How Long Is Formula Good For After Opening
Apply the correct preparation, refrigeration, feeding or exact-label clock while condition and higher-risk infant gates decide first. Sensitive 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
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Apply the correct preparation, refrigeration, feeding or exact-label clock while condition and higher-risk infant gates decide first. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Formula event, Event date, Event time, Formula was prepared on and Formula was prepared at and 6 additional fields supplied in the form.
- Apply the scope. It applies the United States infant formula handling — CDC event-specific limits plus exact product label reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
The result applies the selected CDC event rule or an exact product-label limit. Preparation, refrigeration and feeding-start times are different clocks.
- Use / discard boundaryAug 30, 2026 at 10:00
Calculation purpose: Apply the correct preparation, refrigeration, feeding or exact-label clock while condition and higher-risk infant gates decide first. This is a high-sensitivity reference output; the linked authority or qualified professional controls the final decision.
Calendar inputs use plain year-month-day semantics. Leap days, month ends, date-pair order and unsupported dates are checked before the result is shown.
Rule set 2.0.0 · Last reviewed 2026-08-20 · Next review due 2027-02-20. The source panel below contains the linked evidence.
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.