Cooking Measurement Converter
Convert cups, tablespoons and teaspoons between the US, metric, Australian, Japanese and imperial systems — where the same word means a different volume and an Australian tablespoon is four teaspoons, not three.
Cooking Measurement Converter
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Volume only — conversion to grams requires ingredient density and is handled by the cups-to-grams calculator.
- Recipes rarely state which cup standard they mean; the country of publication is usually the only clue.
- Traditional measures such as the Japanese gō are approximate by nature.
- Measuring technique, especially scooping versus spooning flour, introduces more error than any of these definitions.
In short: A ‘cup’ is not one volume. It is 236.59 mL in a traditional US recipe, 240 mL on a US nutrition label, 250 mL in Australia, New Zealand and Canada, 200 mL in Japan and 284.13 mL in an old British book — a spread of 84 mL, more than a third of a cup. The sharpest trap is the Australian tablespoon of 20 mL, which is FOUR teaspoons when every other system makes it three.
Formula
Every factor here is exact by definition, not measured. The US fluid ounce is defined as 29.5735295625 mL and the imperial gallon as 4.54609 litres exactly.
Worked Example
- Convert to millilitres first. 1 US cup × 236.5882365 = 236.5882365 mL.
- Divide by the target unit. 236.5882365 ÷ 250 = 0.9464 metric cups.
- Notice the gap. A US cup is about 5.67 % smaller than a metric cup.
- Check the spoon separately. A tablespoon is 3 teaspoons — unless the recipe is Australian, when it is 4.
- Prefer grams for solids. Volume cannot describe flour reliably at any precision.
The 20 mL tablespoon that ruins cakes. An Australian recipe calls for one tablespoon of baking powder. A British cook reads ‘tablespoon’, reaches for a 15 mL spoon, and is 25 % short. Run it the other way and it is worse: an Australian cook following a British recipe delivers 20 mL where 15 was wanted, a third more raising agent than the flour can carry, and the cake rises fast, collapses, and tastes metallic. Neither cook made a mistake — they used the correct tablespoon for their own country. Australia is the only country that redefined the tablespoon as four teaspoons when it went metric, and that single decision is responsible for more failed baking than any other unit difference in the kitchen.
Strengths & Limits Of This Model
Where this engine is strong
- Treats the cup as five different units rather than pretending it is one.
- Flags the Australian 20 mL tablespoon, the most damaging measurement trap in home baking.
- Every factor is an exact legal definition, not a rounded chart value.
Where it stops
- Cannot convert volume to weight without knowing the ingredient.
- Does not model packing, sifting or scooping technique.
- Traditional and regional measures beyond those listed are out of scope.
Practical Use Cases
Cooking from an overseas recipe
Establishing whether a ‘cup’ means 236.59, 240, 250, 200 or 284 mL before anything goes in the bowl.
Following an Australian recipe abroad
Catching the 20 mL tablespoon before it doubles your baking powder.
Reading an old British cookbook
Imperial cups and pints are 20 % larger than their American namesakes.
Scaling a recipe accurately
Convert once to millilitres, then scale — pair with the Recipe Scaling Calculator and, for solids, the Cups to Grams Calculator.
Methodology & Editorial Standards
All factors are exact definitions rather than measurements. The US fluid ounce is 29.5735295625 mL by definition, so the US customary cup of eight fluid ounces is exactly 236.5882365 mL, the US tablespoon is a sixteenth of that at 14.78676478125 mL, and the US teaspoon a third of the tablespoon. The US legal cup used for nutrition labelling is defined as exactly 240 mL. The imperial gallon is exactly 4.54609 litres, giving an imperial fluid ounce of 28.4130625 mL and an imperial cup, being ten fluid ounces, of 284.130625 mL. Metric spoons are exactly 5, 10 and 15 mL, the Australian tablespoon exactly 20 mL, and the metric cup exactly 250 mL. The Japanese cup is 200 mL and the gō used for rice is approximately 180.39 mL. This converter handles VOLUME ONLY and deliberately does not convert to weight, because that requires the density of a specific ingredient in a specific state of packing; the cups-to-grams and ingredient conversion calculators address that properly. All conversion factors are exact by definition under the International System of Units, or exact by international agreement where the unit is defined by treaty. Values are held at full IEEE-754 double precision internally and rounded only for display, so chained conversions do not accumulate drift.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Cooking Measurement Converter — 9 Expert FAQs
9 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
Is an Australian tablespoon really different?
Yes, and it is the most consequential difference in the kitchen. The Australian tablespoon is 20 mL, which is four 5 mL teaspoons. Every other metric country uses 15 mL, or three teaspoons, and the US tablespoon is 14.7868 mL. Australia is the only country that made the tablespoon four teaspoons on metrication. On raising agents, salt and spices, that 33 % difference is enough to ruin the dish.
How many mL is one cup?
It depends entirely on the recipe's origin. A US customary cup is 236.5882365 mL, a US legal cup used on nutrition labels is exactly 240 mL, a metric cup in Australia, New Zealand, Canada and South Africa is 250 mL, a Japanese cup is 200 mL, and an old imperial British cup is 284.130625 mL. That is a spread of 84 mL between the largest and the smallest.
What is the difference between a US customary and a US legal cup?
The customary cup is eight US fluid ounces, which works out at the awkward 236.5882365 mL. The legal cup is defined as exactly 240 mL and is what US nutrition labelling uses, because round numbers make label arithmetic sane. The legal cup is about 1.4419 % larger. For home cooking the difference is negligible; for label compliance it is not.
Does it matter if I use the wrong cup?
It matters less than people fear, provided you use the SAME wrong cup for everything. Recipes are largely about ratios, so measuring every ingredient with a 250 mL cup when the author meant 236.59 mL simply produces a slightly larger batch. The damage comes from mixing standards in one recipe, or from a small-quantity ingredient like yeast or salt where the absolute amount matters.
Why don't professional bakers use cups at all?
Because volume cannot describe a solid reliably. A cup of flour varies by roughly 20 % between scooped and spooned, and by more between a compacted bag and a freshly sifted one. Weight has no such ambiguity: 120 grams of flour is 120 grams however it got into the bowl. Every serious bakery works in grams and in baker's percentages.
What is a Japanese rice cup?
The gō, approximately 180.39 mL, is a traditional Japanese measure and is the cup supplied with a rice cooker. It is not the same as the Japanese cooking cup of 200 mL, and it is definitely not a US cup. Rice cooker water lines are calibrated to the gō, which is why using a different cup to measure the rice throws the water ratio out.
How do I convert an imperial recipe?
Multiply by 1.2 to get the American equivalent, roughly. An imperial cup is 284.130625 mL against the American 236.5882365, so imperial measures are about 20 % larger. Imperial appears in British cookbooks published before the 1970s; modern British recipes use grams and millilitres and are far easier to follow.
Is a dessertspoon a real measurement?
Yes, it is a metric 10 mL, sitting exactly between the 5 mL teaspoon and the 15 mL tablespoon. It survives mostly in British, Australian and Irish recipes and in medicine dosing. If you have no dessertspoon, two teaspoons is the exact equivalent.
Why is the US fluid ounce not the same as the imperial one?
They descend from different gallons. The US gallon is the old English wine gallon of 231 cubic inches, while the imperial gallon was redefined in 1824 as 4.54609 litres, the volume of ten pounds of water. So the US fluid ounce is 29.5735295625 mL and the imperial is 28.4130625 mL — the imperial ounce is smaller, yet the imperial pint of 20 ounces is larger than the American pint of 16.