Key Takeaways
- The float test tells you how old an egg is — not whether it’s safe to eat. A floating egg may still be perfectly edible. A sinking egg can occasionally be bad. The float test is a starting point, not a verdict.
- According to the USDA, eggs can be safely consumed 3–5 weeks after purchase when refrigerated at 40°F or below — often well beyond the sell-by date printed on the carton.
- The smell test is the most reliable safety check. A truly bad egg produces a sulfurous, unmistakable odor the moment you crack it. If it smells fine, it almost certainly is fine.
- The Julian date on your egg carton is the most accurate freshness indicator — it tells you exactly what day of the year the eggs were packed, counting from January 1. Day 001 = January 1. Day 365 = December 31.
- The single habit that prevents ruined recipes: always crack each egg into a separate small bowl before adding to your dish. This costs you 10 extra seconds and has saved countless batches of pancake batter, cookie dough, and scrambled eggs.
You’re standing at the fridge holding a carton of eggs. The sell-by date says last Tuesday. You’ve been quietly avoiding this moment for three days, because you don’t actually know what “sell-by” means, or whether these eggs are fine or a salmonella situation waiting to happen, or whether the thing you read about floating eggs is actually true.
This is the moment almost everyone has experienced — and the advice floating around (no pun intended) is genuinely contradictory. Some sources say float = bad, throw it out, no exceptions. Others say that’s totally wrong and you’re wasting perfectly good food. Reddit threads on this topic tend to devolve into heated debate within about four comments.
Here’s the honest truth: the confusion exists because people are conflating two different questions. Is this egg fresh? is a different question from Is this egg safe to eat? Most tests answer the first question. Most people are actually asking the second one. This guide separates them clearly — and gives you the practical system that ends the guessing for good.
First, Decode the Dates on Your Egg Carton
Before any tests, let’s solve the date label problem, because this is where most of the confusion begins.
There are up to four different date-related things printed on egg cartons in the United States, and they don’t all mean the same thing.
The Julian Date (Pack Date)
This is the one almost nobody explains. On the side of most egg cartons, you’ll find a three-digit number — something like 032, or 187, or 301. This is the Julian date, which represents the day of the year the eggs were packed.
- 001 = January 1
- 032 = February 1
- 100 = April 10
- 200 = July 19
- 300 = October 27
- 365 = December 31
If you see 245 on your egg carton, those eggs were packed on September 2nd (the 245th day of the year). Now you have an actual age, not just a vague “sell by” label.
Why this matters: The USDA recommends using eggs within 45 days of the pack date. So if your Julian date is 245 (September 2) and today is October 1 (day 274), you have 29 days elapsed — still well within the safe window, regardless of what any “sell by” label says.
Sell-By Date
This is a retailer’s inventory date, not a food safety cutoff. The FDA and USDA both explicitly state that eggs can be safely eaten for 3–5 weeks after the sell-by date if properly refrigerated. The sell-by date is when the store is supposed to stop selling them — not when you’re supposed to stop eating them.
Editor’s take: The sell-by date exists for store inventory management. It was never designed to tell you when to throw your eggs away. This distinction alone could save most families from tossing perfectly good eggs every month.
Best-By / Best-Before Date
A quality indicator, not a safety cutoff. After this date, the egg may not perform as well for certain applications (you might notice a more watery white, a flatter yolk), but it’s generally still safe if properly stored.
Expiration Date (EXP)
Only some states require this, and when present, it’s typically no more than 30 days after the pack date for commercially sold eggs. This is the closest thing to a hard safety boundary on the carton — though even here, the USDA notes eggs often remain safe beyond it.
The practical takeaway: Ignore the “sell by” date for food safety decisions. Find the Julian date, calculate how many days have passed since packing, and use 45 days as your working guideline. Everything else is supplementary.
How to Tell If Eggs Are Still Good: The Float Test (And Its Limits)
The float test is real, it works, and it’s been used for generations. It’s also widely misunderstood in a way that causes people to either throw away good eggs or feel false security about questionable ones.
How to Do the Float Test
Fill a bowl or glass with enough cold water to fully submerge an egg. Gently lower the egg in — don’t drop it.
What you’re observing: The position of the egg tells you the size of its internal air cell.
When an egg is laid, it’s almost entirely liquid inside. Over time, moisture evaporates through the porous shell, and the air cell at the wide end of the egg expands. The larger the air cell, the more the egg floats.
| Position in water | What it means | What to do |
|---|---|---|
| Lies flat on bottom | Very fresh (pack date within ~1 week) | Use for anything |
| Sinks but tilts slightly | Still fresh, slightly older | Use for anything |
| Stands upright on bottom | Older but generally still safe | Use for hard-boiling, baking |
| Floats completely | Old, air cell large | Crack and smell before using |
The Part Most Guides Get Wrong
Here’s where the internet consistently misleads people: floating does not equal rotten.
A floating egg has a large air cell — meaning it’s older. But “older” and “bad” are not synonyms. The USDA explicitly acknowledges that a floating egg “may be perfectly safe to use” and recommends cracking it into a bowl to assess it before deciding.
What the float test cannot detect:
- Bacterial contamination inside eggs that haven’t yet produced gas
- Early-stage Salmonella (which has no smell and no visible signs)
- Spoilage in eggs where the shell integrity is compromised in non-obvious ways
What the float test can detect:
- How much moisture the egg has lost (approximate age)
- Eggs so old they’ve produced gas inside (these will smell immediately upon cracking)
So use the float test as a first filter — a starting point. But don’t let a floating egg go directly in the trash without opening it first. You might be throwing away a perfectly good egg.
The Most Reliable Method: The Smell Test After Cracking
Of all the methods for how to tell if eggs are still good, this one has the highest accuracy — and the least ambiguity.
Crack the egg into a small bowl (not directly into your recipe). Then smell it.
A truly bad egg — one with active bacterial decomposition — produces a sulfurous smell that is instant, unmistakable, and deeply unpleasant. There is no subtlety here. You will not wonder “hmm, is that a bad smell?” You will know immediately and viscerally. It’s the kind of smell that sends you backing out of the kitchen.
If it smells fine: It is almost certainly fine to use. Even older eggs that floated in the float test typically smell completely neutral when cracked — because the air cell expansion is just physics, not bacterial activity.
If it smells off in any way: Discard immediately. Don’t cook it, don’t investigate further. The bacteria responsible for the sulfurous smell in eggs (primarily hydrogen sulfide-producing bacteria) can cause serious foodborne illness.
What to Look for When You Crack It
Beyond smell, give the egg a visual check in the bowl:
Fresh egg: Yolk sits high and rounded, white is thick and stays close to the yolk, very little watery white spreading out.
Older but still safe egg: Yolk is flatter, white is thinner and more spread out. This is just age affecting texture — the egg is safe, just not ideal for applications where appearance matters (poaching, frying where you want a neat shape). Fine for scrambling, baking, omelets.
Potentially bad egg (check smell): Very watery white that spreads almost flat, discolored yolk (pink, green, or very dark), visible abnormalities. Combined with any unusual smell: discard.
Definitely bad egg: Any sulfurous or rotten smell, visible mold, pink or iridescent white, black or green spots in the yolk.
The Habit That Prevents Ruined Recipes
One of the highest-upvoted pieces of advice across every egg-related thread on Reddit, cooking forums, and experienced home cook communities is this: always crack each egg into a separate bowl before adding it to anything.
This sounds tedious. It adds maybe 10 seconds per egg. And it has prevented more ruined batches of cake batter, pancake mix, pasta dough, and custard than any other single kitchen habit.
Here’s the scenario it prevents: you’re making a double batch of birthday cake. You crack the seventh egg directly into the bowl with everything else. It’s bad. Now your entire recipe is contaminated. The cake can’t be saved. The ingredients, the time, the planning — all lost.
Compare that to: you crack the seventh egg into a small bowl, it smells immediately wrong, you discard just that one egg, rinse the bowl, and continue with a fresh egg.
This is the practical system. It costs you nothing meaningful and protects everything.
If you have even a slight uncertainty about an egg — it’s been a while, you can’t find the Julian date, the float test was ambiguous — crack it into a separate bowl first. Every time.
Does Refrigeration Actually Matter? The Science of Egg Storage
Eggs sold in the United States are required to be washed before sale — a process that removes the natural protective coating (called the “bloom” or “cuticle”) that unwashed eggs have. This coating seals the pores of the shell, slowing moisture evaporation and bacterial entry.
Once that coating is removed, the eggshell is more porous. American-style washed eggs must be refrigerated — this is not optional and not a cultural preference. Refrigeration slows both moisture loss and bacterial growth significantly.
According to the FDA, refrigerated eggs (at 40°F or below) remain safe for 3–5 weeks after purchase. Unrefrigerated, washed eggs deteriorate within days to a week.
The temperature danger zone: The CDC identifies 40°F–140°F as the bacterial danger zone for most foods. Eggs left at room temperature for more than 2 hours in a warm kitchen should be treated with extra caution — they’ve been in the danger zone long enough for bacterial growth to accelerate.
Where in the Fridge to Keep Eggs
Not the door. This is the warmest, most temperature-variable location in the refrigerator — every time you open the door, the eggs experience temperature fluctuation. The original carton, kept in the main body of the fridge (a middle shelf is ideal), protects them from temperature swings and light exposure, and the carton’s markings give you date information.
Eggs absorb odors through their porous shells. Keep them away from strong-smelling foods — onions, garlic, aged cheeses — or keep them in their original sealed carton, which provides sufficient odor barrier.
Specific Scenarios: What to Actually Do
“My eggs expired three days ago.” Check the Julian date. If it’s been fewer than 45 days since packing, do the float test, then crack into a separate bowl and smell. Eggs routinely remain safe well past sell-by dates.
“My egg floated but it looked and smelled completely normal when I cracked it.” It was safe to eat. You made the right call by checking, and the result told you the answer. A floating egg that smells and looks fine is just an older egg — not a bad one.
“I cracked an egg directly into my batter before I realized it might be bad.” This is the scenario the separate-bowl habit prevents. If you’ve already mixed it in and the smell of the dish is now off: discard the whole batch. Cooking does not neutralize the toxins produced by some egg-spoiling bacteria. If the overall dish smells fine after mixing: use your judgment, but the risk is real.
“My power went out and the eggs were at room temperature for several hours.” If the temperature stayed below 40°F (unlikely without power during warm weather) or the outage was under 2 hours: eggs are likely fine. Beyond 2 hours in temperatures above 40°F: FoodSafety.gov recommends discarding. The risk isn’t worth it, and eggs are inexpensive enough that it’s an easy call.
“I hard-boiled a bunch of eggs and don’t know how long ago.” Hard-boiled eggs last only 1 week refrigerated — significantly less than raw eggs. This is because the cooking process removes the protective membrane just inside the shell that helps protect raw eggs. If you’re uncertain whether it’s been more than 7 days since hard-boiling, discard.
When to Take Food Safety More Seriously
Most healthy adults recover from food poisoning caused by bad eggs (primarily Salmonella) within a few days without medical treatment — symptoms include nausea, vomiting, diarrhea, stomach cramps, and fever, typically appearing 6–48 hours after eating contaminated food.
Seek medical attention if:
- Symptoms are severe or worsen after 48 hours
- There is blood in stool or vomit
- High fever (above 102°F / 38.9°C)
- Signs of serious dehydration (unable to keep fluids down, very dark urine, dizziness)
- The affected person is pregnant, elderly, immunocompromised, or a young child — these groups face higher risk of serious complications from Salmonella and should contact a healthcare provider early
Quick Reference: How to Tell If Eggs Are Still Good
| Check | Method | Reliability | Best for |
|---|---|---|---|
| Julian date | Find 3-digit number on carton | ✅✅✅ High | First check before anything else |
| Float test | Bowl of cold water | ✅✅ Medium | Approximate age indicator |
| Smell after cracking | Crack into separate bowl | ✅✅✅ High | Definitive safety check |
| Visual check | Look at yolk and white | ✅✅ Medium | Quality check, not just safety |
| Shake test | Hold to ear and shake | ✅ Low | Rough indicator only |
FAQ
Q: Can you eat eggs after the sell-by date?
Yes, frequently. The sell-by date is a retailer’s inventory management tool, not a food safety cutoff. The USDA states eggs remain safe for 3–5 weeks after purchase when properly refrigerated. Use the Julian date (the three-digit number on the carton) to get a more accurate picture of how old the eggs actually are — the 45-day guideline from pack date is more useful than any sell-by date.
Q: Does a floating egg mean it’s bad?
No — floating means the egg is older, because moisture has evaporated through the shell and the internal air cell has grown. The USDA acknowledges that a floating egg may still be perfectly safe. Crack it into a separate bowl and smell it: no smell = safe to use, sulfurous smell = discard.
Q: How long do eggs last in the fridge?
Raw eggs in their shells: 3–5 weeks after purchase (or up to 45 days from pack date). Hard-boiled eggs in shells: 1 week. Hard-boiled eggs peeled: 5 days in an airtight container with water. Raw egg whites: 2–4 days. Raw egg yolks: 2–4 days covered with water. Frozen whole eggs (beaten): up to 1 year.
Q: What does a bad egg smell like?
Sulfurous, like rotten eggs (which is exactly what it is). Sometimes described as ammonia-like or like hydrogen sulfide. It’s an immediate, distinctive, unambiguous smell — you will not have to wonder whether what you’re smelling is “off.” If you’re asking yourself whether it smells bad, it probably doesn’t. If it smells bad, you know it immediately.
Q: Is it safe to use eggs past the expiration date?
Often yes. The expiration date is not the same as a food safety deadline. Properly refrigerated eggs commonly remain safe and usable for weeks beyond printed dates. The Julian date, float test, and smell test together give you a much more accurate picture than the expiration date alone. When in doubt, crack into a separate bowl, smell, and visually inspect — that’s your most reliable answer.
Q: Why do hard-boiled eggs last a shorter time than raw eggs?
The cooking process damages the protective membrane just inside the shell and removes some of the shell’s natural antimicrobial properties. Raw egg shells, while porous, have structural integrity that slows bacterial entry. Once cooked, the egg is more vulnerable to surface bacteria, and the yolk — now fully exposed if peeled — is particularly susceptible. Always refrigerate hard-boiled eggs and use within a week.
The Honest Bottom Line
Eggs are one of the most economical, nutritious, and versatile proteins in any family kitchen — and one of the most misunderstood when it comes to freshness and safety. The date system on cartons is genuinely confusing, the float test is partially misrepresented across the internet, and the result is that millions of perfectly good eggs get thrown away every year while occasionally a questionable one makes it into someone’s recipe.
The system that actually works is simple: check the Julian date first, use the float test as a rough age indicator, and make every final safety call by cracking into a separate bowl and smelling. The separate bowl habit is the one that actually protects your family and your recipes — and it costs you nothing.
For the broader question of building a kitchen that wastes less and costs less, our pantry staples guide covers everything worth keeping on hand — including how to store eggs properly alongside everything else. And if you’re building weekly routines around smart food management, our how to save money on groceries guide connects all of it into a system.
References
- USDA Agricultural Marketing Service. Shell Eggs from Farm to Table. ams.usda.gov
- USDA Food Safety and Inspection Service. Shell Eggs from Farm to Table — Storage and Handling. fsis.usda.gov
- FoodSafety.gov. FoodKeeper App — Eggs Storage Times. foodsafety.gov
- Centers for Disease Control and Prevention. Salmonella and Eggs. cdc.gov
- FDA. Refrigerator & Freezer Storage Chart — Eggs. fda.gov