Pasta Water Amount Calculator
Calculate the right amount of water and salt for cooking pasta perfectly every time.
Works for any pasta type and quantity.
Pasta Water Calculator helps you get the correct ratio of water and salt so pasta cooks evenly and tastes great.
The Standard Rule: Professional cooks follow a classic ratio: 1 liter of water per 100 g of pasta (or about 4 cups of water per 3.5 oz). This gives the pasta enough room to move freely while boiling, preventing it from sticking together.
Why so much water? Pasta releases starch as it cooks. Too little water causes the starch to concentrate quickly, making pasta gummy and sticky. Plenty of water keeps the temperature stable when pasta is added, and dilutes the starch so pasta stays separate and toothsome.
Salt, the step people skip: Pasta water should taste pleasantly salty, like mild seawater. The working range is 7 to 12 grams of salt per liter of water, and 10 g per liter is the standard used by the pasta water ratio calculator and the pasta portion pages. Most of it goes down the drain; only a small fraction is absorbed, which is why the water tastes far saltier than the pasta ends up.
Weigh it if you can. A tablespoon of table salt is about 18 g and a tablespoon of Diamond Crystal kosher is about 9, so a recipe that says “a tablespoon” is off by a factor of two depending on which box is open.
This is the only opportunity to season the pasta itself. Nothing you do afterwards reaches the inside.
Pasta types and water needs:
- Long pasta (spaghetti, linguine, fettuccine): standard ratio applies
- Short pasta (penne, rigatoni, fusilli): same ratio; these cook faster
- Fresh pasta: cooks in 1–3 minutes; needs the same water volume
- Stuffed pasta (ravioli, tortellini): needs extra room — increase water slightly
Pot size tip: Use the largest pot you have. The water should not fill more than two-thirds of the pot, or it will boil over.
When to add pasta: Always wait for a full rolling boil — not just small bubbles. Add pasta all at once and stir immediately for the first 30 seconds to prevent sticking.
Example: For 500 g (about 1 lb) of spaghetti, use 5 liters (about 21 cups / 1.3 gallons) of water and add 35–50 g of salt (about 2–3 tablespoons). Bring to a boil, then cook per package directions.
This calculator handles metric (grams/liters) and imperial (oz/cups) quantities.
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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