Cooking Measurements Converter
Recipes are messy. American books say cups, British ones say grams, gran's recipe card says "a cup of flour" and refuses to elaborate. This tool converts volumes, weights and oven temperatures across UK, US and metric conventions, plus a separate ingredient block for the cup-to-grams question that catches everyone out.
Explain like I'm 5 (which cup, which spoon)
Cups and spoons are not the same size everywhere. A US cup is 240 ml. The "metric cup" used in the UK and Australia is 250 ml. UK and US tablespoons are different too. So pick the convention your recipe was written in (US, UK, or metric), then convert to whatever your kitchen kit is actually marked in. For baking, weigh things in grams if you can. It is the single biggest upgrade you can make.
Cup, tablespoon and teaspoon convention
Pick which "cup", "tbsp" and "tsp" the recipe is using. This applies to the volume converter and the cup-to-grams block below. Default is metric (250 ml cup, 15 ml tbsp, 5 ml tsp).
Volume
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Weight
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Temperature and gas mark
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Cups to grams (by ingredient)
Density depends on the ingredient. A cup of flour weighs less than a cup of sugar; a cup of honey is heavier still. These figures are typical, not laws of physics: expect ±5% variation depending on packing, grind, and how humid your kitchen is. Cup size follows the convention picked above.
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Volume base unit: 1 ml. US fluid ounce = 29.5735 ml; UK fluid ounce = 28.4131 ml; US pint = 473.176 ml; UK pint = 568.261 ml. Weight: 1 oz = 28.3495 g; 1 lb = 453.592 g. Temperature: F = C × 9/5 + 32. Gas mark conversions follow the conventional UK gas oven scale (mark 4 = 180 C). Ingredient densities sourced from King Arthur Baking Company, cross-referenced with BBC Good Food.
Why UK and US measurements diverged
Until 1824 the British and Americans used roughly the same set of units, the wine gallon and Queen Anne measures inherited from English common practice. Then the UK's Imperial Units Act tidied everything up: the imperial gallon was redefined as the volume of ten pounds of water, which works out at 4.546 litres. The Americans, having politely declined to take orders from London since 1776, kept the older "Queen Anne" gallon at 3.785 litres. Same word, different size, ever since.
That difference cascades. A US pint is 16 fl oz at 29.57 ml each (473 ml total). A UK pint is 20 fl oz at 28.41 ml each (568 ml total). Even the fluid ounces are not the same, because each is one-twentieth or one-sixteenth of its respective pint, and the pints disagree. This is also why a British pint glass holds more beer than an American one. You are welcome.
The cup is messier still. The US legal cup is 240 ml (used on nutrition labels); the customary US recipe cup is 236.6 ml; the modern "metric cup" used in the UK, Australia and New Zealand is 250 ml, chosen because it makes the maths easier. The historic UK imperial cup was 284 ml (half an imperial pint), but you will rarely see it in modern recipes. This tool defaults to the 250 ml metric cup. Switch the convention selector if your recipe is American.
Why baking by weight is more accurate than by volume
A cup of flour is not a fixed weight. If you sift the flour, spoon it lightly into the cup and level it off, you get about 120 g. If you scoop the cup straight into the bag and pack it down, you can hit 150 g or more. That is a 25% range on a single ingredient, in a recipe that probably also calls for sugar, butter and eggs measured the same way. By the time you have stacked four or five "approximately" ingredients, the dough you made bears only a passing resemblance to the one the recipe writer tested.
For stew this does not matter. For cake, bread, pastry or biscuits, it absolutely does. A digital kitchen scale costs less than a takeaway and removes the entire problem. Pros weigh; you should too.
Gas mark to Celsius and Fahrenheit
Gas mark is a UK gas oven scale, calibrated so each mark is roughly 25 F apart. Conventional oven figures below; for a fan (convection) oven, drop the Celsius figure by about 20 C, or shave 10 to 15 minutes off the cooking time.
| Gas mark | Celsius | Fahrenheit | Description |
|---|---|---|---|
| 1/4 | 110 C | 225 F | Very cool (slow drying) |
| 1/2 | 120 C | 250 F | Very cool |
| 1 | 140 C | 275 F | Cool |
| 2 | 150 C | 300 F | Cool |
| 3 | 170 C | 325 F | Warm |
| 4 | 180 C | 350 F | Moderate |
| 5 | 190 C | 375 F | Moderately hot |
| 6 | 200 C | 400 F | Hot |
| 7 | 220 C | 425 F | Hot |
| 8 | 230 C | 450 F | Very hot |
| 9 | 240 C | 475 F | Very hot |
Ingredient densities used here
These cup-to-gram figures are the values used in this tool, based on King Arthur Baking Company's ingredient weight chart cross-referenced with BBC Good Food. Treat them as central estimates with a realistic ±5% spread. Plain flour in particular varies wildly with how it is measured: sifted and lightly spooned versus scooped and packed.
| Ingredient | Grams per metric cup (250 ml) | Grams per US cup (240 ml) |
|---|---|---|
| Plain flour | 130 g | 125 g |
| Self-raising flour | 130 g | 125 g |
| Granulated sugar | 210 g | 200 g |
| Caster sugar | 210 g | 200 g |
| Brown sugar (packed) | 225 g | 215 g |
| Icing sugar | 125 g | 120 g |
| Butter | 237 g | 227 g |
| Rolled oats | 95 g | 90 g |
| Rice (uncooked) | 200 g | 190 g |
| Honey | 355 g | 340 g |
| Milk | 258 g | 248 g |
| Water | 250 g | 240 g |
Sticks of butter (the American thing)
US butter is sold in sticks. One stick is 113 g (4 oz, half a US cup, eight tablespoons). Two sticks make 227 g, four make 454 g (a pound). UK butter comes in 250 g blocks, so the maths never lines up cleanly. If your American recipe calls for "1 stick", weigh out 113 g. If it calls for "2 sticks softened", weigh 227 g. Done.
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Frequently asked questions
Is a UK cup the same as a US cup?
No. US cup is 240 ml (legal) or 237 ml (customary). The metric cup used in modern UK and Australian recipes is 250 ml. The historic UK imperial cup was 284 ml. If a recipe just says "cup" with no nationality given, default to US 240 ml.
How do I convert tablespoons accurately?
Metric tbsp is 15 ml, US is 14.79 ml, UK is 17.76 ml. Pick the convention this recipe was written in. For most cooking the differences are small; for baking powder, salt, or anything strong, they matter.
What is gas mark 4 in fan oven Celsius?
Gas mark 4 is 180 C conventional, which is roughly 160 C fan. As a rule, a fan oven runs about 20 C hotter than a conventional oven at the same setting, so drop the dial accordingly.
Why does my US recipe call for "sticks" of butter?
Because US butter ships in eight-tablespoon sticks. One stick is 113 g (4 oz). Two sticks is 227 g, four sticks is 454 g (a pound). UK butter is in 250 g blocks, so the maths never quite lines up.
Why is baking by weight more accurate than by volume?
A cup of flour can weigh anywhere from 120 g (sifted) to 150 g (packed). That is a 25% range on a single ingredient. A digital scale removes the variability and is the cheapest upgrade you can make to your baking.