The 1-10-100 rule
Italian cooking has a beautifully simple rule for pasta water: for every 100 grams of pasta, use 1 litre of water and 10 grams of salt. That is the 1-10-100 rule, and it scales perfectly, whether you are cooking 250 grams for two people or a kilo for a crowd. The calculator on this page applies it to any weight you enter, so 500 grams of pasta needs 5 litres of water and 50 grams of salt, which is about three tablespoons of coarse salt. The rule looks generous, especially the water, but each part of it has a reason, and understanding those reasons is what separates good pasta from sticky, bland pasta.
Water matters because pasta releases starch as it cooks, and in too little water that starch concentrates, making the pasta gummy and the water cloudy and thick. Plenty of water keeps the pasta moving freely, lets it cook evenly, and dilutes the starch enough that the pieces do not glue together. Salt matters because pasta absorbs water as it cooks, and that water is its only chance to be seasoned from the inside: unsalted pasta tastes flat no matter how good the sauce is, because sauce coats the outside while the pasta itself remains bland. Ten grams per litre makes the water taste like the sea, which sounds dramatic but is exactly right once diluted by the pasta's absorption.
Why so much water?
The large water volume also keeps the temperature stable. When pasta goes into a pot, it cools the water, and a small pot can drop below boiling for minutes, leaving the pasta to soak rather than cook, which produces a soft, uneven texture. A large pot of vigorously boiling water recovers quickly, so the pasta cooks at a consistent temperature from start to finish. This is also why the pot should be the largest you own, not the one that just fits: pasta needs room to move, and a crowded pot is a sticky pot. Stirring in the first minute, when the starch is stickiest, matters as much as volume, so stay with the pot at the start rather than walking away.
There is a fashionable counter-argument that pasta can cook in much less water, and it is technically true: pasta cooked in a small amount of water, stirred constantly, cooks fine and produces very starchy water that is excellent for sauces. But that method demands attention and stirring, and it punishes inattention with sticking, while the classic large-pot method is forgiving and reliable for everyday cooking. For most home cooks, the classic rule wins on consistency, and the calculator's amounts are built around it. If you do try the low-water method, reduce the water but keep the salt proportion, about 10 grams per litre of whatever water you use.
Salt: type, timing, and taste
Salt type changes measurement, not the rule, because the rule is by weight. Ten grams of fine table salt, coarse sea salt, and kosher salt all weigh ten grams, but they occupy different volumes, so a tablespoon of one is not a tablespoon of another. Weighing salt on a kitchen scale is the reliable method, and it is why the calculator gives grams first. If you must use spoons, remember roughly that 10 grams is about two teaspoons of fine salt or about one tablespoon of coarse salt, but check your own salt once with a scale, because brands vary. Timing is simple: salt after the water boils, so it dissolves fast and does not pit the pot, and before the pasta goes in, so the pasta cooks in seasoned water from the first second.
One persistent myth is that oil in the water stops sticking. It does not, in any meaningful way, because oil floats on top while pasta cooks below, and it can actually hurt the final dish by coating the pasta and stopping sauce from clinging. Stirring, plenty of water, and not overcooking are what prevent sticking, and a good sauce, tossed with the pasta and a splash of starchy pasta water, finishes the job. Another myth is that rinsing cooked pasta helps: rinsing washes off the starch that helps sauce cling, and it cools the pasta, so the only time to rinse is for cold pasta salads, where you want the pieces separate and cool anyway.
Portions, shapes, and timing
A standard portion is about 100 to 125 grams of dried pasta per person for a main course, and 75 to 100 grams for a starter or a side, which means the calculator's 500-gram preset serves four mains comfortably. Long shapes such as spaghetti and linguine need a tall pot so they can bend in as they soften, while short shapes such as penne and fusilli are more forgiving of pot shape but trap sauce in their ridges and tubes, which is part of their charm. Fresh pasta cooks in a fraction of the time, two to four minutes, and still benefits from the same water and salt ratio, though its delicate texture means gentler stirring.
Cooking time should come from tasting, not just the packet. Start tasting two minutes before the packet time, and drain when the pasta is al dente, tender with a slight bite in the centre, because it will continue cooking for a minute in the hot sauce. Undercooking slightly, then finishing the pasta in the sauce with a splash of pasta water, is the professional technique, and it produces a dish where pasta and sauce taste like one thing rather than two. The starchy water is liquid gold here: its dissolved starch emulsifies with oil and cheese, turning a thin sauce silky, which is why saving a cup before draining is a habit worth forming.
Sauce, serving, and leftovers
Once drained, pasta should meet sauce immediately, in the pan, not sit in a colander while sauce waits in another pan. Toss for a minute over heat with sauce and pasta water, so the pasta absorbs flavour and the sauce thickens around it, then serve on warm plates, because pasta cools fast. Leftovers reheat best in a pan with a splash of water, which loosens the sauce without making it greasy, while microwaving tends to dry the edges. And if you regularly cook for one, the calculator still helps: 125 grams needs 1.25 litres of water and 12.5 grams of salt, small numbers that are easy to get wrong by eye.
| Pasta | Water | Salt | Serves (mains) |
|---|---|---|---|
| 250 g | 2.5 L | 25 g | 2 |
| 500 g | 5 L | 50 g | 4 |
| 1,000 g | 10 L | 100 g | 8 |
- 1 litre of water and 10 g of salt per 100 g of pasta.
- Weigh salt — spoon volumes vary by salt type.
- Salt after boiling, before pasta goes in.
- Stir in the first minute; skip the oil.
- Save a cup of pasta water for the sauce.
Pasta is simple food, and simple food rewards getting the basics right. Plenty of water, enough salt, a taste before draining, and a quick toss in the sauce, and the calculator's numbers take care of the rest.
Whole-wheat and legume pastas follow the same water and salt rule, though their cooking times and textures differ: whole-wheat pasta takes a little longer and tastes nuttier, while chickpea and lentil pastas cook faster and foam more, so they benefit from a larger pot and closer watching. Gluten-free rice and corn pastas are the most fragile, going from firm to mushy in a minute, so tasting early matters even more. Whatever the type, the ratio stays the same, one litre and ten grams per hundred grams, which is why the calculator works for every pasta in the pantry, not just white semolina shapes.