For most home sauces, a good starting point is 1–2 tablespoons of cornstarch per 1 cup (240 ml) of liquid , mixed first into a cold slurry.

Quick Scoop: Exact Amounts

Use this per 1 cup of sauce (about 240 ml):

  • Thin, light sauce: 0.5 tablespoon cornstarch.
  • Medium, “just right” sauce: 1 tablespoon cornstarch.
  • Thick, gravy‑style sauce: 1.5–2 tablespoons cornstarch.

Always start on the low end; you can whisk in more slurry if it’s still too runny.

How to Use It (So It Isn’t Lumpy)

  1. In a small bowl, mix cornstarch with cold water, broth, or milk in about a 1:1 to 1:2 ratio (e.g., 1 tablespoon cornstarch + 1–2 tablespoons cold liquid) to make a smooth slurry.
  1. Bring your sauce to a simmer.
  1. Slowly drizzle in the slurry while whisking constantly.
  1. Let it bubble for 30–60 seconds; it finishes thickening as it heats.
  1. If still too thin, repeat with a little more slurry.

Handy Rule of Thumb

  • Everyday use: 1 tablespoon cornstarch per cup for most sauces.
  • When converting a flour‑thickened recipe, use about half as much cornstarch as flour (e.g., if the recipe says 2 tablespoons flour, use 1 tablespoon cornstarch).

If you’re unsure how much liquid you actually have in the pan, treat it as a guess, start small, and add slurry gradually until the texture feels right.

Information gathered from public forums or data available on the internet and portrayed here.