Cup Sizes Around the World: US, Metric, Imperial, Australian & Japanese Cups

A “cup” is not one fixed volume. A US cup holds 236.588 milliliters (ml), a metric cup used in Australia, New Zealand, Canada, and South Africa holds 250 ml, an old British imperial cup holds about 284 ml, and a Japanese cup holds 200 ml. That is a spread of 84 ml between the smallest and largest, about a 42% difference, all called by the same word. Pick the wrong one and a “cup of flour” can be off by 20% or more before you have accounted for how tightly the flour was packed.

This guide compares the cup standards you are likely to meet in a recipe, shows how to tell which one a recipe is using, and works through the numbers so the difference stops being abstract. For the mechanics of turning any gram amount into cups, see the grams to cups formula guide; this article is about the cup itself, not the conversion method.

The US Cup: Customary and Legal

Nearly every US measuring cup, and every grams-per-cup figure on this site, is built on the US customary cup: 8 US fluid ounces, or 236.588 ml. It is the cup home cooks mean when a recipe simply says “cup” without qualification.

A second, slightly larger figure shows up on nutrition labels: the US legal cup, fixed at exactly 240 ml. The US Food and Drug Administration’s guidance on household measures for nutrition labeling states that “1 cup means 240 mL” for the purpose of listing serving sizes. The National Institute of Standards and Technology’s Metric Kitchen reference uses the same rounded 240 mL figure for everyday US kitchen conversions.

The gap between the two US cups is small: 240 - 236.588 = 3.412 ml, about 1.4%. Over 3 cups of milk that is 3 x 3.412 = 10.236 ml, close to 2 teaspoons (10.236 ÷ 4.929 = 2.08 tsp using the precise 4.929 ml teaspoon). It is not zero, but it is small enough that no home recipe distinguishes between the two in practice. The distinction mostly matters when you are checking a nutrition label’s math against a recipe’s own cup measurements, not when you are baking.

The Metric Cup: 250 ml in Australia, New Zealand, Canada, and South Africa

Countries that measure cooking by the metric system generally settled on a clean, rounded 250 ml cup rather than converting the US cup exactly. Australia, New Zealand, Canada, and South Africa all use this figure. It is 250 - 236.588 = 13.412 ml larger than a US cup, about 5.7% more volume in the same “1 cup.”

Australia’s cup and its unusual tablespoon

Australia’s cup and spoon sizes are set out in Standards Australia’s AS 1325 specification for measuring cups and spoons, and the Australian Government’s overview of the national measurement system describes how Australia’s legal units of measurement are established and maintained. The Australian cup follows the standard 250 ml metric cup, but the tablespoon does not follow the usual metric pattern: it is 20 ml (4 teaspoons) rather than the 15 ml (3 teaspoons) used almost everywhere else that has metricated, including the US, UK, and New Zealand.

That makes Australia the outlier twice over: its cup matches the rest of the metric world, but its tablespoon does not. A recipe that gives both cups and tablespoons in Australian units needs each unit converted separately; you cannot assume the tablespoon scales the same way the cup does.

New Zealand’s cup

New Zealand also uses the 250 ml metric cup, but its tablespoon follows the more common 15 ml standard, the same size used in the US and UK. So an Australian recipe and a New Zealand recipe can share an identical cup measurement while disagreeing on what “1 tablespoon” means: 20 ml across the Tasman Sea in Australia, 15 ml in New Zealand. This is a common source of confusion, since Australian and New Zealand recipes are often assumed to be interchangeable. For the full breakdown of that 20 ml spoon and how it changes small-ingredient amounts, see US vs Australian tablespoon.

The Historic Imperial Cup (About 284 ml)

Before Britain adopted metric cooking measures, a “cup” in British usage was defined as half an imperial pint. The imperial pint itself comes from the imperial gallon, fixed under the UK’s Weights and Measures Act 1985 at exactly 4.54609 liters. Working through the definition: one imperial pint is 4.54609 ÷ 8 = 0.56826125 liters, or 568.26125 ml, and half of that, the old imperial cup, is 568.26125 ÷ 2 = 284.130625 ml, rounded in practice to about 284 ml.

That is important to state carefully, because it is easy to misdescribe. This is the historic imperial cup, not a current UK standard. Modern UK recipes are almost never written in cups at all; British, Irish, and most Commonwealth cookbooks state ingredient amounts in grams by weight and milliliters by volume, following metric convention, with teaspoons and tablespoons (both 5 ml and 15 ml respectively) as the main small-volume units. A roughly 284 ml cup mainly turns up in older sources: handwritten family recipe cards, cookbooks printed before the 1970s metric transition, or recipes reprinted from that era without being updated. If you are working from a grandmother’s handwritten recipe card written in imperial Britain, checking whether “1 cup” means 284 ml or a US-style 236.588 ml is worth doing before you convert anything else.

The Japanese Cup (200 ml) and the Separate Rice Cup

A standard Japanese cup, the size marked on measuring cups sold in Japanese kitchenware shops, is 200 ml, about 15% smaller than a US cup (236.588 - 200 = 36.588 ml difference, or 36.588 ÷ 236.588 = 15.5%). This is the cup a Japanese recipe means when it calls for “1 kappu” (1カップ) of an ingredient.

Rice, however, uses a different unit entirely. Japanese rice cookers are calibrated to a traditional volume called a go, roughly 180 ml, which predates the modern 200 ml cup and is still the unit printed on the plastic cup that comes with a rice cooker. A go of raw, uncooked rice weighs about 150 g. If you measured rice with a 200 ml cup instead of the 180 ml rice cup that came with the cooker, you would add 200 - 180 = 20 ml more rice than the cooker’s water-to-rice ratio expects, about 11% too much, which is enough to throw off the texture of the cooked rice. When a recipe calls for a “cup” of rice specifically for a rice cooker, that cup is very likely the 180 ml go, not the 200 ml general Japanese cup.

How to Tell Which Cup Standard a Recipe Uses

Most recipes never state which cup they mean. A handful of context clues narrow it down quickly:

• Oven temperature units. Fahrenheit (350°F) points to a US recipe. Celsius (180°C) or a gas mark (Gas Mark 4) points to the UK, Australia, New Zealand, or another metric country.
• Spelling. “Colour,” “flavour,” “litre,” and “programme” indicate British-influenced spelling, common to the UK, Australia, New Zealand, and South Africa. “Color,” “flavor,” and “liter” indicate American spelling.
• Ingredient names. “Plain flour,” “self-raising flour,” “caster sugar,” “icing sugar,” and “cornflour” are British, Australian, and New Zealand terms. “All-purpose flour,” “granulated sugar,” “powdered sugar,” and “cornstarch” are American. “Bicarbonate of soda” versus “baking soda” is the same split.
• Butter in sticks. US recipes often measure butter in sticks (1 stick = 113.5 g = 8 tbsp = ½ cup). Butter sold in Australia, the UK, and most of Europe comes in blocks, usually 250 g, so a recipe that references “one stick” is almost always American.
• Rice and rice cooker instructions. A recipe that pairs “1 cup rice” with a rice cooker and a specific water line is very likely using Japan’s 180 ml go, not a 200 ml or 236.588 ml cup.
• A recipe that gives only grams and milliliters, no cups at all. This is typical of contemporary UK, European, and professional-kitchen recipes, and it is also the format that removes the cup-standard question entirely.

None of these clues is airtight on its own. A recipe with American spelling but no oven temperature, for instance, still leaves some doubt. Two or three clues together are usually enough to make a confident call.

Cup Standards Compared: A Reference Table

Reading the table by volume alone: the historic imperial cup is the largest at 284 ml, and the rice cooker’s go is the smallest at 180 ml, a difference of 284 - 180 = 104 ml, close to 44% of the smaller value. Most cups you will actually meet in a modern recipe fall in the narrower band between 200 ml and 250 ml.

How Cup-Size Differences Show Up in Your Bowl

A bigger cup does not just hold “a bit more.” Because grams measure mass and a cup measures volume, the extra volume multiplies by the ingredient’s own density every time, so the gram difference compounds across every ingredient in a recipe, not just one. The table below scales three common ingredients, all measured level with no packing, across the main cup standards:

Two patterns stand out. First, the gap between cup standards grows with the ingredient’s density: water tracks the milliliter figure almost exactly (density near 1 g/ml), while flour and sugar diverge from it because they are lighter or denser than water. Second, the absolute gram gap for flour and sugar is smaller than for water in this table only because flour and sugar are less dense than water; in relative, percentage terms, every ingredient shifts by the same amount, since the volume ratio between cups does not change by ingredient. A more detailed breakdown of how flour density varies covers the reasons dry ingredients are harder to pin down than liquids even within a single cup standard.

The practical result: swap a metric-cup recipe’s flour into a US measuring cup, cup for cup, and you lose about 127 - 120 = 7 g per cup, or roughly 5.5%. Over a 4-cup batch of flour that reaches 4 x 7 = 28 g short, close to ¼ cup of flour missing from the bowl, entirely from the cup-size mismatch and before any difference in how firmly the flour was packed.

Five Worked Conversions Between Cup Standards

Each example below shows the full calculation, not just the answer.

An Australian recipe calls for 2 cups of plain (all-purpose) flour. Using Australia’s 250 ml metric cup, 2 cups = 500 ml. All-purpose flour weighs 120 g per 236.588 ml US cup, a density of 120 ÷ 236.588 = 0.5072 g/ml. So 500 ml of flour weighs 500 x 0.5072 = 253.6 g, which rounds to 254 g. Scoop that same “2 cups” with a US measuring cup instead and you get 2 x 120 = 240 g, a shortfall of 254 - 240 = 14 g, close to 2 tablespoons of flour (14 ÷ 7.5 g per tbsp = 1.87 tbsp) missing from the recipe.

A Japanese recipe calls for 1 cup of granulated sugar, using Japan’s 200 ml cup. Sugar weighs 200 g per 236.588 ml US cup, a density of 200 ÷ 236.588 = 0.8453 g/ml. So 200 ml of sugar weighs 200 x 0.8453 = 169.1 g, which rounds to 169 g. Measure the same “1 cup” with a US cup instead and you get 200 g, about 200 - 169 = 31 g, or 31 ÷ 169 = 18.3% more sugar than the Japanese recipe intended.

A nutrition label lists “1 cup milk (240 mL),” the US legal cup, but your measuring cup is a standard US customary cup at 236.588 ml. The gap per cup is 240 - 236.588 = 3.412 ml. Over 3 cups that is 3 x 3.412 = 10.24 ml, about 2 teaspoons (10.24 ÷ 4.929 = 2.08 tsp). This is the smallest gap of any pair of cup standards here, small enough to disregard for baking, though not literally zero.

An old handwritten British recipe calls for “1 cup of flour,” using the historic imperial cup of 284.13 ml (half of the 568.26125 ml imperial pint, itself an eighth of the 4.54609 L imperial gallon). At all-purpose flour’s density of 0.5072 g/ml, that cup holds 284.13 x 0.5072 = 144.1 g, which rounds to 144 g. A US cup of the same flour is 120 g, so the old imperial cup carries 144 - 120 = 24 g more, about 24 ÷ 120 = 20% more flour for the same “1 cup” instruction.

An Australian recipe calls for 2 tablespoons of cocoa powder, using Australia’s 20 ml tablespoon. That is 2 x 20 = 40 ml of cocoa. A US tablespoon holds 14.787 ml (NIST rounds this to 15 ml for everyday use), so matching that volume takes 40 ÷ 14.787 = 2.71 US tablespoons, not 2. Measuring 2 level US tablespoons instead gives you 2 x 14.787 = 29.57 ml, a shortfall of 40 - 29.57 = 10.43 ml, about 26% less cocoa than the Australian recipe intended, purely from the tablespoon mismatch, with the cup standard not even involved.

When Grams Are Safer Than Any Cup Conversion

Every example above has two independent sources of error stacked on top of each other: which cup standard the recipe used, and how densely an ingredient was packed into that cup. A cup conversion only fixes the first problem, and only if you correctly identify which standard the recipe meant.

Weighing removes both problems at once. 240 g of flour is 240 g of flour whether the recipe was written in New York, Sydney, or Osaka, and whether the cook who wrote it packed the flour firmly or spooned it in lightly. That is why the Metric Kitchen guidance from NIST treats measuring by mass as a more reliable practice than measuring by volume, independent of which country’s kitchen you are standing in.

Grams matter most when:

• The recipe’s origin is unclear or mixed. A recipe collected from a forum, a translated site, or a family archive may mix US, metric, and even historic imperial habits in the same document. A scale sidesteps the guesswork.
• You are scaling a recipe up or down. Doubling 2⅓ cups by eye invites rounding error at every ingredient; doubling 280 g is exact. The recipe scaler keeps gram quantities consistent when you resize a recipe.
• The bake is structural. Bread, laminated dough, and cake batters depend on ratios between flour, liquid, and fat; a 5 to 20% cup-standard mismatch changes those ratios enough to affect texture and rise.
• You only have one measuring cup and the recipe was written elsewhere. Rather than guess whether to add or subtract a correction factor, weigh the ingredient using its known grams-per-cup value and skip the cup-standard question. The ingredient database lists that value for common baking staples, and the cups to grams converter runs the math for a specific amount.

Cups remain perfectly workable when you know which standard the recipe uses and the ingredient is forgiving of small shifts (pancakes, soups, casual baking). The risk is not cups themselves; it is converting between two different cups without realizing it.

Quick Reference

• US customary cup: 236.588 ml, the basis for US recipes and this site’s ingredient data.
• US legal cup: 240 ml, used on FDA nutrition labels.
• Metric cup: 250 ml, used in Australia, New Zealand, Canada, and South Africa.
• Historic imperial cup: about 284 ml, found in older British and Commonwealth recipes, not modern UK cooking.
• Japanese cup: 200 ml, for general Japanese recipes.
• Japanese rice cup (go): about 180 ml, specific to rice cookers and uncooked rice.
• When the standard is uncertain, weigh the ingredient instead. The grams to cups converter handles the arithmetic once you know the grams-per-cup figure for your ingredient.