Flour is the classic sauce thickener, but it clouds a sauce, needs cooking to lose its raw taste, and does not suit gluten free cooking. This calculator replaces flour with purer starches, giving the matching amount of cornstarch, arrowroot, tapioca, or potato starch for the same sauce.
Enter the amount of thickener you have and pick which one it is. The tool uses a simple base: sixteen grams of flour thickens two hundred fifty millilitres of liquid, and every other starch is scaled from that same liquid amount, so your sauce keeps the same body.
Example: thirty two grams of flour thickens five hundred millilitres of liquid, which equals sixteen grams of cornstarch, sixteen grams of arrowroot, twenty grams of tapioca starch, or eighteen grams of potato starch. For a clear gravy, pick cornstarch or arrowroot over flour.
Tip: for a gluten free swap, cornstarch is the easiest choice. It is widely sold, it thickens at half the weight of flour, and it leaves a clear, clean tasting sauce.
Tip: add starch thickeners at the end of cooking. They thicken fast and break down under long hard boiling, so stir them in once the sauce is nearly done.
Tip: taste before you thicken more. A sauce thickens as it cools, so stop a little thinner than your target and let the pot rest for a few minutes before judging it.
Common question: Can I use flour and cornstarch together? Yes, and many cooks do. A little flour gives body and a little cornstarch adds shine, and the blend forgives small measuring slips.
Common question: Does potato starch taste different? Barely, when used in sauce amounts. It thickens well and stays fairly clear, though it can turn gluey if it is boiled hard, so keep the heat gentle.
Common question: Why is my roux sauce lumpy? The flour was not cooked into the fat first, or the liquid went in too fast. Cook the flour in fat for a minute, then add warm liquid slowly while whisking without stopping.
Measuring by weight is the single best habit for swaps like these. Cups pack differently every time, while grams stay exact, and exact amounts are what make a substitute behave like the original ingredient.
Test every swap in a small batch first. A half recipe shows you the texture and flavour change without risking a full cake or a full pot of jam, and a small test teaches you faster than any article can.
Write the swap that worked on the recipe card. Your oven, your flour brand, and your pans all shift results a little, and your own notes turn a general calculator into a personal guide that fits your kitchen.
This tool runs fully in your browser, so nothing you type is sent to a server. There is no account and no sign-up, and your recipe amounts never leave your own device.
Adjust to your own taste once you know the base ratio. A little more liquid for a softer crumb, or a little less for a firmer set, is a fair change once the standard swap works well.
Store dry substitutes mixed and labelled. A jar of self-raising flour or cake flour mix, dated and sealed, saves measuring time on busy baking days and keeps the ratio right.
Bookmark this tool and use it whenever a recipe calls for something your pantry lacks. A good substitute keeps dinner on track, and the calculator keeps the swap honest.
This tool is free to use as often as you like. Run it for each recipe you adapt, and let it carry the conversion maths while you focus on the cooking itself.