Julian code formats on food
| Format | Example | Means | Where you'll see it |
|---|---|---|---|
| DDD | 263 | Day 263 (year not printed) | Egg cartons with the USDA grade shield |
| YDDD | 6263 | Year ending in 6, day 263 | Canned and boxed food codes |
| YYDDD | 26263 | 2026, day 263 | Canned food, dairy, production codes |
| YYYYDDD | 2026263 | 2026, day 263 | Industrial and export labels |
| DDDY / DDDYY | 2636 / 26326 | Day 263, year last | Some manufacturers' codes |
Day 263 is September 20 in a common year like 2026, and September 19 in a leap year like 2028. For a month-by-month table, see the Julian date calendar.
Egg cartons
USDA-graded egg cartons must show the pack date as a three-digit day of the year, the day the eggs were washed, graded and packed. The number that starts with P (like P1234) is the plant that packed them, not a date. The egg carton guide has a converter preset for eggs and explains how long they keep.
Cans and packaged food
Codes on cans are chosen by each manufacturer and often mix a Julian date with plant, line and time codes. There's no universal decoder. If you can pick out a run of digits that looks like YDDD or YYDDD, this converter will tell you the date it represents; to be sure, check the manufacturer's website or customer line. More in how to read date codes on canned food.
A pack date is not an expiration date
Julian codes almost always record when food was made or packed. How long it keeps from there depends on the food and how it's stored. If the package also prints a best-by or use-by date, that's the one to follow; see packed-on dates vs expiration dates.
Questions people ask
What is a Julian date on food?
On food packaging, a 'Julian date' is the day of the year written as a number: 001 is January 1 and 365 is December 31 (366 in a leap year). Strictly speaking this is an ordinal date, not the astronomers' Julian Day Number, but the food industry calls it a Julian date. It usually records when the food was packed or made, not when it expires.
How do I know which year a three-digit code means?
It isn't printed, so you infer it. A pack date can't be in the future, so the converter uses the most recent date with that day number: this year if the day has already happened, otherwise last year. Eggs are sold within weeks of packing, so that's almost always right.
Is 4-digit code 6263 year-first or year-last?
Most food codes that include a single year digit put it first (YDDD: 6263 = day 263 of 2026), but some manufacturers put it last (DDDY). The converter reads four digits as YDDD by default and shows what the year-last reading would be, so you can compare both with the product in your hand.
Does 2028 have a day 366?
Yes. Leap years (2024, 2028, 2032) have 366 days, so from March 1 onward every day number is one higher than in a common year. The converter accounts for this; a code of 366 in a non-leap year is rejected as invalid.
Sources
- Shell Eggs from Farm to Table — USDA Food Safety and Inspection Service
- Food Product Dating — USDA Food Safety and Inspection Service