallons per square yard.