Custard Ratio Calculator
Calculate egg yolks, cream, milk, and sugar for crème brûlée, pastry cream, crème anglaise, or baked flan.
Scales to the finished volume you want.
Understanding Custard Ratios
Custard is an egg-thickened liquid — the proteins in egg yolks coagulate when heated, transforming cream or milk into a smooth, rich sauce or set dessert. The ratio of eggs to liquid controls texture, from barely-set panna-cotta-like creaminess to firm sliceable custard.
Types of Custard and Their Ratios
| Type | Per 250 ml of milk and cream | Use |
|---|---|---|
| Pouring custard (crème anglaise) | 3 yolks, 50 g sugar | Ice cream base, sauce |
| Crème brûlée | 4 yolks, 55 g sugar | Individual ramekins, blowtorched top |
| Pastry cream (crème pâtissière) | 4 yolks, 60 g sugar, 25 g starch | Éclair filling, tart base |
| Baked custard / flan | 2 whole eggs + 1 yolk, 50 g sugar | Sliceable, firm texture |
Notice that the ratios are quoted per 250 ml of liquid, which is the traditional way to write them, but that is not how much custard you end up with. Yolks and dissolved sugar take up room too. Start with 250 ml of cream and milk for a crème anglaise and you will finish with something closer to 330 ml; a crème brûlée, with more yolks and more sugar, lands nearer 350 ml.
The calculator works backwards from the amount you actually want, so the yield you type is the yield you get. That matters most for brûlée, where you are filling a fixed number of ramekins and a 40% overrun means a bowl of leftover custard and no room in the water bath.
The Role of Each Ingredient
- Egg yolks: Lecithin and proteins provide richness and thickening power.
- Heavy cream: Fat content makes the custard silky. Use 35%+ fat cream for best results.
- Milk: Lightens the texture. Using all cream makes it too heavy.
- Sugar: Sweetens and slightly raises the coagulation temperature, giving a smoother result.
- Salt: A small pinch enhances all other flavors dramatically.
- Vanilla: Infuse a split bean in the warm cream before straining for best flavor.
Temperature Is Everything
Custard proteins set at around 82–85°C (180–185°F). Above 90°C (194°F), the eggs scramble and the custard curdles. Always cook over gentle heat and stir constantly for stirred custards. For baked custards, use a water bath (bain-marie) to ensure gentle, even heat.
Test for Doneness
A properly cooked stirred custard coats the back of a spoon — draw your finger across it and the line should hold cleanly. Baked custard is done when the edges are set but the center still has a slight wobble.
Storage
Custard keeps refrigerated for up to 3 days. Press plastic wrap directly onto the surface to prevent a skin from forming.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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