We often get the question of why an MRE doesn't have an expiration date printed on it. You may have noticed that your MRE's have a funny number at the bottom. What is that thing? Where did these dates come from? Julian Dates, abbreviated JD, are simply a continuous count of days and fractions since noon Universal Time on January 1, 4713 BCE (on the Julian calendar). Ha, clear as mud right? Basically, Jan. 1, 4713 BCE was day 1. Jan. 2, 4713 was day 2 and so forth. However, almost 2.5 million days have transpired since this date. Julian dates are widely used as time variables within astronomical software. The changeover from the Julian calendar to the Gregorian calendar occurred in October of 1582, according to the scheme instituted by Pope Gregory XIII. The changeover to the Gregorian calendar system occurred  only in Roman Catholic countries. Adoption of the Gregorian calendar in the rest of the world progressed slowly. For example, for England and its colonies, the change did not occur until September 1752. Why use these dates? MRE's use Julian Dates because they originated with the military. The time scale that is the basis for these dates is Universal Time. This type of date is useful for the Military because the procurement systems in the military uses the Julian date in the computer programs as a simple standard that doesn't require letters and allows date calculations to be made with out additional supporting programs. Many times, manufactures use this type of date because that is the norm in the industry. However, with consumer knowledge on the rise, many manufacturers are moving towards a more readable manufacture date. How do I read my date? You can check out The Ready Store's MRE Shelf-Life Calculator on the left side bar of our product pages. The first number of the Julian Date represents the year. The last three numbers represent the day that it was manufactured. So for example, if the manufacture date was listed as 1067 that would mean that the MRE was manufactured on March 7, 2011. You can read our previous blog post on how to figure out the manufacture date of your MRE. After locating your manufacture date, use this conversion chart to figure out the date of your MRE.     Check out our full selection of military MRE meals and stock up. We also have a sheet that you can print out and keep with your MREs in case of an emergency. Click here to see the PDF.  Questions? What other questions do you have about Julian Dates? Ask us below.