An American egg carton can show a three-digit number such as 247, a “Sell By” date and perhaps a “Best if Used By” date. They are not three versions of the same clock. The most useful starting point on a USDA-graded carton is the pack date: a Julian-style code from 001 to 365 showing the day of the year the eggs were washed, graded and packed.
What does a number such as 247 mean?
USDA requires cartons bearing its grade shield to display a three-digit pack date. January 1 is 001, January 31 is 031, February 1 is 032 in a non-leap year, and December 31 is 365.
Code 247 therefore means the eggs were packed on the 247th day of that year. It is not an expiration date and it does not necessarily equal the laying date; eggs may reach the packing plant after laying.
Sell-by and expiration dates have a 30-day ceiling on USDA-graded cartons
When a carton with the USDA grade shield uses an expiration-style date such as “EXP,” “Sell By” or “Not to be sold after”, USDA says it may be no more than 30 days from the pack date.
That date is strongly tied to retail inventory. It should not be read as proof that every egg becomes unsafe at midnight the next day.
Best-by or use-by quality dates can run longer
USDA also describes dates using wording such as “Use by,” “Use before” or “Best before.” On USDA-graded eggs, this kind of quality dating may not exceed 45 days including the pack date.
Those dates estimate how long the eggs can be expected to maintain quality under ideal storage. Egg whites become thinner and yolks flatter with time even when the eggs remain properly refrigerated.
Refrigerator time is another useful reference
USDA’s home-storage chart gives raw shell eggs about 3–5 weeks in the refrigerator. FDA recommends keeping them at 40 °F or below and, for best quality, using them within about 3 weeks.
Those ranges are measured from purchase and assume prompt, continuous refrigeration. A carton date cannot compensate for eggs that sat warm for hours, cracked shells or uncertain storage.
Keep the eggs in their original carton rather than moving them loose to the refrigerator door. The carton protects shells, preserves the dating information, and limits odor pickup; an interior shelf also avoids the repeated temperature swings that occur each time the door opens.
State rules can add another layer
Federal USDA grading rules do not create one nationwide mandatory sell-by date for every carton. USDA notes that state egg laws may require or restrict certain types of dating.
That is why cartons from different states or producers can look different. The pack date is especially useful because USDA-graded cartons use the same 001–365 convention regardless of the consumer-facing date wording.
Does the shell code tell you the date?
U.S. shell eggs do not use the same producer-code system printed on individual shells that shoppers commonly see in the European Union. The most reliable date information is on the carton rather than on the shell itself.
Can the float test override the date?
No. A floating egg has a larger air cell and is generally older, but USDA explicitly says a floating egg may still be safe. A sinking egg, meanwhile, is not proof that pathogens are absent.
Use the pack date, consumer-facing date, shell condition and refrigeration history together. The water test can add a clue about age but not a safety certificate.
If the carton has been open for a while, the most useful household record is often simply the purchase date. Writing it on the carton can remove guesswork later, especially when several cartons overlap. That practical note does not replace the printed pack code, but it makes the 3–5 week refrigerator guidance much easier to apply.
The practical reading order
First find the 001–365 pack date. Then read any sell-by/expiration or best-by wording. Finally, consider how long the carton has actually been refrigerated at home. On USDA-graded eggs, sell-by/expiration cannot exceed 30 days after packing, quality dating cannot exceed 45 days including packing, and the home refrigerator reference is about 3–5 weeks.
Sources
- USDA FSIS — Shell Eggs from Farm to Table — Explains pack dates, 30-day expiration/sell-by limit, 45-day quality dating and refrigerated storage.
- USDA FSIS — Food Product Dating — Explains the 001–365 pack-date system and the relationship between pack date and sell-by dating.
- FDA — What You Need to Know About Egg Safety — Refrigeration at 40 °F or below and use within about 3 weeks for best quality.