Béchamel and Cheese Sauce Calculator
Choose the dish and how many people for the sauce quantities.
Answer
800ml milk, 50g butter, 50g flour
Weigh out
What to do
- 1Melt 50g butter, stir in 50g flour and cook for 2 minutes.
- 2Add 800ml milk a splash at a time, beating smooth between each addition.
- 3Simmer gently for 5 minutes, stirring, until it coats the back of a spoon.
- 4Season with salt, pepper and a scrape of nutmeg.
Next step
Worth knowing
- Enough to spread between layers and cover the top.
- Béchamel is a roux plus milk. Equal butter and flour, then milk added slowly.
- Take the pan off the heat before the cheese goes in. Boiled cheese turns stringy and greasy.
- A bay leaf and a few peppercorns warmed in the milk make a noticeable difference for very little effort.
Source: Classic sauce ratios as taught in standard UK cookery references · Reviewed 2026-09-10 · Guidance version 1.0.0
Reference and detail
Different dishes need different amounts
Lasagne needs enough to cover every layer generously; a gratin topping needs far less. Guessing is why lasagne so often comes out dry at the edges.
Take it off the heat before the cheese
Boiled cheese goes stringy and releases its fat. Off the heat and stirred in at the end, it stays smooth.
Season it more than you expect
Milk-based sauces need salt, pepper and a scrape of nutmeg to taste of anything. Taste it before it goes into the dish, not after.
Questions and answers
Questions about béchamel sauce quantities
How much béchamel sauce do I need per person?
Enter the number of people and the dish above for a total. A pouring sauce over fish or gammon needs the least per person; a dish like macaroni cheese or cauliflower cheese, where the sauce is the point, needs considerably more.
What is the difference between a thin and a thick béchamel?
The ratio of roux to liquid. A thin, pouring béchamel uses the least butter and flour per 500ml of milk; a thick béchamel for a fish pie base or croquettes uses roughly double, and sets much firmer once cooled.
Why has my béchamel gone lumpy?
The milk was added too quickly, or too cold, before the roux was smooth. Add the milk gradually, off the heat, whisking continuously, and it will come back together.
How much cheese do I add to a cheese sauce?
Enter the volume of béchamel and the dish above for a suggested amount per litre. Cauliflower cheese and macaroni cheese both take a generous quantity, since the cheese carries much of the flavour.