Properly refrigerated eggs are generally safe to eat three to five weeks past their “best by” date.
You crack an egg into a hot pan and pause. The carton says “best by” three weeks ago, and suddenly that perfect fried egg feels like a gamble. Most people have stood in this exact spot, wondering whether to trust their eyes or the date stamp.
The truth is more reassuring than you might think. Those dates on egg cartons are mainly about peak freshness, not safety. As long as your eggs have been refrigerated at 40°F or below, they can stay perfectly good well past that printed date. Here is how to tell for sure.
What Those Dates on the Carton Really Mean
“Sell by,” “best by,” and “use by” all sound similar, but only one of them concerns safety. The USDA clarifies in its egg carton date meaning that these are voluntary quality dates aimed at retailers.
A “sell by” date tells the store how long to display the eggs. A “best by” date suggests when flavor and texture peak. Neither is a safety deadline. Eggs packed inside that carton can remain wholesome for weeks beyond that printed number.
The actual clock that matters is how long the eggs have been refrigerated. Proper storage at 40°F or below keeps eggs in good condition for three to five weeks after the carton date. Some commercial producers consider 45 days from packing as their own cut-off, though that is not a USDA standard.
Why the Floating Test Is Your Go-To Kitchen Trick
The float test feels like an old wives’ tale, but it works on simple physics. As an egg ages, moisture and carbon dioxide escape through the porous shell, making the air cell inside the egg grow larger. That expanding air pocket changes how the egg behaves in water.
- The sink-and-lay-flat test: If the egg sinks and lies flat on its side at the bottom of a bowl of water, it is very fresh. The air cell is tiny.
- The upright sink test: If the egg sinks but stands upright on its bottom point, it is still good but older. The air cell has grown enough to tilt the egg. Eat these soon.
- The slight tilt test: If the wide end of the egg lifts slightly off the bottom, the egg is still safe but approaching the end of its prime. Use it for hard boiling or baking.
- The float test: If the egg bobs or floats to the top, the air cell is large enough to make the egg buoyant. This indicates the egg is old and should be discarded.
- The salt water alternative: Dissolve two tablespoons of salt in two cups of water and place the egg in the solution. If it floats, it is too old. This method is slightly more precise for borderline eggs.
One note many home cooks miss: submerging an egg in water washes off the natural “bloom” that seals the shell. After testing, refrigerate the egg immediately and use it within a few days rather than returning it to the carton for weeks.
Testing Eggs Past Their Date at Home
So when people ask about eggs past their best by date, the honest answer is that dating stamps tell an incomplete story. The USDA confirms that “best by” and “sell by” dates are strictly quality markers, and properly stored eggs can be safe and palatable for weeks afterward.
| Date Label | What It Means | Safety Relevance |
|---|---|---|
| Sell By | Last day for store display | None — eggs remain safe if refrigerated |
| Best By | Peak quality and flavor window | None — eggs can be fine for weeks after |
| Use By | Last date recommended for peak quality | Low — still safe if stored properly |
| Pack Date | Julian date of when eggs were packed | Useful for knowing true age (3-digit code) |
| Freeze By | Date for freezing whole eggs | Safety date for frozen storage only |
The pack date is the most honest number on the carton. It is a three-digit code between 001 and 365 that tells you the actual day the eggs were processed. Eggs are typically good for four to five weeks from that date, not the sell-by date on the front.
How to Check an Egg Without Cracking It
Sometimes you want answers before you break the shell. A few sensory checks can tell you a lot without making a mess in your bowl.
- Check the carton date first: Look for the pack date (a three-digit code near the expiration date). Eggs packed within the last month are typically fine.
- Do the float test: Place the whole egg in a bowl of cold water. A fresh egg sinks; a floating egg is too old and should go in the compost.
- Listen for a rattle: Hold the egg near your ear and give it a gentle shake. A fresh egg makes almost no sound. A sloshing or rattling noise means the yolk has thinned and the egg is older.
- Smell the shell: A sulfur or rotten smell from the outside is a clear sign of spoilage. Fresh eggs have little to no odor.
- Crack into a separate bowl: If you are still unsure, crack the egg into a small bowl before adding it to your dish. A fresh egg has a firm yolk and thick white. A watery white or flat yolk means it is older but still usable if it smells fine.
The sniff test after cracking is the most reliable method. A bad egg will have an unmistakable sulfur odor that makes the decision instant.
When You Should Toss That Egg
Even with proper refrigeration, eggs eventually spoil. Healthline explains that the egg float test science is based on the enlarging air cell, but the float test alone does not guarantee safety. A floating egg has likely been around too long.
Spoiled eggs can carry Salmonella enteritidis, which thrives at temperatures above 40°F. If your refrigerator runs warm or the eggs were left out for more than two hours, toss them regardless of the date or float test result.
| Sign of Spoilage | What to Look For |
|---|---|
| Sulfur smell | Rotten egg odor when cracked — discard immediately |
| Pink or iridescent white | Bacterial growth — do not eat |
| Mold on the shell | Fungal growth — discard the whole carton |
One more thing to watch for: eggs that have been sitting in a warm grocery store aisle or your car on a hot day are more vulnerable. If the cold chain is broken even briefly, the safety window shrinks fast.
The Bottom Line
Eggs past their best by date are generally safe as long as they have been continuously refrigerated at 40°F or below. The date on the carton is a freshness suggestion, not a safety warning. Use the float test as a quick check, but trust your nose above all — a bad egg smells unmistakably wrong.
For specific questions about egg safety or proper storage, the USDA Meat and Poultry Hotline can provide guidance tailored to how long your carton has been in the fridge and whether the power ever went out.
References & Sources
- Usda. “What Kind of Dates Are on Cartons of Fresh Eggs” The “best by” or “sell by” date on an egg carton is a quality indicator, not a safety date.
- Healthline. “Tell If Eggs Are Bad” The egg float test works because as an egg ages, moisture and carbon dioxide escape through the porous shell, causing the air cell inside to grow larger.