How To Tell When Eggs Are Off? Complete Guide

An egg that has gone bad usually announces itself the moment you crack it — a rotten, sulfur-like smell that is impossible to miss. If you are unsure before cracking, the float test gives you a quick clue: a fresh egg sinks in a bowl of water, while an older egg floats because its internal air pocket has grown. But floating does not automatically mean spoiled, and a bad egg can occasionally still sink. The most reliable check is your nose and your eyes once the shell is open.

How To Tell When Eggs Are Off

A spoiled egg is almost always obvious once you get past the shell. The signs are strong and consistent, which is why food safety agencies treat eggs as a relatively easy food to judge.

The clearest signals that an egg has gone bad:

• Smell: A rotten, sulfurous, or otherwise unpleasant odor. This is the single most reliable sign. If it smells wrong, throw it out.
• Appearance of the white: A spoiled egg white may be discolored — pink, green, or iridescent — or unusually thin and watery. Fresh whites are thick and hold their shape around the yolk.
• Appearance of the yolk: A yolk that is flat, breaks easily, or has a strange color is a sign of age or spoilage.
• Texture: A slimy or unusually runny consistency is a red flag.

If any of these appear, discard the egg. Do not taste it to confirm. The smell alone is enough.

One clarification worth knowing: a cloudy egg white is not a sign of spoilage. It usually means the egg is very fresh. Cloudiness comes from carbon dioxide still dissolved in the white, which gradually escapes as the egg ages. An old egg white tends to look clearer, not cloudier.

What Does the Float Test Actually Tell You?

The float test measures air, not bacteria. It tells you how old an egg is, not whether it is safe to eat.

Every egg has a small air cell at its wide end. As the egg ages, moisture evaporates through the porous shell and the air cell grows larger. A fresh egg has a tiny air cell, so it lies flat on the bottom of a bowl of water. An older egg has a bigger air cell and may stand upright or float.

The float test gives you three general results:

• Sinks and lies flat: Very fresh.
• Stands upright or bobs slightly: Older but usually still fine to eat if it smells and looks normal when cracked.
• Floats to the top: Old enough that the air cell is large. This egg is more likely to be spoiled, but floating by itself does not prove it is unsafe.

Here is the part many people get wrong. A floating egg is not automatically a bad egg. It is an old egg. Age raises the odds of spoilage, but the float test cannot detect bacteria. The only way to know for sure is to crack it and check the smell and appearance. If a floating egg smells normal and looks normal, it is generally still safe — though its quality will be lower and it is best used in fully cooked dishes rather than eaten raw or lightly cooked.

How Long Do Eggs Stay Good?

Refrigerated eggs typically keep for three to five weeks from the date you bring them home, according to US food safety guidance. That window assumes you refrigerate them promptly and keep them consistently cold.

Several things shorten that window:

• Temperature swings: Leaving eggs on the counter or moving them in and out of the fridge speeds up spoilage.
• Cracks: A cracked shell lets bacteria in. Use cracked eggs immediately and cook them thoroughly, or discard them.
• Improper storage: Eggs keep best in their original carton on a shelf inside the fridge, not in the door where temperatures fluctuate.

An important detail for US readers: commercially sold eggs in the United States are usually washed, which removes a protective coating on the shell. That is why US guidance says to refrigerate eggs. In some other countries, eggs are not washed and can be stored at room temperature. If you are following US storage advice, keep eggs cold.

Hard-boiled eggs are a different story. Once cooked, they should be refrigerated and used within about one week.

Does the “Best By” Date Mean the Egg Is Bad?

A date on the carton is about quality, not safety. It is not a spoilage deadline.

In the US, egg cartons often carry a “sell by” or “best by” date. These dates are set by the producer or retailer and generally reflect peak freshness. An egg can still be perfectly safe to eat after that date if it has been stored properly and passes the smell and appearance checks.

This is where the float test and the date work together. The date tells you how old the egg is supposed to be. The float test estimates how much moisture it has lost. Your nose and eyes give the final answer on safety.

Do not rely on the date alone in either direction. An egg stored poorly can spoil before its date. An egg stored well can still be good weeks after it.

Are There Risks From Eating a Bad Egg?

Eating a spoiled egg can make you sick, and the main concern with eggs generally is Salmonella bacteria. This is a real risk, not a rare one.

Salmonella can be present on the shell or inside an egg. It is the reason food safety agencies recommend cooking eggs thoroughly and avoiding raw or lightly cooked eggs for people at higher risk. Symptoms of foodborne illness from Salmonella typically include nausea, vomiting, diarrhea, abdominal cramps, and fever, and they usually appear within hours to a few days after eating contaminated food.

Some people face a higher risk of serious illness:

• Adults over 65
• Pregnant women
• Infants and young children
• People with weakened immune systems

For these groups, the guidance is stricter. Cook eggs until both the white and yolk are firm, and avoid foods made with raw or undercooked eggs, such as certain homemade dressings, raw cookie dough, and some soft custards. Pasteurized eggs are an option when a recipe calls for raw or lightly cooked eggs.

A spoiled egg and a Salmonella-contaminated egg are not exactly the same thing. Spoilage is usually caused by other bacteria that produce the telltale rotten smell. Salmonella does not always change the smell, look, or taste of an egg. That is why cooking eggs properly matters even when an egg seems perfectly fine.

What Should You Do With an Egg You Are Unsure About?

When in doubt, throw it out. This is not a throwaway phrase — it is the standard food safety advice, and it applies directly here.

The cost of one egg is trivial compared to the cost of a foodborne illness. If an egg smells off, looks off, or you simply cannot tell, discarding it is the right call.

If you want to reduce guesswork going forward:

• Store eggs in their carton inside the fridge, not in the door.
• Keep track of the date you bought them.
• Use older eggs first, and use them in fully cooked dishes.
• Check eggs one at a time in a separate bowl before adding them to a recipe, so a bad one does not ruin the whole dish.

That last tip is genuinely useful. Cracking eggs into a separate small bowl first means a spoiled egg never contaminates the rest of your ingredients.

Can You Freeze Eggs to Avoid Waste?

Yes, eggs can be frozen, and it is a practical way to use them before they go bad. The key step is to beat them first.

Raw eggs in the shell should not be frozen whole — the liquid expands and the shell can crack. Instead, crack the eggs, beat the yolks and whites together, and freeze them in a sealed container. You can also freeze whites and yolks separately. Yolks alone become thick and gummy unless you add a small amount of salt or sugar, depending on whether you plan to use them in savory or sweet dishes.

Frozen eggs are best used in cooked dishes, such as scrambled eggs, baked goods, and casseroles. They do not perform well for dishes where the egg’s texture matters, like fried eggs.

Freezing is a good option, but it does not rescue an egg that has already spoiled. Freeze eggs while they are still fresh, not as a last resort for ones you suspect are going off.