Crack the code! Learn to tell how old those eggs on the supermarket shelf actually are.Hint: they're likely older than you think.

Q: How old are the eggs being sold in the grocery store?

A: It's just about impossible to tell, but they could be up to 2 months old. Yup, really.

In response to a controversial (in some circles, anyway, namely the egg farmers!) meme that I posted on Facebook a few weeks ago stating that I would rather eat a 45-MINUTE old egg than a 45-DAY old egg, I thought I would delve a bit deeper into the question of just how old the average supermarket egg actually is.

And apparently people were's one of the headlines that appeared in the media.

I'm happy to say that my original meme has now officially 'gone viral', having been viewed over 7 million times, and a follow up post is being shared by,, Woman's Day,, Fran Drescher's CancerSchmancer websiteZooey Deschanel's Hello Giggles website and Inquisitir, among others.

Cracking the Egg Carton Code | How Old are Supermarket Eggs?

So, what's the fuss all about?  Well...

Up to 30 Days IN the Carton

By law, an egg can be sold for up to 30 days after the date it was put in the carton. Yes, that says 'put in the carton', not laid or collected, but packaged.

And I'm told (although I can't find anything official in writing to confirm this) that a farmer has up to 30 days to package an egg after it's laid.

So that means a commercially sold egg can be two months old by the time you buy it. 

Sure the egg will be just fine to eat. Not as fresh, of course.

The yolk won't be quite as firm and the whites will be more runny, but it will still be fine to eat. The air sac will be larger since more air has had the chance to seep through the pores in the shell. And there's been a greater chance of bacteria seeping in as well, I would guess.

But hey, on the bright side, that 'up to 60 day old' egg will peel just great when you hard boil it - although if you steam your fresh eggs they'll peel just fine too.  

But I personally would rather eat a fresh egg any day. If you don't have your own chickens, and aren't near a farmers market, or know a friend or local farmer who provides you eggs, you're at the mercy of the commercial farmers, so how can you increase your chances of choosing store bought eggs that are as fresh as possible? 

Well first of all you can pretty much ignore the "sell by" or "best by" dates printed on the egg carton. They are fairly arbitrary. So, how can you tell how old the eggs are?

Cracking the Egg Carton Code

Well, you have to learn the "code".

On each egg carton, there's a number printed, from 1 to 365 (I bet you can see where I'm going with this, can't you?). 

That represents the day of the year the carton was filled: 1 being January 1st and 365 being December 31st. Using the code, you can at least tell when the eggs were put in the carton.

As an example, a friend of mine recently went shopping and found a carton with the code 345 on it. That means the eggs were put in the carton on December 11th. She picked up the carton at the grocery store on January 8th.

That means those eggs were at least 28 days old. (As an aside, the carton had a "sell by" date of January 9th. Which is right in line with the 30 day limit that the eggs can be in the carton.)

I found this carton on the shelf on January 19th. The code of 355 told me that the eggs were packaged ten days before the end of last year, so by January 19th, they were a minimum of 29 days old. Sure, the 'best by' date is still a few weeks away, but these are still pretty old eggs.

Pretty interesting right?

Most cartons will also include a "Best By" date and a "Sell By" date. The "Best By" or "Use By" date can't be more than 45 days past the packaging date. The "Sell By" or "Expiration" date can't be more than 30 days past the packaging date.

And How Long Before Making it INTO the Carton

Then there's the other part of the equation. Trying to determine the date the egg was actually laid. Figuring out how long it was before that egg was put in the carton. 

Which is pretty much impossible to determine - but realize it could be up to another 30 days before the date on the carton (and honestly, is anyone from the government really camped out at egg farms with a stopwatch to determine the time from when the hen lays that egg until it finally reaches the carton? I think not.)

I've read commercial farm claims that most eggs make it into the stores within 1-2 days and almost all make it within 72 hours of being laid. That means the eggs is laid, collected, cleaned, sorted, candled, cartoned, packaged, trucked, unloaded and shelved. Whew! All in 72 hours? Hmmm....

How to Tell How Fresh an Egg Is

An interesting test to try to figure out the age of eggs, either store bought or from your backyard is to do the Float Test.  A very fresh egg will lie on the bottom of a glass of water, while an old egg will start to rise up on one end, and eventually float.

I guess what I'm trying to say here is this. If you can, consider raising your own chickens so you not only know exactly how old your eggs are, but what the chickens that are laying them are eating and, most importantly, how those chickens are treated and their quality of life.

If that's not an option, try to find a local farm, farmers market or check Craig's List to find someone near you selling their eggs. Although you might still want to check the freshness of local eggs as well. As I found out here - you can't fake fresh.

If buying commercially is a must, get in the practice of checking carton dates and codes and at least choose those eggs that are the freshest. 

Nothing beats a fresh egg from your own backyard chickens, but at least you have a fighting chance of choosing the next best alternative once you start looking.

©2016 by Fresh Eggs Daily, Inc. and updated in 2024 for Coop to Kitchen. All rights reserved.