To tell if eggs are good or bad, combine a few simple checks: look at them, smell them, and, if needed, do a quick water test.

Quick Scoop (What to do first)

  • If in doubt, throw it out; food poisoning is not worth the risk.
  • Check the date on the carton (sell-by or best-before) and use it as a guideline, not an absolute rule.
  • Always crack questionable eggs into a separate bowl before adding them to a recipe.

1. The Sniff Test (Most Reliable)

Your nose is your best tool here.

  • Crack the egg into a clean bowl or plate.
  • If it smells sulfurous, rotten, or just “off,” toss it immediately.
  • A good egg usually has little to no noticeable smell.
  • Wash the bowl with hot, soapy water if the egg was bad, so bacteria don’t transfer to other foods.

Think of it like opening milk: if the smell makes you step back, that’s your answer.

2. Visual Check (Shell, White, and Yolk)

Use your eyes before you use your pan.

Shell check

  • Throw it away if the shell is:
    • Cracked (especially if it looks old, not just from you opening it).
* Slimy or wet-feeling (can signal bacterial growth on the shell).

* Powdery with a white coating (may indicate mold).

Inside the egg

Once cracked into a white bowl or plate:

  • Toss the egg if you see:
    • Pink, green, or iridescent (shiny rainbow) tones in the whites or yolk.
* Black or brown moldy-looking spots inside the shell.
  • Not necessarily bad:
    • Little red or dark brown “blood spots” in the white or on the yolk; these are usually harmless and can be removed with a spoon.
  • Texture clues:
    • Very thin, watery whites and a weak, flat yolk usually mean the egg is older and lower quality, though not automatically unsafe.

3. The Water Float Test (Freshness & Age)

The water test is great when you found eggs in the back of the fridge and aren’t sure how old they are.

How to do it

  • Fill a bowl or glass with cold water.
  • Gently place the egg in.

What the positions mean

  • Sinks and lies flat on its side: very fresh egg.
  • Sinks but stands upright on the small end: older, but usually still safe to eat; use soon and cook well.
  • Floats to the top: the egg is very old; best to throw it away.

As eggs age, the air pocket inside gets larger, which makes them float more.

4. Listening and “Shake” Tricks (Extra, Not Primary)

Some people use a “shake test” out of curiosity.

  • Hold the egg gently between thumb and finger at both ends and give a light shake.
  • Some say:
    • A sloshy feel suggests the egg is older.
    • A totally firm, gas-filled feel can indicate a very bad, gassy egg.
  • This method is more anecdotal and less reliable than smell and water tests, so treat it as a bonus clue, not your main test.

Never shake very hard—especially with duck eggs—because truly rotten eggs can occasionally burst when under pressure.

5. Dates, Storage, and Safety

Knowing how long eggs last helps you judge borderline cases.

  • Carton dates:
    • “Sell by” is mainly for the store; eggs can often be fine for weeks beyond if kept cold.
  • General fridge guideline (for clean, properly refrigerated eggs):
    • Many sources suggest whole eggs in the shell can stay usable several weeks past purchase if kept at a consistent cold temperature.
  • Storage tips:
    • Keep eggs in the main body of the fridge, not the door, to avoid temperature swings.
* Store them pointy-end down to help protect the air cell and keep quality a bit longer.

Even if an egg looks and smells normal, it can still very rarely carry bacteria like Salmonella, so always cook eggs to a safe temperature, especially for kids, pregnant people, older adults, or anyone with weaker immunity.

6. Mini “Decision Guide” (Step-by-step)

Use this little mental flowchart when you’re standing in your kitchen with a suspicious egg:

  1. Check the shell.
    • Cracked, slimy, or moldy-looking? → Throw it away.
  1. Do the water test if you’re unsure how old it is.
    • Floats? → Throw it away.
 * Sinks but stands upright? → Probably safe but older; crack and check closely.
  1. Crack into a separate bowl.
    • Bad smell, strange colors (pink/green/iridescent), moldy spots? → Throw it away.
  1. If it passes all that, cook thoroughly and enjoy.

7. “Latest news” and forum vibes

Egg freshness tips have gone a bit “trendy” online lately because more people are cooking at home and raising backyard chickens. You’ll see the water test (“bad eggs float”) repeated constantly in forum threads, often with people sharing funny or gross stories about the one time they cracked a truly rotten egg.

“Bad eggs float.”
This short line shows up again and again in homesteading and lifehack forums, often with everyone chiming in that they didn’t know this until someone told them.

Recently published guides from egg brands and food sites keep emphasizing the same core message: combine multiple checks—shell condition, float test, smell, and appearance—and when in doubt, toss it rather than risk getting sick.

HTML Table: Quick methods at a glance

[1] [1] [1] [3][1] [3] [3][1] [5][1] [5][1] [5][1] [5][1] [1] [5][1] [5][1] [6][1] [1]
Method What you do Good egg sign Bad egg sign
Shell check Look for cracks, slime, or powder on the shell.Dry, clean, uncracked shell.Cracked, slimy, or powdery (mold) shell.
Water float test Place egg in a bowl of cold water.Sinks and lies flat or sinks but stands upright (older but usually safe).Floats toward the surface → very old, discard.
Smell test Crack egg into a bowl and sniff.No real smell or very mild egg smell.Strong, sulfurous, or rotten odor.
Visual inside Inspect whites and yolk in a white dish.Normal yellow yolk, clear to slightly cloudy white.Pink, green, or iridescent color; moldy spots.
Age/Date guide Check best-before or sell-by date and storage conditions.Refrigerated, within or not far beyond date, passes other tests.Very far past date plus fails float/smell/visual checks.

TL;DR

  • Look at the shell, do a water test if you’re unsure, then crack the egg into a separate bowl and smell and inspect it.
  • Any bad smell, weird colors, mold, or floating in water → just bin it and grab another egg.

Information gathered from public forums or data available on the internet and portrayed here.