The thirty second method
Crack the egg into a small bowl or ramekin, beat it with a fork until the white and yolk are completely smooth, then measure out what you need. One large egg beats out to about 3 tablespoons, so half an egg is about 1.5 tablespoons. Pour the measured half into your recipe and discard or save the rest. That is the whole technique, and it works for every odd egg count you will ever meet.
Beating matters. An unbeaten half egg is mostly white or mostly yolk depending on your luck, and whites and yolks do different jobs in baking. Beat first, then measure, and the half you use has the right composition.
The egg halving chart
| Original | Halved |
|---|---|
| 1 egg | 1.5 tablespoons beaten egg |
| 2 eggs | 1 egg |
| 3 eggs | 1 whole egg plus half of a second beaten egg |
| 4 eggs | 2 eggs |
| 5 eggs | 2 whole eggs plus half of a third beaten egg |
Even counts halve cleanly; odd counts need one beaten egg. For 3 eggs halved (1.5 eggs), add 1 whole egg to the bowl, then beat a second egg separately and measure in half of it, about 1.5 tablespoons. For 5 eggs halved (2.5 eggs), same idea one step up. The recipe scaler flags egg lines when scaling so they do not slip past you as decimals.
Halving separated whites and yolks
Recipes that call for separated eggs need the white and yolk math separately. One large egg white is about 2 tablespoons, so half a white is about 1 tablespoon. One large yolk is about 1 tablespoon, so half a yolk is about 1.5 teaspoons. Separate first, then beat each part smooth and measure.
Whipped whites deserve a warning. Halving a meringue or angel food style recipe changes the foam physics: less volume whips faster and can go from soft peaks to overbeaten in seconds. Watch it closely rather than trusting the original timing. If the recipe depends entirely on whipped egg structure, consider making the full recipe instead of halving.
When the egg math gets silly
There is a point where precision stops paying. Halving a recipe that calls for 1 egg leaves you measuring 1.5 tablespoons of beaten egg into a small batch where a little extra egg barely matters. In forgiving dishes like pancakes, muffins, and quick breads, rounding to the nearest sensible amount (a generous half egg, or even a whole small egg) works fine.
In fussy baking, custards, and anything where the egg is structural, do not round. Measure the 1.5 tablespoons. And if halving leaves you fighting over fractions of an egg in a recipe with five eggs and three separated whites, that is the recipe telling you to find a smaller recipe rather than forcing the math.
Substitutes for awkward halves
Two shortcuts exist for cooks who hate beating and measuring. Pasteurized liquid egg product pours and measures like a liquid, so half an egg is simply 1.5 tablespoons from the carton, no cracking required. And for vegan baking, the standard egg replacers (flax eggs, commercial replacers) scale in fractions without complaint, since they were liquids to begin with.
The carton trick has a bonus: the leftover half egg keeps. Beaten egg holds in the refrigerator for a day, so the unused 1.5 tablespoons can scramble into tomorrow's breakfast instead of going down the drain.
Why eggs matter so much in baking
Eggs do four jobs at once: structure from the proteins, richness and emulsification from the yolk fat, leavening from beaten air, and moisture. That is why getting the egg count right matters more than getting the flour right to within a tablespoon. When a halved cake fails, the egg line is the first suspect, before the flour, the leavening, or the oven. Measure the eggs carefully and the rest of the halving math is forgiving.