Egg Size Converter

Egg sizes vary. A UK Large egg weighs around 68 g in the shell and holds about 61 g of usable content; a Small egg is only 48 g in the shell and 43 g of content. That means three Large eggs give you roughly the same volume as four Small eggs — and if you swap them one-for-one, a sponge cake or a Yorkshire pudding batter will end up noticeably different. This converter tells you exactly how many eggs of one size are equivalent to any number of another size, using average UK grade weights.

It's aimed at home bakers, anyone working from an older recipe that just says "eggs", and cooks who buy Small eggs from the garden or a local farm and need to translate a supermarket recipe. Use it when the eggs in your fridge don't match the size the recipe assumes.

How the calculation works

We use the standard UK/EU grade weights: Small (48 g in shell, 43 g content), Medium (58 g / 52 g), Large (68 g / 61 g) and Extra Large (78 g / 70 g). The formula is new count = (original count × original content) ÷ new content. The result is rounded to one decimal place so you can see how far from a whole number you are, along with the total grams of usable egg content for anyone who prefers to weigh.

A worked example

A recipe from your mother's old cookbook calls for four Medium eggs. All you have in the fridge is a box of Large. The total egg content needed is 4 × 52 = 208 g. Divided by the 61 g content of a Large egg, that's 3.4 Large eggs. In practice: use three Large eggs whole, plus beat a fourth and add half of it (roughly 30 g). For a forgiving family bake, three Large eggs will be fine.

Going the other way: your Yorkshire pudding batter uses three Large eggs (183 g of content) and today you only have Small eggs. 183 ÷ 43 = 4.3 Small eggs. Use four and add a splash of extra milk to bring the batter to the right consistency.

Why this matters

The four grades sold in UK supermarkets span roughly 30 g of usable egg content per egg — the difference between a Small and an Extra Large. Multiply that across four or five eggs and a cake batter can be off by more than 100 g of liquid. That's enough to change the texture from tender and moist to dry and dense, or from a light sponge to a heavier pound cake. Egg-heavy recipes like Genoise, angel cake and pavlova are the most sensitive; everyday bakes are more forgiving.

Limitations to be aware of

The grade averages are exactly that — averages. Individual eggs vary by 5–10% within a grade, and free-range or garden eggs can vary more. If precision really matters, weigh your eggs into the bowl and stop when you reach the total gram figure this calculator gives you. The ratio of yolk to white is also fairly consistent within a grade, so if a recipe calls for "3 egg yolks", scaling by content works reasonably well but is less exact than for whole eggs.

Common mistakes

• Assuming "eggs" means Large in every recipe. Modern UK books do, but older cookbooks often meant Medium.
• Substituting one small for one large — the difference is around 20% of usable content, enough to change a sponge.
• Not adjusting other liquids when swapping to smaller eggs — the batter can end up too stiff.
• Cracking eggs directly into the bowl when weighing — a bad egg contaminates the batch. Crack each one into a separate small bowl first.
• Using fridge-cold eggs in a whisked sponge — cold whites don't reach full volume. Bring to room temperature first.
• Forgetting about yolk-to-white ratio — a heavier egg has proportionally more white than a smaller one, which occasionally matters in enriched doughs.

Related tools: Recipe Scaler · Grams to Cups · Butter Conversion · Cake Tin Converter