What is a typical custard ratio?

A typical home pouring-custard ratio is about 3 whole eggs per 600ml of milk, with 2-3 tablespoons of caster sugar and a teaspoon of vanilla extract — this gives a smooth, pourable custard with good body. There is no single official ratio: richer recipes use yolks rather than whole eggs (Delia Smith's "Proper Custard" uses 6 egg yolks per 570ml of cream, and BBC Good Food uses 4 yolks across roughly 900ml of milk and cream). Switching from whole eggs to yolks changes the count because yolks alone are the thickening, enriching part. Whichever ratio you start from, custard scales linearly — double the dairy, double the eggs and sugar.

Should I use whole eggs or just yolks?

Whole eggs give a lighter custard that sets firmer — good for baked custards and custard tarts. Egg yolks alone produce a richer, silkier, more golden custard — perfect for creme anglaise and pouring custard. For a balanced approach, use a mix: 2 whole eggs plus 2 extra yolks per 600ml for the best of both worlds.

Why does my custard curdle?

Curdling happens when the eggs get too hot too quickly. To prevent this: temper the eggs by gradually adding hot milk to them while whisking (not the other way round), cook on a gentle heat stirring constantly, and never let it boil. If cooking on the hob, the custard is ready when it coats the back of a wooden spoon and a line drawn through it holds. Remove from heat immediately.

Can I make custard with cream instead of milk?

Yes, replacing some or all of the milk with single or double cream makes a richer custard. A common ratio for creme anglaise is 300ml milk and 300ml double cream with 6 egg yolks. For a baked custard, half-and-half milk and single cream works well. Pure cream custard is very rich and is typically reserved for creme brulee.

How do I thicken custard without cornflour?

Traditional custard thickens from the egg proteins coagulating when heated gently. More eggs will give a thicker custard. If you prefer using cornflour for reliability, add 1 tablespoon per 600ml of milk — this creates a more stable custard that is less likely to curdle and is closer to a creme patissiere in consistency.

Custard Ratio Calculator — Free Online Tool

How We Calculate This

This calculator takes a typical home pouring-custard ratio of 3 whole eggs per 600ml of milk as its baseline (in the range used by Delia Smith and BBC Good Food, who use 6 and 4 egg yolks respectively per roughly 600-900ml of dairy), and scales it linearly to your chosen milk volume. The richness setting adjusts the egg count: light uses 2 eggs, standard uses 3, and rich uses 4 per 600ml of milk. You can override the baseline eggs, sugar and reference volume in Advanced Options.

The volume you enter is the milk (or milk-and-cream) base — the eggs and sugar are added on top of it, so the finished custard is a little larger than the figure you type. Sugar is adjusted proportionally, with lighter custards using less sugar to keep the flavour delicate, and vanilla is suggested at approximately 1 teaspoon per 600ml batch. Custard sets from the egg proteins coagulating, so cook it gently and stir constantly to avoid curdling — see the FAQs below.

Frequently Asked Questions

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.