Eggs are the food people throw out on a technicality. The carton says a date, the date has passed, into the bin they go. Meanwhile they were probably fine for another two weeks.
The number that matters
The USDA's guidance is simple: eggs in their shells keep for 3 to 5 weeks in the refrigerator, at 40°F or below. That clock starts from the day you bring them home, not from the date printed on the carton.
Hard-boiled is a different story, and a much shorter one. Hard-boiled eggs get about a week, shell on or off.
Why the carton date isn't the expiry date
Here's the part that explains everything else. That Sell-By or Use-By date is a store stocking instruction, not a safety deadline. On USDA-graded cartons it can't be set more than 30 days after the eggs were packed, which means it usually lands well before the eggs are actually finished.
There's a better number hiding on the carton. Look on the short side for a three-digit code between 001 and 365. That's the Julian date, the day of the year the eggs were packed. 001 is January 1, 365 is December 31. Find that number, count forward, and you know how old your eggs genuinely are instead of guessing from a date the store chose.
Same principle as best-by versus use-by versus sell-by on everything else in the kitchen: most of those dates are about quality, not safety.
What the float test actually measures
You've seen this one. Drop the egg in water. Sinks flat, it's fresh. Stands on end or floats, throw it out.
The mechanism is real. An eggshell is porous, so over time moisture evaporates out and air seeps in, and the air cell inside the egg grows. A bigger air cell means more buoyancy. So a floating egg is genuinely an old egg.
But here's what most versions of this tip skip: age and safety are not the same thing.
- A floating egg is old. That doesn't automatically make it unsafe, and if it's been properly refrigerated the whole time it may still be perfectly fine to cook.
- A sinking egg is young. That doesn't make it guaranteed safe. Contamination that predates the packing date won't affect buoyancy at all.
So use the float test the way it deserves: as a rough age check when you've lost track, not as a verdict. The real test is cracking it into a separate bowl first. A bad egg announces itself immediately with a sulfurous, unmistakable smell. That's the one signal worth trusting, and it's why you crack into a bowl instead of straight into the pan with five good eggs.
Toss it regardless of the calendar if you see:
- A genuinely foul or sulfur smell on cracking
- Pink, iridescent, or greenish tint in the white
- A cracked or leaking shell
- Anything slimy or powdery on the outside of the shell
Where you keep them changes the answer
Three to five weeks assumes the eggs are actually staying cold. Two habits quietly shorten it:
- The egg tray in the door. Nearly every fridge has one, and it's the worst spot in the fridge for eggs. The door swings into a warm kitchen several times a day, so the temperature there fluctuates more than anywhere else. Porous shells plus swinging temperatures is exactly the combination you don't want. Put them on a shelf instead, toward the back where it's coldest and steadiest.
- Taking them out of the carton. The carton is doing real work. It shields the eggs from absorbing strong smells through those same porous shells, it cushions them, and it's where the pack date is printed. Leave them in it.
Two more worth knowing: don't wash store-bought eggs before storing them, since they were already washed and sanitized at the plant and rewashing strips the protective coating. And don't freeze eggs in the shell. They expand and crack. Raw whites freeze fine on their own if you need to save them.
The part underneath
None of this is hard to follow. The hard part is that eggs are invisible.
They sit in a closed carton behind other things, they don't smell or wilt or go visibly sad the way produce does, and there's no moment where they remind you they exist. So you buy a second dozen because you weren't sure, or you toss a good dozen because you couldn't remember when you bought them. Both come from the same missing piece of information: what day did these get here.
Write the date on the carton in marker and that's solved for a dollar. Or let something else keep the clock for you.