Expiration Date Code Converter

Date code formats the converter reads

Choose the format that matches your code. The page does not guess: the same digits can spell different dates in different formats, so the result is only as good as the format you pick.

Spaces in the code are ignored. In the letter format the page skips the letter, because its meaning, such as a plant or a production line, is set by each manufacturer.

YYMMDD is the form the GS1 barcode standard uses for production, best-before and expiration dates. The GS1 pattern for these dates also accepts 00 as the day. The page then shows only the month and the year.

Show every format that fits lists each reading that gives a real date, side by side. It is a way to see how ambiguous a code is, not a way to find out which reading is right.

Julian date codes and leap years

A day-of-year code, often called a Julian date on packaging, counts the days from 1 January. Day 001 is 1 January and day 032 is 1 February. To read 24035 by hand: the year is 2024, and day 35 is 31 days of January plus 4, so 4 February.

From March onwards the count depends on whether the year is a leap year. A leap year has a 29 February and 366 days.

Years that divide by 4 are leap years, except century years, which must divide by 400: 2024 and 2000 are leap years, 2023 and 2100 are not. The page rejects day 366 for a year that has only 365 days.

Two-digit and one-digit years

A two-digit year does not say which century it belongs to. The page reads it as 2000 to 2099 unless you switch Two-digit years mean to 1900 to 1999. Nothing is switched for you, so 31001 is 1 January 2031 until you say otherwise.

A one-digit year is worse: it repeats every ten years. For YDDD codes the page shows three candidates, which are the most recent year ending in that digit, the year ten before it and the year ten after it.

In 2026, 4035 gives 4 February 2014, 2024 and 2034. Only what you know about the product can tell you which is right.

Six digits can spell three dates

A six-digit code has no marker for the order of its parts. Take 020424:

• as MMDDYY it is 4 February 2024;
• as DDMMYY it is 2 April 2024;
• as YYMMDD it is 24 April 2002.

All three are real dates. If the package does not say which order is used, the code cannot be read with certainty.

YYDDD and YYMMDD codes have one useful property: in a list of codes of the same format from one century, a larger number is a later date. To put such a list in date order, sort them with the alphabetical order generator, which compares numbers by value.

What a date code can and cannot tell you

The US Food Safety and Inspection Service (FSIS) separates open dating, a calendar date applied by the manufacturer or retailer, from closed dating, a code of letters and numbers that the manufacturer applies to identify when the product was made.

FSIS says can codes exist to track products and to help manufacturers rotate stock and find products in a recall, that they refer to the date of canning, and that they are not meant for shoppers to read as Best if Used By dates. It also notes that, except for infant formula, US federal rules do not require product dating at all.

So a decoded date is not automatically an expiry date. It may be the day the product was made or packed.

How long a product keeps after that depends on the product and how it has been stored, and this page makes no statement about that. For a question about a specific product, contact the manufacturer.

To write a date for an engraving or a title page instead, the Roman numeral converter turns any date into Roman numerals. Other small converters, for colors, card prefixes and files, are under everyday tools.