Rice Water Ratio Calculator (By Type and Method)
Rice Water Ratio Calculator (By Type and Method)
Water per cup of rice for twelve kinds of rice and five cooking methods, with the absorbed water computed from USDA composition and the boiled-away water separated out — which is why no two published ratios agree, and why the ratio falls as the pan fills.
Rice and water
One US cup of white long-grain rice, open pan with a tight lid, USDA’s own cooked moisture, nothing soaked
Hydration from a mass balance, plus evaporation from the pan
- m dry
- the dry rice, in grams — from the volume you measured and the published bulk density of that rice
- w0
- the moisture content of the raw rice, from USDA FoodData Central
- w1
- the moisture content you want it to finish at. USDA’s own cooked entry, shifted up or down by the texture you chose
- r × t
- water boiled away: a rate in grams per minute times the cooking time. Depends on the pan and the lid, not on the rice
- soak
- water the grain already took up if you soaked and drained it — about 0.2 g per gram of dry rice
Worked example
One US cup of white long-grain rice, open pan with a tight lid, USDA's own cooked moisture, nothing soaked
A US cup of raw long-grain white rice is 185 g (USDA 169756), so the bulk density is 185 / 236.59 = 0.7819 g/mL
It goes from 11.6% water to 68.5% water (USDA 169757), so it must absorb 185 × [(1 − 0.116)/(1 − 0.685) − 1] = 334 g
At 8 g a minute for 17 minutes, another 136 g boils away
Total 470 g of water, which is 471 mL — 1.99 cups per cup, against the 2.00 USA Rice publish
And it finishes as 519 g of cooked rice, 3.29 cups — USA Rice say three
Every rice, and where each number comes from
| Rice | g per US cup | Raw water | Cooked water | Published ratio | Of which hydration | Implied boil-off, g/min | Minutes | Rinse / soak | Source |
|---|---|---|---|---|---|---|---|---|---|
| White, long grain | 185 | 11.6 % | 68.5 % | 2.00 | 1.42 | 8.1 | 17 | rinse | USDA 169756 raw and 169757 cooked; ratio USA Rice |
| White, medium grain | 185 | 11.6 % | 68.5 % | 1.50 | 1.42 | 1.2 | 17 | rinse | USDA long-grain composition; ratio USA Rice |
| White, short grain | 185 | 11.6 % | 68.5 % | 1.25 | 1.42 | negative — see the caption | 17 | rinse | USDA long-grain composition; ratio USA Rice |
| Basmati, white | 185 | 11.6 % | 68.5 % | 2.00 | 1.42 | 8.1 | 17 | rinse, soak | USDA long-grain composition; ratio USA Rice (US-grown basmati) |
| Jasmine, white | 185 | 11.6 % | 68.5 % | 2.00 | 1.42 | 8.1 | 17 | rinse | USDA long-grain composition; ratio USA Rice (US-grown jasmine) |
| Sushi rice (short-grain Japonica) | 185 | 11.6 % | 68.5 % | 1.25 | 1.42 | negative — see the caption | 20 | rinse, soak | USDA long-grain composition; ratio Cook’s Illustrated, 1 cup : 1¼ cups |
| Brown, long or medium grain | 185 | 11.8 % | 70.3 % | 2.25 | 1.54 | 3.9 | 43 | — | USDA 169703 raw and 169704 cooked; ratio USA Rice |
| Red rice (Camargue, Bhutanese, Wehani) | 185 | 11.8 % | 70.3 % | 2.25 | 1.54 | 3.9 | 43 | — | USDA brown-rice composition; no USDA entry for red rice |
| Wild rice (Zizania — not rice at all) | 160 | 7.9 % | 73.9 % | 3.00 | 1.71 | 6.8 | 45 | rinse | USDA 169726 wild rice raw and 168897 cooked; ratio USA Rice |
| Parboiled (converted) white | 185 | 10.0 % | 68.5 % | 2.25 | 1.45 | 9.4 | 20 | — | USDA long-grain composition; ratio USA Rice |
| Parboiled brown | 185 | 10.0 % | 70.3 % | 2.25 | 1.59 | 6.2 | 25 | — | USDA brown composition; ratio USA Rice |
| Arborio / carnaroli (risotto) | 200 | 11.6 % | 68.5 % | 4.00 | 1.53 | 23.3 | 25 | — | USDA long-grain composition; ratio USA Rice. Risotto is not an absorption method — see the note. |
Why the ratio falls as the pot fills — white long-grain, 8 g/min, 17 minutes
| Cups of dry rice | Water absorbed, g | Water boiled away, g | Total water, g | Ratio, cups per cup |
|---|---|---|---|---|
| 1 | 334 | 136 | 470 | 1.99 |
| 2 | 668 | 136 | 804 | 1.70 |
| 3 | 1,003 | 136 | 1,139 | 1.61 |
| 4 | 1,337 | 136 | 1,473 | 1.56 |
| 6 | 2,005 | 136 | 2,141 | 1.51 |
| 8 | 2,673 | 136 | 2,809 | 1.49 |
The same rice, four ways — Bob’s Red Mill’s own instructions for one product
| Method | Water per cup of rice | What changed |
|---|---|---|
| Stovetop | 1¾ cups | The reference |
| Multi-cooker at high pressure | 1¼ cups | Sealed. Half a cup less water, because half a cup less left the pan |
| Slow cooker | 2 cups | Hours with a lid that is not a tight lid. A quarter cup more |
| Oven, covered dish | Not published for this product | Longer than the stovetop and in a dish rather than a pan |
Rinsing and soaking, and what each actually does
| Step | What it changes | What it does to the water |
|---|---|---|
| Rinsing until the water runs clear | Removes loose surface starch and milling dust | Nothing measurable — but the grains leave the sieve wet, so drain them well or you have added water you did not count |
| Soaking 30 minutes, then draining | The grain takes up roughly 0.2 g of water per gram of dry rice, so it starts partly hydrated | Reduce the cooking water by about 37 g per US cup of rice, which is 0.16 cups |
| Soaking and NOT draining | Same hydration, but the soaking water is still there | Count the soaking water as part of your total and add only the rest |
| Not soaking a rice that wants it (basmati, sushi rice) | The outside hydrates and gelatinises before the middle does | Nothing — and this is the commonest reason a correct ratio still gives you rice that is wet outside and chalky inside |
Why there is no such thing as the water-to-rice ratio
The water you add does two different jobs, and every disagreement between published ratios is about the second one. Part of it soaks into the grain, and that part is a property of the rice and of how soft you want it. The rest boils away, and that part is a property of your pan, your lid and the cooking time — it has nothing to do with the rice at all. Separate them and the whole subject stops being contradictory.
The hydration part is calculable, and USDA has the numbers. FoodData Central publishes raw long-grain white rice at 11.6% water, 185 g per cup, and cooked long-grain white rice at 68.5% water, 158 g per cup. A mass balance on those two figures says a cup of dry rice must take up 334 g of water to get from one to the other, which is 1.42 cups, and finishes at 519 g — 3.29 cups of cooked rice, against the “3 cups” USA Rice publish. Two independent measurements, 9% apart, and neither is a rule of thumb.
The evaporation part is the whole spread. Take USA Rice’s published ratio for each rice, subtract the hydration the USDA composition demands, and divide by the cooking time: what comes out is between 1.2 and 9.4 grams of water a minute. That is what a covered saucepan at a bare simmer loses. It is also why a pressure cooker needs half a cup less water than a saucepan for the same rice — Bob’s Red Mill publish exactly that, three ratios for one product — and why a slow cooker needs a quarter cup more.
And it is why the ratio falls as the pot fills. Double the rice and you double the water it absorbs, but you do not double what boils off: the pan is the same pan. On the figures above, one cup of white rice wants 1.99 cups of water and eight cups want 1.49 each. Every single published ratio is therefore right for one quantity of rice and progressively wrong for every other, and nobody says so. America’s Test Kitchen demonstrated the limiting case from the other end: sealed in vacuum bags where nothing could evaporate, seventeen different varieties all cooked properly at one part water to one part rice.
Two rows of the table come out negative, and they are the most interesting rows. For short-grain white and for sushi rice, the ratio USA Rice publish is less water than USDA’s cooked entry contains. Neither is wrong. USDA measured one particular cooked rice at 68.5% moisture; short-grain rice at 1.25:1 comes out firmer than that, which is what short-grain rice is cooked for. The target texture is an input on this page rather than a constant precisely because there is no single correct cooked moisture content, and pretending otherwise is what makes every other rice calculator disagree with your dinner.
Rinsing, soaking, and the reason a correct ratio still fails. Rinsing removes surface starch and changes the water budget not at all, unless you drain badly. Soaking puts roughly a fifth of the dry weight of the rice into the rice before it ever meets the pan — about 37 g per cup, which you then subtract. But the real reason to soak basmati or sushi rice is that it hydrates the grain evenly, so the outside does not gelatinise while the middle is still dry. Rice that is simultaneously soggy and chalky is almost never a ratio problem.
For the cup that is not a cup — the Japanese go, the metric cup, the three different things British books have meant by the word — the US, UK and metric measures converter has all of them, and the cups to grams converter carries the densities. Risotto readers should note that arborio at 4:1 is not an absorption ratio at all: the stock goes in gradually, agitation pulls the starch out, and the number in the table is a total rather than an instruction.
Frequently asked questions
What is the water-to-rice ratio?
There is no single one, and the reason is worth thirty seconds. The water you put in a pan does two different jobs: some of it soaks into the rice, and the rest boils off. The soaking-in part depends on the rice and on how soft you want it — for white long-grain it works out at about 1.42 cups per cup, from USDA’s own measured moisture contents. The boiling-off part depends on your pan, your lid and the cooking time, and not on the rice at all. Add them and you get the ratio for your pot. USA Rice publish 2:1 for white long-grain, which is the sum for one cup in a saucepan.
Why do published rice ratios disagree with each other?
Because they are each correct for one pot, one quantity and one texture, and they do not say which. USA Rice publish 2:1 for long-grain white and 1.25:1 for short-grain; Tilda publish what they call 2:1 for basmati but mean two parts water to one part rice by weight, which is about 1.56:1 by volume; America’s Test Kitchen sealed seventeen varieties in vacuum bags so nothing could evaporate and found 1:1 hydrated all of them. None of those is wrong. They differ by the evaporation term and by the target texture, and this page separates the two so you can see which one you are arguing about.
How much does rice expand when cooked?
White long-grain roughly triples: USDA’s raw and cooked entries imply 3.29 cups of cooked rice from one cup dry, and USA Rice publish “3 cups”. Brown rice is the surprise — it absorbs more water and yields FEWER cups, 2.72, because cooked brown rice packs at 202 g per cup against 158 for white. Wild rice goes furthest of all by weight. Every one of those figures is a USDA mass balance, not a rule of thumb.
Should I rinse rice before cooking?
For anything you want to be separate and fluffy, yes: rinsing takes off loose surface starch that otherwise glues the grains. For risotto, absolutely not — that starch is the sauce. Parboiled rice does not need it. What rinsing does not do is change the water budget, unless you fail to drain it properly, in which case you have quietly added water you did not measure.
Does soaking rice change how much water to use?
Yes, by about a fifth of the dry weight of the rice, because that is roughly how much water the grain takes up in half an hour. For a US cup of rice that is about 37 g, or 0.16 cups, and you subtract it from the cooking water if you drained the rice. The bigger reason to soak has nothing to do with the arithmetic: it hydrates the grain evenly, so the outside does not gelatinise before the middle is wet. That is the commonest cause of rice that is somehow both soggy and undercooked.
Why does a rice cooker need less water than a saucepan?
Because almost nothing escapes from it. The entire difference between appliance ratios is the evaporation term. Bob’s Red Mill publish three ratios for one single product — 1¾ cups on the stovetop, 1¼ in a pressure cooker, 2 in a slow cooker — and the rice is identical in all three. Also: the cup that came with your cooker is almost certainly the Japanese go at 180 mL, not a US cup at 237, and using the wrong one is a 31% error before you start.
Is wild rice cooked like rice?
It is not rice. Wild rice is Zizania, a North American aquatic grass, and it behaves differently in every respect that matters here: it comes in at 7.9% moisture rather than 11.6%, it takes 45 minutes rather than 17, and it absorbs a great deal more water — USA Rice publish 3:1. It is on this page because people cook it and want a number, not because the botany allows it.
Related calculators
References
- USA Rice Federation. How to Cook Rice, usarice.com. The industry body’s own table of liquid ratios and times by variety: 2:1 for long-grain white, US jasmine and US basmati; 1.5:1 medium grain; 1.25:1 short grain; 2.25:1 brown, parboiled and parboiled brown; 3:1 wild rice; 4:1 arborio. Also the yield figures — one cup dry to three cups cooked, one cup dry about 7 oz.
- U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy. fdc.nal.usda.gov. A work of the United States Government and in the public domain. Every gram weight, water content and sugar profile on this page is a published FoodData Central value and the FDC id is given in the table beside it. Specifically: rice, white, long-grain, regular, raw (169756) and cooked (169757); rice, brown, long-grain, raw (169703) and cooked (169704); wild rice, raw (169726) and cooked (168897).
- America’s Test Kitchen. Nailing the Perfect Ratio of Water to Rice. Seventeen varieties cooked in vacuum-sealed bags to eliminate evaporation, with the finding that “1 cup of water should be sufficient to hydrate 1 cup of rice, regardless of type” and that “the water in excess of this 1:1 ratio is included to account for evaporation during cooking”. This page is essentially a quantitative version of that observation.
- Bob’s Red Mill. Basic Preparation Instructions for Wild Rice and Brown Rice. One product, three published ratios: 1¾ cups of water per cup on the stovetop, 1¼ cups in a multi-cooker at high pressure, 2 cups in a slow cooker. Used here as the direct evidence that the method, not the rice, moves the ratio.
- Cook’s Illustrated. Sushi Rice: 1 cup of sushi rice to 1¼ cups of water, rinsed until the water runs clear, 20 minutes covered and 10 minutes standing.
- Tilda. How to cook perfect basmati rice, tilda.com. Their absorption method is 120 g of rice to 240 g of water, which they describe as “a 2 to 1 water to rice ratio” — a ratio by MASS, and about 1.56:1 by volume once the bulk density of basmati is applied. The same page also equates 120 g with “1 cup”, which a cup of basmati is not. Cited as published, and as an illustration of why this page insists on saying whether a ratio is by weight or by volume.
- Bakalis S, Kyritsi A, Karathanos VT, Yanniotis S. Modeling of rice hydration using finite elements, and the water-uptake study in the CIGR Journal reporting brown rice moving from 0.132 to about 0.39 kg water per kg dry solids on soaking. The source of the 0.2 g per gram figure this page uses for a 30-minute soak.
- National Institute of Standards and Technology. NIST Handbook 44, Appendix C, General Tables of Units of Measurement. The US liquid gallon is 231 cubic inches exactly and the international inch is 25.4 mm exactly; every volume on this page descends from those two definitions.