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.
USDA says eggs keep 3 to 5 weeks in the fridge from the day you put them there, often past the carton's sell-by date. FDA suggests using them within 3 weeks for best quality.
The three things 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 date for the store, set by the packer | Not federally; some states require one |
The pack date and plant number usually sit together on the short side of the carton, often with the plant number first. Recall notices often list both, which is a good reason to keep eggs in their carton.
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.
Pack date is about quality more than safety. FSIS's 3-to-5-week guidance is counted from when you refrigerate the eggs at home, not from the pack date. Before that, federal rules require packed shell eggs to be stored and shipped under refrigeration, at an ambient temperature no higher than 45°F.
Sell-by and EXP dates on eggs
A sell-by or EXP date is optional under federal rules, but some states require one. On USDA-graded cartons, USDA limits how far that date can be from the pack date, so it tells you roughly when the eggs were packed too. FSIS notes that the sell-by date will usually expire during the 3-to-5-week storage window and the eggs “will be perfectly safe to use,” provided they've been refrigerated. More on what the phrase means in sell-by dates.
How long eggs keep
Storage Facts
Eggs, refrigerated at 40°F (4°C) or below
- Raw, in shell
- 3–5 weeks
- Best quality (FDA)
- within 3 weeks
- Hard-cooked
- 1 week
- Raw yolks or whites
- 2–4 days
- Out of the fridge
- 2 hours max
- Freezer, in shell
- Don't freeze
The two agencies frame it differently. FSIS and FDA's storage chart both give 3–5 weeks for raw eggs in the shell; FDA's egg safety page says to use them within 3 weeks for best quality. Both assume the eggs stay refrigerated. Keep them in their carton on a shelf rather than in the door, which FDA notes runs warmer, and don't leave refrigerated eggs out for more than 2 hours.
For a food-by-food view, see how long eggs are good after the date.
Eggs are easy to forget because the carton hides them. Scan the sell-by or EXP date when you unpack the groceries, and FreshScan reminds you before the eggs reach it. If your carton only has a pack date, convert it above and add the date by hand.
Free on theApp StoreThe float test measures age, not safety
An egg develops an air cell as it cools after laying, and the cell grows as the egg loses moisture over time. That's why old eggs float. FSIS puts it plainly: a floating egg “is old, but it may be perfectly safe to use.” A sinking egg isn't guaranteed to be good either.
The better check is to crack the egg into a separate bowl and look and smell. A spoiled egg has an unpleasant odor as soon as you open it, raw or cooked. Don't taste it to find out.
Questions 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.
Are eggs still good after the sell-by date?
Often, yes. USDA's FSIS says eggs can be refrigerated 3 to 5 weeks from the day you put them in the fridge, and that the sell-by date will usually pass during that time while the eggs remain safe to use, as long as they've been kept refrigerated at 40°F or below. FDA suggests using them within 3 weeks for best quality. Throw out any egg that smells bad or looks unusual when cracked.
Does the float test tell you if an egg is safe?
No. FSIS explains that an egg floats when its air cell has grown large enough, which means the egg is old, but it may still be perfectly safe. Crack it into a bowl and check for an off odor or unusual appearance instead. A spoiled egg smells unpleasant when you open 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.
Can you freeze eggs in the shell?
No. FDA's storage chart says not to freeze eggs in the shell. Out of the shell, raw yolks and whites can be frozen; the same chart gives them 1 year in the freezer for best quality.
Sources
- Shell Eggs from Farm to Table — USDA Food Safety and Inspection Service. Pack date, sell-by and EXP dates, 3 to 5 weeks, float test
- Cracking the Date Code on Egg Cartons — University of Nebraska–Lincoln Extension
- 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
- What You Need to Know About Egg Safety — U.S. Food and Drug Administration
- Refrigerator & Freezer Storage Chart — U.S. Food and Drug Administration
- Are You Storing Food Safely? — U.S. Food and Drug Administration