How Long Is Formula Good For After Opening
without the guesswork.
Baby Formula Open Shelf Life Calculator — Apply the correct preparation, refrigeration, feeding or exact-label clock while condition and higher-risk infant gates decide first. Includes a practical guide and embedded calculator. Inputs stay in your browser.
The result applies the selected CDC event rule or an exact product-label limit. Preparation, refrigeration and feeding-start times are different clocks.
Context matters.
- Prepared formula must be used within both applicable limits: no more than two hours after preparation and no more than one hour after feeding begins.
- Most powdered formulas say to use an opened container within one month, but the exact label and printed use-by date control; opened liquid products can have different instructions.
- For an infant younger than two months, born prematurely or with a weakened immune system, follow CDC's extra precautions and the child's clinician; do not use this clock to override them.
Sources & scope
This page shows the source trail, jurisdiction and review date alongside the result. Always confirm time-sensitive rules with the linked authority.
What to know before using the result.
Which clock applies to prepared infant formula?
CDC says use prepared formula within two hours of preparation and within one hour after feeding begins. Formula refrigerated immediately and not used for feeding can generally be kept up to 24 hours.
How long is opened powdered formula good for?
Many products say one month after opening, but the exact container label controls. CalcSpan will not assign that period unless the user confirms the current product instruction.
What changes for a premature or medically fragile infant?
Extra precautions may be needed because powdered formula is not sterile. Follow the infant's clinical feeding plan and current public-health guidance rather than relying on a generic timer.