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Ratio {{ resultsReady ? `1 : ${formatNumber(computation.values.ratio)}` : '—' }} Portions {{ resultsReady ? formatNumber(computation.values.planning.servings) : '—' }}
Volume of uncooked rice; 30–3,000 mL. Check the pot or cooker capacity.
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Use 0 to keep the preset, or enter 0.5–4 volumes of water per volume of dry rice.
× rice
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Use a measured adjustment for your pot or preferred texture. Zero leaves the ratio unchanged.
%
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Planning assumption: cooked volume divided by dry volume. Actual yield varies.
× dry
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Choose the amount of cooked rice you plan to serve per person.
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Optional: 0 hides the comparison. A target does not change your current batch.
portions
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Measure this batch

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Prepare and cook

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Use the right ratio

Rice : water = 1 : {{ formatNumber(computation.values.ratio) }} by volume. {{ computation.values.ratio_note }}

Cooked yield is an editable estimate of {{ formatNumber(computation.normalizedInputs.yield_factor.value) }} times dry volume, not dry rice plus water.

Reference: Lundberg {{ computation.values.rice_label }} instructions, checked 9 September 2026. Instant rice, risotto, pressure cooking and steamed sticky rice need their own instructions.

The chart renderer is unavailable. The measurement ledger still contains all volumes.

Measurement Value Unit Basis Copy
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The cup supplied with a rice cooker is often smaller than a kitchen measuring cup. Measuring rice with one and water with the other changes the rice-to-water ratio, even when both amounts are described as cups. A known cup size makes the difference between repeating a recipe and unintentionally changing it.

Cup Volume in mL
Rice-cooker cup, common nominal size 180
US measuring cup About 236.59
Metric measuring cup 250

A rice-to-water ratio compares dry, uncooked rice with the water added for cooking, using the same volume unit for both. One measure of rice and one and a half measures of water form the same ratio whether both are measured with a small cup or a large one, although the batch size changes. This is not a ratio by weight, and discarded rinse or soak water is not part of the measured cooking water.

In covered-pot absorption cooking, the grains take up water while some escapes as steam. Water quantity, heat and keeping the lid on all affect the result. Hard centers can mean that more liquid or cooking is needed, while too much water can contribute to rice that is softer than intended. Cooking rice in excess water and draining it afterwards follows a different method.

Rice type and preparation matter as well. Brown rice generally takes longer to cook than white rice. Sushi rice is intended to cling together, while long-grain rice is often chosen for dishes with separate grains. Rinsing and soaking are different operations, so a drained soak needs instructions that account for that preparation. Measuring the rice before either treatment keeps the starting quantity clear.

For dinner or meal preparation, cooked yield is the volume expected after cooking, and portion size is the cooked volume planned for each serving. A larger bowl uses that yield faster than a small accompaniment, so a dry cup is not a fixed number of meals. Nor is finished rice volume simply dry rice volume plus added water. Package instructions for the exact batch, along with an appliance’s own measuring cup, water lines and capacity limits, take priority over a general ratio. Increasing a batch does not necessarily increase cooking time or evaporation in the same proportion.

How to Use This Tool:

Start with the dry rice measurement taken before rinsing or soaking. Results update as you change the entries.

  1. Choose the unit beside Dry rice, then enter your measured amount. Switching units later converts the existing volume rather than keeping the same cup count.
  2. Select Rice type, Cooking method and Preparation to match your batch. For a rice cooker, follow the appliance’s program and water marks rather than expecting a stovetop time estimate.
  3. Open Advanced when your package specifies a different ratio. Leave Package water ratio at 0 to retain the preset, or enter the water volumes required per volume of dry rice. Use Water adjustment only for an additional change established for your pot or preferred texture.
  4. Set Cooked yield estimate and Cooked portion size when planning servings. Choose the portion unit before entering its amount; it can differ from the dry-rice unit. Enter Target portions to compare a different batch size, or leave it at 0 to hide that comparison.
  5. Read Water to add in the selected dry-rice unit and check the Cooking guide against your package. The Measurement ledger supplies the same water amount in mL and the three cup sizes.
    If Check the rice inputs replaces the water estimate, correct the highlighted input. The water result remains unavailable until the dry-rice, ratio and other required cooking inputs are valid.

Interpreting Results:

Water to add means fresh cooking water, excluding discarded rinse or soak water. The Ratio reads rice first and water second. Presets scale Lundberg’s one-cup product instructions; they are not universal ratios for every brand, a live package lookup or calibrated cooker fill lines. Compare the estimate with the instructions for the rice and batch you are actually cooking.

Estimated cooked yield and Estimated portions depend on your chosen yield factor and cooked portion size. A fractional portion count is an estimate of volume available, not a count rounded up to whole people or a dietary recommendation. The Volume comparison shows separate amounts in mL, not three quantities to add together for pot capacity.

Plan another batch provides separate dry-rice and water quantities for the target. It does not replace the current Dry rice entry or change the main water result. Check that proposed batch against package batch instructions and vessel capacity; no automatic capacity check or division into smaller batches is performed.

Entering a custom ratio does not add cooking guidance for instant rice, risotto, pressure cooking or steamed sticky rice. Those preparations need their own instructions. Sushi rice here follows a measured-water cooking method, not glutinous-rice steaming.

Technical Details:

Added water is estimated by proportional volume scaling. A base water-to-rice ratio receives any chosen percentage adjustment, then multiplies the dry rice volume. Evaporation, retained rinse water and water already absorbed during soaking are not calculated separately. Cooked yield and portions are declared planning assumptions rather than calibrated product measurements.

Water volume and ratio adjustments

Let D be dry rice volume in mL, r0 the base ratio, a the entered Water adjustment percentage, r the adjusted ratio and W the water to add in mL. The percentage changes the whole base ratio rather than adding a fixed volume of water.

r=r0× (1+a100) W=D×r

A Package water ratio of 0 selects the rice reference below. A value from 0.5 to 4 replaces that reference. The adjustment is applied afterwards, so the permitted combinations can produce adjusted ratios from 0.425 to 4.6. There is no second restriction forcing the adjusted ratio back into the package-ratio range.

Volume conversion

For an entered dry-rice quantity q, k is the number of mL in its selected unit. Multiplication gives dry rice in mL; division expresses the calculated water in that same selected unit.

D=q×k Wselected=Wk

The conversion factors are 1 for mL, 250 for a metric cup, 236.5882365 for a US cup and 180 for the nominal cooker cup. The full US-cup factor is used despite the rounded 236.59 mL label. Cooked portion measurements use these same factors independently of the dry-rice unit. No rice weight-to-volume conversion is performed.

Cooked yield and portions

Cooked volume C uses the editable Cooked yield estimate y. Dividing C by the chosen Cooked portion size P, expressed in mL, gives the estimated portion count N.

C=D×y N=CP

The initial yield factor is 3 and the initial cooked portion is 150 mL. The same starting yield factor applies to all six rice choices; it is an editable planning assumption, not a measured yield for each product. Changing rice type, preparation, cooking method or water ratio does not automatically change that factor. Water volume is not used in the cooked-yield equation.

For a positive Target portions value T, the required cooked volume is divided by the yield factor to obtain target dry rice DT. Target water WT uses the same adjusted ratio r.

DT=T×Py WT=DT×r

The 30 to 3,000 mL dry-rice limit applies to the entered current batch, not to calculated target quantities. A target can therefore propose more or less dry rice than that entry range. Target amounts are not capped or rounded to a vessel size.

Manufacturer-specific ratios and times

These base ratios and reference simmer times come from Lundberg’s one-cup product instructions. The ratio column gives volumes of water per volume of dry rice. Times describe the covered stovetop method, subject to the preparation rules below.

Rice type Base ratio Simmer in minutes
White long-grain 1.75 15
White jasmine 1.75 15
White basmati 1.75 15
Brown long-grain 2 45
Brown short-grain 2 45
Sushi / short-grain white 1.5 20

Linear scaling does not reproduce every package batch table. Both brown-rice references specify 2 cups of water for 1 cup of dry rice, but 3.5 cups of water for 2 cups of rice. The latter uses 1.75 water volumes per rice volume, not 2. The preset continues to scale the one-cup ratio rather than switching to the larger-batch instructions. A package ratio override can represent the ratio for the actual batch.

Preparation and timing rules

Standard stovetop simmering begins after the rice and measured water reach a boil. The guide then specifies a tight lid, gentle simmering and a covered 10-minute rest off the heat. Heating to boiling takes additional time. Neither batch size nor a custom ratio or water adjustment recalculates the reference simmer or rest duration.

For non-sushi rice, Prepare as directed on package and Already rinsed and drained retain the reference stovetop times. Already soaked and drained omits both the standard simmer and rest durations and directs you to soaked-rice instructions. No preparation choice automatically reduces the water ratio or subtracts retained water.

Sushi preparation calls for rinsing, a 30-minute soak, discarding the soak water and adding fresh measured cooking water. Choosing package preparation or already-rinsed rice still includes that soak. Choosing already-soaked rice assumes the rinse, 30-minute soak and draining are complete, so no additional soak is listed. The sushi stovetop guidance retains its 20-minute simmer and 10-minute rest.

Rice-cooker mode retains the same water calculation but supplies no numerical simmer or rest duration. It defers the cycle, rest, capacity and fill marks to the appliance. The sushi preparation note still applies when sushi rice is selected, subject to the appliance’s instructions. An omitted time is not a claim that cooking or resting takes zero minutes.

Accepted ranges and unavailable estimates

Range endpoints are inclusive. Errors in the water-related inputs prevent a usable cooking result, while errors in optional planning entries remove only the estimates that depend on them.

Input Accepted values Effect of an invalid entry
Dry rice Volume equivalent to 30 to 3,000 mL Water result and cooking guide unavailable
Rice type, cooking method, preparation and dry-rice unit One of the offered choices Water result and cooking guide unavailable
Package water ratio 0 for the preset, or 0.5 to 4 Water result and cooking guide unavailable
Water adjustment −15% to +15% Water result and cooking guide unavailable
Cooked yield estimate 1 to 5 times dry volume Cooked yield, portions and target quantities omitted; water and cooking instructions retained
Cooked portion size and its unit Volume equivalent to 50 to 500 mL in a supported unit Portions and target quantities omitted; valid cooked yield, water and cooking instructions retained
Target portions 0 to 30; 0 hides the comparison Target comparison omitted; current-batch quantities retained

Blank, nonnumeric or out-of-range entries are not silently replaced with sample values. Correcting an optional entry restores its estimates when the other required planning entries are also valid. Fractional target counts within the accepted range are calculated without rounding them to whole portions. The dry-rice endpoints allow 0.000000001 mL of conversion noise to avoid rejecting an equivalent boundary measurement after a unit conversion.

Precision and practical accuracy

Calculations retain unrounded numeric values. Displayed volumes, ratios and portion counts use at most two decimal places, without rounding batches up to whole cups or portions. For example, an adjusted ratio of 0.425 displays as 0.43, but water is calculated with 0.425. Extra decimal places do not account for differences in rice, draining, pot geometry, lid fit, heat or appliance operation. These accepted ranges are calculation limits, not recommended cooking quantities or evidence that a batch fits a particular vessel.

Worked Examples:

The starting batch in mL or metric cups

The initial setup uses 250 mL of dry white long-grain rice, stovetop cooking, package preparation and no ratio override or water adjustment. Multiplying 250 mL by 1.75 gives Water to add of 437.5 mL. The starting yield factor of 3 gives 750 mL of estimated cooked rice, or 5 portions of 150 mL. Changing the dry-rice unit to metric cups converts the rice entry to 1 and the water result to 1.75 metric cups. The physical batch and portion estimate stay the same.

An adjusted package ratio and a four-portion target

For 250 mL of dry rice, a package ratio of 2 with a −10% water adjustment produces an adjusted ratio of 1.8 and 450 mL of water. A chosen yield factor of 2.5 gives 625 mL cooked, which is 3.125 portions of 200 mL, displayed as 3.13. Setting Target portions to 4 proposes a separate batch. Four portions require 800 mL cooked, so dividing by 2.5 gives 320 mL dry rice; applying the 1.8 ratio gives 576 mL water. The current water result remains 450 mL until the dry-rice entry is changed. The target does not establish that this ratio or yield will suit an untested rice or pot.

References: