Cooking Converter

Background.

This cooking conversions calculator translates between the three measurement systems that collide in every home kitchen: volume (cups, tablespoons, teaspoons, fluid ounces, milliliters, liters, pints, quarts, gallons), weight (grams, kilograms, ounces, pounds), and temperature (Celsius, Fahrenheit, Kelvin). It uses the conversion factors published by the National Institute of Standards and Technology in NIST Special Publication 811 (2008), the US legal-metrology reference for the international yard-and-pound agreement, the avoirdupois ounce, and US customary capacity units. A US cup is exactly 236.5882365 mL (NIST SP 811 Table B.6, derived from the US gallon defined as 231 cubic inches), a tablespoon is one half of a US fluid ounce or 14.7868 mL, a teaspoon is one third of a tablespoon or 4.92892 mL, an avoirdupois pound is exactly 453.59237 g (NIST SP 811 Table B.8, fixed by the 1959 international agreement), and the Fahrenheit-to-Celsius conversion is the affine map C = (F − 32) × 5⁄9 anchored at the freezing point of water. The calculator computes every result using decimal.js arbitrary-precision arithmetic so that 1 cup ÷ 16 returns exactly 14.7868 mL per tablespoon rather than a 14.78679999… approximation, and 350 °F returns exactly 176.666… °C — the value oven dials actually need rather than the rounded 175 °C that propagates through internet recipe sites.

The reason a dedicated cooking conversions calculator exists, separate from a general-purpose unit converter, is that cooking is the one domain where the unit choice is doing more work than the arithmetic. The US cup is not the same as the metric cup (250 mL, used in Australia and New Zealand) or the legacy UK cup (about 284 mL, deprecated since the 1980s but still printed in older British cookbooks); the US tablespoon is 14.7868 mL but the Australian tablespoon is exactly 20 mL by national standard, which means an Australian recipe specifying '2 tablespoons of soy sauce' is asking for 40 mL and a US cook reading it as US tablespoons will under-pour by 25 percent. Volume measurement is fine for liquids, where density is well-defined and a fluid ounce of water is a fluid ounce of water regardless of who measured it, but it fails for dry ingredients, where the same nominal cup can hold 30 percent more or less ingredient depending on whether you scooped or spooned, whether you tapped the cup, whether the flour was sifted, and whether the air was humid.

The King Arthur Baking Company's published Ingredient Weight Chart — the closest thing American home baking has to a definitive reference — gives 1 cup of all-purpose flour as 120 g, 1 cup of bread flour as 120 g, 1 cup of cake flour as 116 g, 1 cup of whole wheat flour as 113 g, and 1 cup of granulated sugar as 198 g, which is to say five different weights for five different ingredients in the same nominal volume. Professional pastry kitchens, every recipe America's Test Kitchen and Cook's Illustrated have published in their baker's-percentage workflow, and the entire Modernist Cuisine library work in grams for exactly this reason: gram-weights are reproducible, scale-independent, and remove every ambiguity that makes home baking inconsistent.

The calculator also handles oven temperature, where the failure mode is different but just as common — a US recipe specifying 350 °F (the workhorse moderate-oven temperature) translates to 176.67 °C, which is between the 175 °C mark and the 180 °C mark on a European oven dial; most cooks round to 180 °C and accept the 1.6 percent overshoot, but for delicate work (custards, choux pastry, soufflés) the round-down to 175 °C is safer. Gas-mark ovens add another layer: gas mark 4 is the equivalent of 350 °F / 177 °C, gas mark 6 is 400 °F / 204 °C, and the conversion is a discrete lookup table rather than a continuous formula.

Below the widget you will find a section on how volume, weight, and temperature differ mathematically as conversion problems, the NIST SP 811 factor table the calculator uses, a worked example walking through the 1 cup → 16 tbsp → 48 tsp identity and the 350 °F → 176.67 °C oven conversion, and FAQs covering the questions that actually arise in a real kitchen — US vs UK cup, why dry-vs-liquid measure matters, why baking by weight is the professional standard, why 1 cup of flour does not have a single weight, and how to read a gas-mark dial.

What is cooking converter?

Cooking conversion is the translation of a recipe's measurement from one unit system to another while preserving the cook's intent. Three sub-problems live under that umbrella and each has different math. Volume conversion is purely multiplicative: every volume unit is a fixed multiple of a canonical base (the calculator uses the milliliter), and converting from one to another is one multiplication and one division. The NIST SP 811 factor table gives the exact values: 1 tsp = 4.92892 mL, 1 tbsp = 14.7868 mL, 1 cup = 236.588 mL, 1 fl oz = 29.5735 mL, 1 pint = 473.176 mL, 1 quart = 946.353 mL, 1 gallon = 3785.41 mL. The relationships are also internally consistent — 1 tbsp = 3 tsp exactly, 1 cup = 16 tbsp = 48 tsp exactly, 1 cup = 8 fl oz exactly, 1 pint = 2 cups, 1 quart = 2 pints, 1 gallon = 4 quarts — and the calculator's factor table reproduces all of these identities to the full precision of decimal.js. Weight conversion is the same shape of problem, just with grams as the base: 1 oz = 28.3495 g (NIST SP 811 Table B.8 avoirdupois ounce), 1 lb = 453.592 g (the international avoirdupois pound), 1 kg = 1000 g. Volume and weight are not interconvertible without an ingredient density — 1 cup of water weighs 236.6 g (water is 1 g/mL by definition), but 1 cup of all-purpose flour weighs about 120 g (flour is roughly 0.5 g/mL when scooped, per King Arthur), 1 cup of granulated sugar weighs 198 g, and 1 cup of honey weighs about 340 g. The calculator deliberately does not attempt cross-category conversions (cup → gram) because the answer depends on what is in the cup, and a calculator that silently used a single density (water's, usually) would mislead more often than it would help. Temperature conversion is the third sub-problem and is the only one that is affine rather than linear: the Celsius and Fahrenheit scales have different zero points and different unit-of-scale, so the conversion requires both a multiplicative factor (5⁄9 or 9⁄5) and an additive offset (32 °F). The calculator handles temperature by routing every conversion through °C using F = (C × 9⁄5) + 32 and K = C + 273.15. Negative values are legal for temperature (your freezer is −18 °C) but rejected for volume and weight, which are strictly positive magnitudes.

How to use this calculator.

1. 01Pick the category that matches what you are converting — Volume for liquid and bulk-volume measurements (cups, tbsp, tsp, mL, fl oz, pints, quarts, gallons), Weight for mass measurements (grams, kilograms, ounces, pounds), or Temperature for oven settings (°C, °F, K). The calculator uses three completely separate factor tables and the category choice tells it which one to apply.
2. 02Type the value you want to convert. For volume and weight this must be a positive number — a recipe never asks for −2 cups of flour. For temperature any real number is legal: −18 °C is the standard home-freezer setting, 0 °C is the freezing point of water, 100 °C is its boiling point, 350 °F is a moderate American oven, 220 °C is a hot European oven.
3. 03Pick the From unit from the dropdown. The list includes every supported unit across all three categories, but the calculator validates that the unit belongs to the category you picked — choosing Volume and then 'gram' as the from-unit will raise a clear error rather than silently treat the gram as if it were a milliliter.
4. 04Pick the To unit. Same dropdown, same validation rule. The most common conversions are cup → mL, tbsp → mL, tsp → mL, °F → °C, oz → g, and lb → kg, in that rough order of frequency for American home cooks reading European or professional recipes.
5. 05Read the Converted value — the headline result, in the target unit, rendered at the precision the context needs. The two secondary fields show the value in the canonical base unit (mL for volume, grams for weight) so you can cross-check; they read 0 for temperature, where there is no canonical mL or gram equivalent.
6. 06For baking work where reproducibility matters, convert volume measurements to grams once at the start of the recipe and work in grams from there. King Arthur's Ingredient Weight Chart gives exact gram-equivalents for every common baking ingredient at the kind of precision (120 g per cup of all-purpose flour, 198 g per cup of granulated sugar) that this calculator's symmetric volume → mL → user-supplied-density → gram workflow cannot match in one shot.

The formula.

The calculator runs three distinct conversion paths, one per category.

Volume — base unit mL. Every volume unit is stored as its size in milliliters and the conversion is one multiplication and one division: result = value × fromFactor ÷ toFactor. The NIST SP 811 (2008) Table B.6 factors are:

1 tsp = 4.92892 mL (1⁄3 of a tablespoon) 1 tbsp = 14.7868 mL (1⁄2 of a US fluid ounce) 1 fl oz = 29.5735 mL (1⁄128 of a US gallon) 1 cup = 236.588 mL (8 fl oz) 1 pint = 473.176 mL (2 cups) 1 quart = 946.353 mL (2 pints) 1 gallon = 3785.41 mL (4 quarts, defined as 231 in³) 1 mL = 1 mL 1 L = 1000 mL

The identity 1 cup = 16 tbsp = 48 tsp is reproduced exactly by these factors: 236.588 ÷ 14.7868 = 16.0000…, 236.588 ÷ 4.92892 = 48.0000….

Weight — base unit gram. NIST SP 811 (2008) Table B.8 (avoirdupois):

1 g = 1 g 1 kg = 1000 g 1 oz = 28.3495 g (avoirdupois ounce) 1 lb = 453.592 g (international avoirdupois pound, exactly 0.45359237 kg by 1959 international agreement, NIST SP 811)

Same formula: result = value × fromFactor ÷ toFactor. 1 lb ÷ 1 oz = 453.592 ÷ 28.3495 = 16.000…, the expected 16 oz per lb.

Temperature — affine, anchored on °C. The Celsius and Fahrenheit scales have different zero points and different scale factors, so the conversion requires both a multiplication and an offset. The calculator implements two helper functions:

toCelsius(value, unit): C → C: value F → C: (value − 32) × 5⁄9 K → C: value − 273.15

fromCelsius(C, unit): C → C: C C → F: C × 9⁄5 + 32 C → K: C + 273.15

A generic temperature conversion is therefore toCelsius(value, fromUnit) followed by fromCelsius(°C, toUnit). Two examples baked into the engine's test suite: 350 °F → (350 − 32) × 5⁄9 = 318 × 5⁄9 = 176.66… °C; 100 °C → 100 × 9⁄5 + 32 = 180 + 32 = 212 °F (the boiling point of water at sea-level standard pressure). The Kelvin offset 273.15 is exact by the 2019 SI redefinition that fixed the kelvin via the Boltzmann constant; the Celsius-to-Fahrenheit 5⁄9 ratio and the 32 offset are exact by international agreement and have been the published conversion since the formal adoption of the international temperature scales.

The entire calculation runs at twenty significant digits in decimal.js so that the published-to-six-decimal-places NIST factors (4.92892 mL per tsp, etc.) round-trip exactly and do not drift in the eighth decimal place the way they would in raw JavaScript double-precision floats.

A worked example.

Frequently asked questions.

References& sources.

1. [1]National Institute of Standards and Technology. NIST Special Publication 811 (2008 edition) — Guide for the Use of the International System of Units (SI). Authoritative source for the US customary volume factors in Table B.6 (cup = 236.5882365 mL, tablespoon = 14.78676478125 mL, teaspoon = 4.92892159375 mL, US gallon = 3.785411784 L) and the avoirdupois mass factors in Table B.8 (pound = 453.59237 g, ounce = 28.349523125 g) used throughout this calculator.
2. [2]King Arthur Baking Company. Ingredient Weight Chart. The closest thing American home baking has to a definitive reference, listing tested gram-equivalents for cup-volumes of every common baking ingredient under the spoon-and-level filling convention: 120 g per cup all-purpose flour, 198 g granulated sugar, 213 g brown sugar (packed), 227 g butter (1 stick = 113 g = 1⁄2 cup), 340 g honey. The source the calculator's FAQs and intro cite for the variable density of flour by type.
3. [3]United States Department of Agriculture, Agricultural Research Service. FoodData Central. The federal nutrient database, which publishes density-equivalent gram weights for every food in its catalogue (typical cup-of-X mass values, used as the regulatory reference for nutrition-label serving-size calculations). The independent cross-check to King Arthur for cup-to-gram density of common baking ingredients.
4. [4]America's Test Kitchen / Cook's Illustrated. The Cook's Illustrated Baking Book and The Science of Good Cooking (Cook's Illustrated editors, 2012). The published reference for the modern American baking method, including the spoon-and-level technique, the cup-vs-weight reproducibility argument, and the published gram-equivalents per ingredient used throughout the ATK recipe corpus. The editorial home of the 'weigh, do not measure' rule for serious baking.
5. [5]Myhrvold, Nathan; Young, Chris; Bilet, Maxime. Modernist Cuisine: The Art and Science of Cooking, Volume 2 — Techniques and Equipment. The Cooking Lab, 2011. Chapter on measurement standards: rationale for measuring all dry ingredients by mass in grams, discussion of the cup-volume reproducibility problem, and the workflow used by every professional pastry kitchen and most of the modernist restaurant world.
6. [6]Bureau International des Poids et Mesures (BIPM). The International System of Units (SI Brochure), 9th edition (2019). Treaty-level reference for the kelvin redefinition (fixing it via the Boltzmann constant) that underpins the Celsius-Kelvin offset of exactly 273.15 used in the calculator's temperature path.