Understanding Julian Dates

If you’re new to the food storage world, you may be a bit confused about expiration dates and Julian dates, the string of numbers you see on some MREs and  #10 cans. These numbers represent the manufacturer’s Julian dates.  While initially this system can seem confusing, there’s an easy way to decipher these numbers.

The Julian Calendar – Julian dates are based on the Julian calendar which started over 4000 BC. It started by simply qualifying each day as Day 1, Day 2, etc. So, January 1, 4713 BC was Day 1.  January 30 4713 BC was Day 30.

That doesn’t do much for us since we work with the Gregorian calendar now, using days, months, and years. However, many manufacturers, especially MRE and food storage manufacturers depend on Julian dates simply because it’s easier for their computer systems to calculate them.

It’s Like Military Time – Think of it this way, the military uses continuous military time as a 24-hour system so it doesn’t have to differentiate between AM and PM. It takes a bit to get used to military time, but once you do, it’s a very clear way to document time. A Julian date is also a very easy, clear way to document dates. Manufacturers don’t need to use a mix of letters and numbers, work with shorter months/longer months, or adjust to leap year days. It’s simply a number.

Breaking it down – A Julian date is usually a 4 or 5 digit number starting with the last 2 digits of the year the item is made. The last three numbers correlate with the day of the year the product is made.  Here are a couple examples:
Product made January 12, 2018.  Julian Date: 18012.
Product made August 24, 2016.  Julian Date: 16237. (2016 was a leap year.)

If you’d like a Julian cheat sheet, here you go.

Just a reminder- MREs have a 1-5 year shelf-life. The Julian date is NOT the expiration date, but rather the manufacture date. Look at the date and add 1-5 years to figure out when you need to restock.



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