Expiration Date Code Converter

What a Julian date code is

Julian date codes are the 4-digit stamps found on canned goods, cosmetics, and pharmaceuticals. The format used by this tool is YDDD: one digit for the last digit of the year, followed by a 3-digit day-of-year (001–365, or 366 in leap years).

Worked example: 3065

Enter 3065 and the tool splits it into year digit 3 and day-of-year 065. It assumes a 2020s decade, so year digit 3 becomes 2023. Day 65 of 2023 falls after January (31 days) and February (28 days) — 31 + 28 = 59, so day 65 is the 6th day of March. Result: 3/6/2023.

Run the reverse conversion on 03/06/2023 and you get back 3065 — the two directions are inverses of each other.

A real limitation to know about

Because the code only carries one year digit, the tool has to guess the decade. This converter assumes the 2020s (so "3" always means 2023, never 2013 or 2033). If you're reading a code manufactured outside 2020–2029, work out the correct year yourself before trusting the month/day result — the day-of-year math is exact, but the decade guess isn't.

Format reference