Julian date converter and today's Julian date
The top line shows today's Julian date, the day of the year, in the formats packs print. Type the number stamped on a can, box or carton and the converter turns it into a calendar date, or pick a date to get its codes. It reads the common food formats: 3 digits for the day of the year, 4 digits for one year digit plus the day, 5 digits for a two-digit year, and 7 digits for a full year. Leap years are handled, so day 366 only exists where it belongs.
What a coded date is
USDA's Food Safety and Inspection Service divides dates on a pack into two kinds. Open dating is a calendar date, printed for shoppers, like "Best if Used By 03/15/26". Closed or coded dating is "a code that consists of a series of letters and/or numbers applied by manufacturers to identify the date and time of production", and it usually turns up on shelf-stable goods: cans, jars, boxes (Food Product Dating).
A day-of-year code is the most common closed format. The year is counted in days from 1 to 365, or 366 in a leap year, so 074 is the 74th day: 15 March in an ordinary year, 14 March in a leap year. That one-day shift is the reason a converter beats counting on a calendar.
The four formats this reads
| Digits | Shape | Example | Reads as |
|---|---|---|---|
| 3 | DDD | 074 | day 74 of the year you pick |
| 4 | YDDD | 6074 | day 74 of the year ending in 6 nearest to today |
| 5 | YYDDD | 26074 | day 74 of the year ending in 26 nearest to today: 2026 |
| 7 | YYYYDDD | 2026074 | day 74 of 2026 |
A short year is the awkward part. One digit cannot say which decade, and two digits cannot say which century. So the converter takes the nearest year ending in those digits, ahead of today or behind it, and says on the result which year it chose. Read in 2026, 6074 is 2026, 7074 is 2027 rather than 2017, and 27001 is 1 January 2027 rather than 1927. Codes ahead of today are real: some manufacturers encode a best-by date this way.
An exact tie, such as a 1 read in 2026 (2021 or 2031), goes to the earlier year, because most coded dates record production. For a one-digit year the result also names the other decade. If you know the pack is from that one, use the 3-digit format and set the year yourself.
Letters in the code are not part of the date. Manufacturers use them for the plant, the line or the shift, and there is no shared standard for them, so this converter asks only for the digits.
Today's Julian date, and a date to its code
The line above the converter is worked out from your device's date each time the page opens, so it is always today's, not the day the page was published. To go the other way, set Convert to a date and pick any day. 26 September 2026, for example, is day 269, written 6269, 26269 or 2026269.
This is the day-of-year "Julian date" of food packs and factories. Astronomers use the same name for a running count of days since 4713 BC, which is a different number, and this page does not compute it.
What the code does not tell you
The date you get out is the date the code encodes, and on most food that is a production or packing date. It is not a "best if used by" date, and the two can be months apart.
Two facts from FSIS are worth holding on to. Dating is not required by federal law in the US, except on infant formula. And the dates that are printed are about quality rather than safety: the agency writes that, other than infant formula, "dates are not an indicator of the product's safety". What a given manufacturer's code means, and how long their product is meant to be at its best, is something only that manufacturer can tell you. Many print a phone number or a code guide on their site.
If the pack has a phrase next to a date rather than a bare number, our guide to best before vs use by vs sell by explains what each phrase means and who it is written for.
Questions
What is today's Julian date?
Today's day of the year, from 1 to 365, or 366 in a leap year, usually written with the year in front. The line at the top of the converter shows it in the YDDD, YYDDD and YYYYDDD formats, from your own device's date. As a check: 26 September 2026 is day 269, so 26269.
How do I turn a date into a Julian code?
Set Convert to a date, then pick the date or press Use today's date. The result lists the code in all four formats. Count the days from 1 January, including the day itself, if you want to check it by hand.
How do I read the Julian date on a can?
Find the stamped or inkjet code, usually on the lid or the bottom, and pull out the run of digits. If it's five digits, the first two are the year and the last three the day of the year. Type the digits above and pick the format if the length is ambiguous.
Is a Julian code the same as an expiry date?
No. On most packaging it records when the product was made or packed. Some manufacturers do encode a best-by date in the same style, which is exactly why the code alone cannot tell you which one you're looking at. The manufacturer can. For how long cans keep, by USDA's chart, see canned food shelf life.
Why does my code have letters in it?
Those identify the plant, the production line or the shift, and sometimes the time of day. They vary by company and have no common meaning, so they are left out of the conversion.
What about day 366?
It exists only in leap years. The converter refuses 366 for an ordinary year, which is a useful check that you picked the right year for a 3-digit code. For a 4- or 5-digit code it reads the nearest year that has a day 366.
Where do I keep track of the dates once I know them?
On paper, an expiration date tracker has a printable sheet. In an app, Duneed flags an item as the date you set approaches.