Firstly, and if the eggs are packaged, you must check their expiry date. Most eggs these days are packaged so it is easy to define their suitability.

If there is no date however, you can check an egg’s freshness by placing it under water.

As time passes, the egg loses water from its shell and its air chamber expands. The less fresh it is, the lighter it becomes. In practice, a stale egg will float up to the surface if you place it under water, while a fresh egg will remain on the bottom.