Unopened powdered baby formula typically lasts 12 to 18 months from the date of manufacture, though some brands extend to 24 months. Every container of infant formula sold in the United States is required by the FDA to carry a “use by” date, and that date is the single most reliable guide to how long your formula will last.
What the “Use By” Date Actually Means
The “use by” date on infant formula isn’t just a suggestion. The FDA requires manufacturers to put it on every container, and it’s based on testing that confirms two things: the formula still contains at least the amount of every nutrient listed on the label, and the product is otherwise safe and acceptable in quality. This makes infant formula unique among food products in the U.S., where most expiration dates are voluntary. For formula, the date is a regulatory requirement tied to nutritional adequacy.
One important detail: the date counts from when the formula was manufactured, not when it appeared on the store shelf. A container that sat in a warehouse for several months before reaching your local store has already used up part of its shelf life. Always check the date before buying, especially during sales or when purchasing in bulk.
Powder vs. Liquid Formulas
Powdered formula has the longest shelf life of the three main types, generally lasting 12 to 24 months unopened depending on the brand. The low moisture content in powder helps prevent bacterial growth and slows nutrient breakdown.
Liquid concentrate and ready-to-feed formulas have shorter shelf lives. Because they already contain water, they’re more vulnerable to degradation over time. Ready-to-feed options are sterile when sealed, which is why they’re often recommended for newborns, but that sterility comes with a trade-off in how long they can sit on a shelf. Regardless of the type, every sealed container will have a specific “use by” date printed on it, and that date is always your best reference point.
Storage Conditions That Shorten Shelf Life
The date on the container assumes you’ve stored the formula properly. If you haven’t, the formula can degrade well before that printed date. Keep unopened formula in a cool, dry area with temperatures between 65°F and 75°F. The acceptable range extends from above freezing (32°F) up to 85°F, but staying in that ideal middle zone gives you the best results.
Heat is the biggest threat to unopened formula. The FDA notes that certain specialty formulas include explicit warnings against exposure to temperatures above 100°F, because heat breaks down vitamins and other nutrients. Even standard formulas lose nutritional quality when stored in hot environments. A garage in summer, a car trunk, or a shelf near an oven can all push temperatures high enough to matter. If your formula has been exposed to sustained heat, the nutrients inside may no longer match what’s listed on the label, even if the date hasn’t passed.
Humidity is the other concern, particularly for powdered formula. Moisture can promote clumping and create conditions where bacteria thrive. A pantry or kitchen cabinet away from the stove and dishwasher is a better choice than under the sink or in a laundry room.
When to Throw Away Unopened Formula
Past the “use by” date is the clearest reason to discard formula, but it’s not the only one. Do not use any formula in a container that is dented, bulging, leaking, or rusty. These are signs that the seal may be compromised, allowing bacteria or air inside. A bulging can is particularly concerning because it can indicate bacterial contamination producing gas.
If the container looks fine but something seems off when you open it, check for changes in color, consistency, or smell. Liquid formulas may show clumps or separation. Powdered formula that has an unusual odor or appears discolored should be discarded. These signs suggest the product has degraded, even if the printed date hasn’t arrived yet.
Can You Use Formula After the Expiration Date?
It’s not recommended. Unlike many pantry staples where “best by” dates reflect peak quality rather than safety, the date on infant formula is directly tied to whether it still delivers the nutrition your baby needs. After that date, key vitamins and minerals may have degraded below the levels listed on the label. Your baby depends on formula as a sole or primary source of nutrition, so even a modest drop in nutrient content matters more than it would for an older child or adult eating a varied diet.
There’s also a safety dimension. Powdered infant formula is not sterile. Over time, even in a sealed container, the risk of bacterial issues increases as preservative effectiveness fades and fats begin to oxidize. The margin of safety built into the “use by” date accounts for this, but once you’re past it, that margin is gone.
Buying and Storing Formula in Bulk
If you’re stocking up, rotate your supply so you use the oldest containers first. Check every “use by” date at the time of purchase and plan your usage so nothing sits past that window. Buying more than a few months’ worth at a time increases the chance that some containers will expire before you reach them, especially with liquid formulas that have shorter shelf lives.
Store all containers off the floor and away from exterior walls, where temperature swings tend to be more extreme. A climate-controlled interior closet or pantry shelf works well. If you’re storing formula in a location you don’t check regularly, set a reminder to inspect dates and container condition every few weeks.