How to Use the Egg Freshness & Storage Calculator
As an egg ages, moisture and carbon dioxide slowly escape through its shell, causing the air cell at the rounded end to grow larger. The water test relies on this: dropping an egg into water and watching how it sits reveals a rough estimate of freshness. This calculator combines your water test result with the number of days since purchase to estimate a freshness level, remaining storage days, and a suitable cooking use.
An egg that sinks and lies flat has a small air cell and is very fresh, while one that floats completely has a larger air cell and is well past its prime. Keep in mind the water test is only a reference method — actual freshness also depends on storage temperature, handling, and shell condition.
As a general guideline, refrigerated eggs are typically fine for about 3 to 5 weeks from the purchase date, but this is not an absolute rule — it's a general food-safety guideline. If an egg smells off or looks discolored when cracked, don't use it regardless of what this calculator shows, and always make the final call yourself after checking it directly.
Frequently Asked Questions
As an egg ages, its air cell grows larger from moisture loss through the shell, making it float higher in water. Eggs that sink and lie flat are freshest, while those that float are older.
An egg that floats completely to the surface is generally considered past its prime and best discarded, as a general food-safety guideline. Still, check smell and appearance yourself before deciding.
As a general guideline, eggs are typically safe for about 3 to 5 weeks after purchase when refrigerated, though this varies by storage temperature and handling — use this calculator as a reference only.