Most baking recipes are written in the language of count: 2 large eggs, 4 large eggs, sometimes 6 medium eggsfor the European cookbook on your shelf. The assumption is that an egg is a known quantity. It isn't. A “large” egg in the United States is anywhere between 49 grams and 56 grams without its shell — a fourteen-percent spread on what should be a fixed unit.
For a recipe that calls for four large eggs at the lower end of that range — 196 g of egg — the same recipe with four eggs at the upper end is 224 g. That's nearly an extra egg's worth of protein, water, and fat in the bowl. In a cake or custard, you'll feel it.
The USDA size grid, in numbers
American egg cartons are graded by minimum total weight per dozen. The actual single-egg weight (without shell) lands in these ranges:
- Peewee — ~30 g
- Small — ~38 g
- Medium — ~44 g
- Large — ~50 g
- Extra-large — ~56 g
- Jumbo — ~63 g+
The convention in modern American recipe writing is “large” — 50 g per egg, 200 g for a four-egg cake. European recipes typically assume medium(M, ~44 g), so a French cookbook calling for “6 eggs” expects 264 g of egg, not 300 g.
The fix every working baker uses
Crack and weigh. Crack the eggs into a separate bowl, weigh the bowl on a tared scale, and adjust to the recipe's expected gram weight by adding more or removing some. For a four-large-egg recipe (200 g), if your three eggs already weigh 165 g, the fourth needs to contribute 35 g — pour the fourth in slowly until you hit 200 g and stop.
This sounds fussy until you do it once and notice how forgiving cakes become. Custards stop weeping. Cakes stop sinking in the centre. Cookies stop spreading inconsistently.
Whites and yolks separately
For meringues, French buttercream, sponge cakes — anywhere the recipe calls for a specific number of whites or yolks — the variation is even worse. Yolks are the more variable component (yolk size correlates with hen age), so a recipe calling for “6 yolks” can deliver 90 g or 120 g without any of the eggs being unusual.
- 1 large egg white ≈ 30 g
- 1 large egg yolk ≈ 18 g
- 1 large egg, no shell ≈ 50 g
Mismatched cartons
If your carton is labelled medium and the recipe calls for large, you don't need to chase the exact size — you need to chase the gram weight. For four large eggs (200 g) using medium eggs (~44 g each), use four eggs and add a fifth white plus an extra spoonful of cream or oil to make up the missing fat. Or, much simpler: weigh. The scale doesn't care what size the carton claims.
Pairing with the rest of the toolkit
The same logic that applies to flour (your flour is heavier than the recipe thinks) applies to eggs: count is a proxy for weight, and the proxy fails. The ingredient converter has gram-per-unit entries for whole eggs, whites, and yolks, calibrated to the same large-egg standard you can use as a target.