On cartons with the USDA grade shield, the three-digit number (001 to 365, or 366 in a leap year) is the pack date, counted as the day of the year: 001 is January 1 and 263 is September 20 in 2026. The number that starts with P is the packing plant, not a date.
A SELL BY or EXP date is for the store and can be at most 30 days after packing; a best-before or use-by date can be at most 45 days after it. For how long eggs stay good past those dates, see how long eggs are good after the sell-by or expiration date.
What's printed on the carton end
| What you see | What it is | Required? |
|---|---|---|
263 | Pack date: the day of the year the eggs were washed, graded and packed | Yes, on USDA-graded cartons |
P-1234 | Plant number: which USDA plant packed the eggs | Yes, on USDA-graded cartons |
SELL BY or EXP date | A stock-rotation date for the store, set by the packer: at most 30 days after packing | Not federally; some states require one, and some don't allow sell-by |
USE BY or BEST BEFORE date | A quality date: how long the eggs should keep their best quality, at most 45 days after packing | Optional |
| USDA grade shield | The eggs were graded for quality and weight under a USDA grader | No; grading is voluntary |
The pack date and plant number usually sit together on the short side of the carton, often with the plant number first. Keeping eggs in their carton keeps both numbers with them.
Day numbers for the 1st of each month
To convert a pack date without the tool, find the month whose first-day number is closest below yours, then count forward. From March on, leap years run one number higher, because February 29 takes a slot. USDA's Agricultural Marketing Service publishes the same day-of-year chart for egg packers.
| Date | Common year (2026) | Leap year (2028) |
|---|---|---|
| January 1 | 001 | 001 |
| February 1 | 032 | 032 |
| March 1 | 060 | 061 |
| April 1 | 091 | 092 |
| May 1 | 121 | 122 |
| June 1 | 152 | 153 |
| July 1 | 182 | 183 |
| August 1 | 213 | 214 |
| September 1 | 244 | 245 |
| October 1 | 274 | 275 |
| November 1 | 305 | 306 |
| December 1 | 335 | 336 |
Example: 263 in 2026. September 1 is 244, and 263 − 244 = 19, so the pack date is 19 days after September 1: September 20. For every date of the year, use the Julian date calendar.
How old are your eggs?
Subtract the pack date from today. Eggs packed on day 263 and bought on September 26, 2026 (day 269) were 6 days old at the store. The one trap is the new year: a carton bought in early January with a pack date like 360 was packed in late December of the previous year.
The pack date tells you age, not a deadline. USDA's storage advice counts from the day you buy the eggs, not from the pack date.
Sell-by, EXP and best-before dates on eggs
Packers print these “code dates” to help stores rotate stock. On USDA-graded eggs they're optional, but if one is used, USDA's rules apply:
- Expiration dates such as
EXP,SELL BYor “Not to be sold after” must be printed as month and day after the prefix, and can be no more than 30 days after packing. - Quality dates such as
USE BY,USE BEFOREorBEST BEFOREcan be no more than 45 days after packing, counting the pack day.
That also works backward: an EXP date on a graded carton tells you the eggs were packed within the 30 days before it. A sell-by or EXP date isn't a federal requirement, but some states require one, and FSIS notes that some state egg laws don't allow a sell-by date. More on what the phrase means in sell-by dates.
How long eggs keep after these dates
USDA gives raw eggs in the shell 3 to 5 weeks in the refrigerator from the day you buy them, so a sell-by or EXP date usually passes while the eggs are still good to use. A best-before date leaves less room. The full answer, with a week-by-week table and how to check an egg, is in how long eggs are good after the sell-by or expiration date.
Eggs are easy to forget because the carton hides them. Scan the sell-by date when you unpack the groceries, and FreshScan reminds you before the eggs reach it. An EXP date scans when the month is spelled out (EXP OCT 18); a short one like EXP 10/18 may not be read, so type that one in. The app doesn't read the three-digit pack code; if that's the only date on the carton, convert it above and add a date by hand.
Free on theApp StoreQuestions people ask
What does the 3-digit number on an egg carton mean?
It's the pack date: the day of the year the eggs were washed, graded and packed, counted from 001 for January 1 to 365 for December 31 (366 in a leap year). Cartons with the USDA grade shield must show it.
What does the P number on an egg carton mean?
It's the plant number, the official number of the USDA plant that packed the eggs, printed after the letter P. It's used for tracing and recalls. It is not a date.
What does EXP mean on an egg carton?
EXP is an expiration date for the store, the same kind of date as a sell-by date. On cartons with the USDA grade shield it can be no more than 30 days after the eggs were packed. It isn't a safety cutoff: USDA gives eggs 3 to 5 weeks in the fridge from the day you buy them.
Do all egg cartons have a pack date?
Cartons with the USDA grade shield must show the three-digit pack date. Eggs packed without USDA grading follow the egg laws of the state where they're packed or sold, and most states require a pack date.
What does the USDA shield on an egg carton mean?
It means the eggs were graded for quality and checked for weight under the supervision of a licensed USDA grader. Grading is voluntary and paid for by the packer. Grade AA and A eggs have firmer whites and higher yolks than Grade B, which is seldom sold in stores.
Sources
- Shell Eggs from Farm to Table — USDA Food Safety and Inspection Service. Code dates, grades and the grade shield. The FSIS site blocks automated reading; we checked the current text in the Internet Archive copy of August 29, 2026
- Food Product Dating — USDA Food Safety and Inspection Service. Egg carton section: pack date as a day of the year, sell-by rules by state; checked in the Internet Archive copy of September 30, 2026
- Eligibility Requirements for USDA Graded Shell Eggs (final rule, 71 FR 20288) — USDA Agricultural Marketing Service, Federal Register, April 19, 2006. The 30-day sell-by and 45-day use-by limits, each counted including the day of pack
- Shell Egg Day of the Year Chart — USDA Agricultural Marketing Service
- 7 CFR 56.36: Grade marks and labeling of shell eggs — Cornell Law School Legal Information Institute (eCFR). Plant number preceded by the letter P
- Cracking the Date Code on Egg Cartons — University of Nebraska–Lincoln Extension. Eggs from plants without USDA grading follow state law; most states require a pack date