How Long Does Leftover Paint Last?

    Here are some telltale signs that your paint is past its prime

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    Overhead shot of old paint cans Photo: iStock

    It’s always a good idea to save some leftover paint, whether it’s for touch-ups or a small paint project. But if you don’t store it properly, years later—when hallway walls, exterior doors, or window casings need a little TLC—you might find that it has deteriorated beyond the point of being able to use it.

    Consumer Reports tests water-based latex paints, the most popular type. They’re easy to apply and easy to clean compared with oil-based paints. See how almost two dozen lines of paint perform in our interior paint ratings.

    Leftover latex paint can last years, even a decade, or go bad in mere months. “When the paint can is bulging or the lid is puffed up, you know it’s bad,” says Enrique de Paz, who oversees Consumer Reports’ paint tests. “It means microorganisms are eating the paint and giving off gas, which generates pressure and inflates the can.”

    How We Test Interior Paints

    Using nontinted base paints (before color is added), we evaluate how well each covers dark colors and resists stains. The results show whether the paint provides even and thorough coverage and can stand up to wear and tear.


    For the coverage test, we apply one consistent coat to cardstock that has been painted black. After it dries, we use an instrument called a colorimeter to measure how well the paint covers the black paint. We do this twice per paint sample and average the results.

    For stain resistance, our testers apply paint to a plastic panel. After it dries, they apply two lines of soil—coffee and a sootlike substance—and allow them to dry. They then wash the painted panels and use the colorimeter to measure the color of the paint on the rinsed areas. The closer the cleaned portions are to the original coat, the more stain-resistant the paint.

    What to Look for With Old Cans of Paint

    In addition to a puffed-up lid or bulging can, signs that paint is past its prime include a thick, rubberlike film topping it, or paint that doesn’t mix well when stirred or doesn’t stay uniformly blended for 10 to 15 minutes after mixing.

    Even if your paint seems okay, it’s a good idea to try it out on a piece of cardboard. You want to make sure that it can still be applied easily with a brush or roller, that the color is uniform, and that the surface is smooth and free of visible particles.

    “Once you’re ready to paint, use a brush or roller to blend the paint into what’s already on the surface,” de Paz says. “You want to go beyond the spot you’re touching up.” If the touched-up spot is noticeable when dry, try again. The last resort is to repaint the entire area.

    What to Do With Leftover Paint

    If it’s good, save it. The best way to preserve latex paint is to store it in an airtight container to keep the water in it from evaporating and to prevent microorganisms from getting in. You can keep it in the original can or transfer the paint to a clean jar with a screw-on lid. Keep it at room temperature. That means don’t store it in a garage or shed, where temperature extremes can ruin the paint. Label leftover paint—“Kids’ bedroom walls, April 2022”—so that years from now you’ll know where you used it.

    If it’s bad, dispose of it. It’s important to properly dispose of unsalvageable old paint. To find out what to do where you live, check the website of your municipal or county government, or call your local department of public works. Go to Earth911 for more details on the disposal of leftover paint.

    And if you just tossed your leftover paint and need to buy more, we’ve highlighted a few of our top picks, listed here in alphabetical order. You’ll notice a couple of them have Greenguard Gold certification, meaning they emit lower levels of volatile organic compounds, or VOCs—particularly formaldehyde—than the industry standard. VOCs are chemicals that can easily become airborne and affect your health, according to the Environmental Protection Agency. Low levels of VOCs—some paints even come with a “zero VOCs” claim—are ideal for interior paint projects.

    Headshot of CRO Home Editor Tanya Christian

    Tanya A. Christian

    I've spent more than a decade covering lifestyle, news, and policy. At Consumer Reports, I'm happy to sit at the intersection of these specialties, writing about appliances, product safety and advocacy, consumer fairness, and the best tools and products to help you spruce up your home. When I'm not putting pen to paper, I'm exploring new cultures through travel and taking on home makeover projects, one room at a time.