Are you planning a large painting job, such as the interior or exterior of your home, a fence surrounding your yard or even something bigger? O
A gallon of paint weighs between 6 and 12 pounds dependent on the type of paint being used. Latex, oil-based, acrylic, and enamel paints will all have different densities and weights. The weight of the paint may be important to know if you plan on transporting it prior to painting.
Let’s take a closer look at the different types of paint and varying factors as these numbers will be drastically different.
Since paint is traditionally measured in gallons, knowing the weight of each gallon of paint will give you the info you need to calculate the entire weight for the project.
Choosing the right paint for your job is the first step, then you can calculate the weight.
Before we dig into the paint itself, let’s establish what the various standards for measuring weight and volume are.
Paint is usually measured in gallons, with one gallon and five gallons being the most common sizes you’ll see at your local hardware store. But what is a gallon exactly?
A gallon is a unit for measuring volume, which is simply the amount of space something occupies. The weight and density do not have an effect on volume, therefore a gallon is constant regardless of what you are measuring.
In other words, a gallon of paint, a gallon of milk, and a gallon of water are the same amount of liquid.
The term “gallon” can refer to three different measurements: the U.S. gallon, the imperial gallon, and the U.S. dry gallon. One U.S. gallon is equal to 231 cubic inches (or roughly 3.785 liters). This is the standard gallon measurement you will likely see on your paint.
An imperial gallon, which is used in the United Kingdom, Canada, and some of the Caribbean, is 4.546 liters. Finally, there is the U.S. dry gallon, which is 4.404 liters, but it is rarely used (source).
Since a gallon is a measurement of volume, we need to be able to convert that to weight.
The standard measurement of weight in the United States is the pound but, since the gallon is only a measurement of volume and not density, there is no easy formula for converting gallons to pounds unless you know the specific gravity of the paint.
Different liquids will not have the same density or weight. For example, a gallon of milk weighs 8.6 pounds, while a gallon of water weighs 8.3. This can also vary slightly by temperature.
In order to calculate the weight per gallon, first, you would need to know the density or the specific gravity of the paint. In the case of liquids, the specific gravity is a ratio of the density of the substance compared to the standard density of water.
Sometimes, the specific gravity of paint is listed on a material data safety sheet from the supplier under physical properties. You can multiply this by 8.345 to find pounds per gallon at 39.2°F (4°C) (source).
Types of Paint
There are many different types of paint, and the paint you choose depend on the job at hand. Paint can be broadly divided into two categories: water-based and oil-based.
All paint is made of pigment suspended in a liquid and, as the names would imply, water-based uses water as the primary ingredient, while oil-based uses oil or solvent. In general, oil-based paint is lighter than water-based paint.
Water-based paint is better for the environment, dries quickly, and washes out of brushes and clothing fairly easily. However, it is also not as durable as oil-based paint and may require more coats for a uniform finish.
Water-based paint is the most common type of paint sold in the U.S. and is used for a wide variety of jobs.
Oil-based paint primarily has linseed oil or synthetic alkyd as its base. It releases far more volatile organic compounds (VOCs), which can be harmful to the environment.
If you’ve ever used oil-based paint, you’ve no doubt noticed it has a much harsher odor than water-based. Due to its environmental impact, oil-based paint usage is tightly regulated in many states.
Latex paint is the most common paint used in construction and home-improvement projects.
Chances are the paint on your walls is latex, and if you decide to repaint, latex will be your go-to paint. Its ease of use, quick drying, and relatively simple cleanup make it a convenient option for many paint jobs.
Latex paint is non-toxic and has minimal impact on the environment. It does not release harmful fumes, so moderate ventilation is all that is required when applying it. Also, since it is water-soluble, no harsh chemicals are required to clean brushes or tools.
Before latex paint dries, it will also wash out of clothes or carpet much easier than oil-based paints.
Latex paint does have its drawbacks, however. Since it is mostly water, it can’t be applied in very cold temperatures. Latex paint should be stored above 40 degrees, and colder temperatures can drastically affect drying time.
The high water content of latex paint can also contribute to rusting when used on metal surfaces.
A gallon of latex paint weighs approximately 11.3 pounds (the exact weight may vary by brand). Since one gallon will cover roughly 400 square feet in a single coat, you can see the weight will add up quite a bit if you have a large job, such as the entire interior of a house.
When you figure in multiple coats, ceilings, and areas like doors and trim, you could easily end up needing hundreds of pounds of paint to complete the job.
Once applied, the water evaporates, leaving the pigment behind as a dry coat of color. One gallon of latex paint, once it’s dry, weighs approximately 4 pounds.
Add in a primer coat (which will weigh roughly the same as the paint, depending on the type of primer used) and a second coat of paint, and 400 square feet of walls will end up supporting close to 35 pounds of paint.
While you probably wouldn’t want to have 35 pounds hanging from one small section of wall since it’s spread out in a thin layer over the entire room, this weight has little effect on your walls or ceiling.
Technically speaking, latex paint and acrylic paint are both made from acrylic resin and are water-based. However, acrylic paints utilize an acrylic polymer emulsion and have a higher amount of acrylic in them (source).
Acrylic paint is primarily used in art and craft projects and is also the primary type of paint used as nail polish. Acetone, a polar aprotic solvent, is commonly used to remove nail polish, and can also remove dried acrylic paint from other surfaces.
There are many varieties of acrylic paint, and the weight will vary slightly between them. However, since it is water-based, in general, the weight will be similar to that of latex paint.
A liter of acrylic paint will weigh around 3 pounds, but since it is often sold in even smaller amounts, you’ll more often see ounces as the unit of measurement. However, depending on the brand and color, you can expect a gallon of acrylic paint to weigh between 11 and 12 pounds.
Though the weight may be similar to latex, acrylic paint is thicker, and therefore won’t cover as many square feet as the same amount of latex paint.
A gallon of acrylic paint will cover around 250 square feet. However, since acrylic paint is mostly used for smaller projects, it’s not likely that you would need to cover as large an area like you might with other types of paint (source).
Oil-based paint has a much longer history than water-based, going all the way back to cave paintings. For hundreds of years, oil-based paint was the only option.
These days, it primarily consists of pigment suspended in natural linseed oil or a synthetic solvent called alkyd. Sometimes other oils, such as walnut or safflower oil may be used. Paint thinner or mineral spirits are sometimes added as well to improve the consistency and flow of the paint.
Oil-based paint has a higher toxicity than water-based, so precaution must be used when applying it. Proper ventilation is a must, and a breathing mask may be necessary for large jobs.
It also has a greater effect on the environment, as the volatile organic compounds released contribute to ozone buildup. In addition, the harsh chemicals needed to clean brushes and tools, such as paint thinner or mineral spirits, have their own environmental issues (source).
While cleanup is more difficult and dry time is longer, there are advantages to oil-based paints in certain applications. It is more durable than water-based paint and is, therefore, easier to clean.
It also provides a more uniform finish, so oftentimes only one coat is needed. While you probably wouldn’t use it to paint your walls, it is often used for trim, fixtures, handrails and the like. It is also used for home exteriors, as its durability allows it to stand up to the elements. (source).
The weight of oil-based paint can vary depending on the specific base used, as well as the color, as some colors require more pigment than others. However, since oil has a lower density than water, the resulting paint will be lighter than the same amount of latex or acrylic paint.
In general, a gallon of oil-based paint weighs approximately 6.7 pounds and, like latex paint, it will cover approximately 400 square feet.
When you figure in that multiple coats may not be necessary, the final weight of the dry paint can be significantly lower. This can be an important point for craft or hobby projects.
Enamel paint can refer to a variety of different paints, as the name refers more to the finish than what the paint is made of. It dries quickly to a hard, usually glossy finish that is perfect for cars, boats, and RVs.
The specific weight of enamel paint is hard to pin down due to the broad category of paints that can be called enamel.
In addition to automotive uses, enamel paint is also used for outdoor furniture, as well as decks and stair railings that need to withstand weather and temperature fluctuations. You may also find it in garages and basements, where it is used to seal and protect concrete floors.
If you are painting something where the final dry weight of the paint may be important, whether something small like a pinewood derby car or a large project like a boat, determine if the enamel paint is acrylic or oil-based. Next, refer to the previous sections to determine the weight, keeping in mind that oil-based will be lighter than acrylic.
If you are unsure of which type it is, you may need to contact the paint manufacturer to find out the density of the paint, then multiply the density by the volume (source).
Automotive enamel will generally weigh around 11 pounds per gallon, depending on the brand and color, though, the dry weight will be significantly less.
To give one example where the weight of the automotive paint could have an impact, consider the 747 airliner, where, once dry, the paint can weigh over 500 pounds!
There are many reasons why you might need to calculate the weight of paint. If your painting project is a big one, you’ll need to be able to transport and store the paint prior to using it, for example.
When paint dries, a great deal of the weight simply evaporates, but the dry coat will still have a significant weight that can impact whatever you’re painting.
While the weight of paint on walls and ceilings may not have much of an effect on your home, if you’re painting furniture, completing a craft project, or painting a car, boat, or plane, the added weight can have a major impact.
By being aware of the weight of the paint before you start, you can determine what effect that weight will have on the finished project.