Cooking Conversion Calculator
Convert between grams, cups and ounces, millilitres and fluid ounces, oven temperatures in °C, °F and gas mark, and spoons. Built for UK kitchens following recipes from anywhere.
Cooking converter
Choose a mode, enter a value, get the conversion instantly.
Cup weights vary by ingredient — values are typical UK kitchen estimates.
Why cooking conversions trip everyone up
British home cooks live in two worlds. We grew up with grams, millilitres and gas marks, yet the internet is full of American recipes that measure flour and sugar in cups and set ovens in Fahrenheit. Translating between the two is fiddly because a cup is a measure of volume, not weight. One cup of feathery flour weighs far less than one cup of dense sugar, so there is no single "grams in a cup" answer. This converter handles each ingredient correctly and covers temperature and spoon measures too.
The everyday anchors: 1 US cup ≈ 240ml, 1 oz ≈ 28.35g, 1 UK tbsp = 15ml, 1 tsp = 5ml, and gas mark 4 = 180°C = 350°F.
Weight and cup conversions
For dry ingredients, weighing in grams is always the most accurate method, which is why UK baking books use scales. When a recipe only gives cups, use a per-ingredient weight: plain flour is about 125g per cup, caster sugar 200g, brown sugar 220g, butter 227g (half a US stick is roughly 113g), and rolled oats 100g. Liquids like water and milk are about 240g per cup since they are close to the density of water. Our calculator lets you pick the ingredient so the cup-to-gram answer is realistic rather than a one-size-fits-all guess.
Oven temperatures: °C, °F and gas mark
UK ovens often show gas marks while recipes quote Celsius or Fahrenheit. The conversion is non-linear at the edges but the common baking band is easy to remember.
| Gas mark | °C | °F | Use |
|---|---|---|---|
| 2 | 150 | 300 | Slow |
| 4 | 180 | 350 | Moderate |
| 6 | 200 | 400 | Fairly hot |
| 7 | 220 | 425 | Hot |
| 9 | 240 | 475 | Very hot |
Remember that a fan (convection) oven runs hotter. If a recipe is written for a conventional oven, drop the temperature by about 20°C — roughly one gas mark — to avoid over-browning.
Volume and spoon measures
For liquids, 1 fluid ounce is about 28.4ml and a UK pint is 568ml (larger than a US pint of 473ml). Spoons are standardised in cooking: a UK tablespoon is 15ml and a teaspoon is 5ml, so three teaspoons make a tablespoon. These are level spoons unless a recipe says "heaped". When precision matters — in baking especially — weighing beats spooning every time.
Getting consistent results
The golden rule is to pick one system and stick to it for the whole recipe rather than mixing cups and grams mid-bake. Use this converter to translate the whole ingredient list up front, jot the metric figures next to each line, and cook from those. For official UK measurement guidance and food standards, see GOV.UK.
Frequently asked questions
How many grams are in a cup?
It depends on the ingredient. One US cup is about 200g of caster sugar, 125g of plain flour, or 240g of water, because a cup measures volume, not weight.
What is gas mark 4 in Celsius?
Gas mark 4 is 180°C (350°F), the standard moderate baking temperature for many cakes and roasts.
How do I convert Fahrenheit to Celsius for an oven?
Subtract 32 from the Fahrenheit figure and multiply by 5/9. So 350°F becomes (350 − 32) × 5/9 = 177°C, usually rounded to 180°C.
How many millilitres are in a UK tablespoon?
A UK tablespoon is 15ml and a UK teaspoon is 5ml, so there are three teaspoons in a tablespoon.
Should I reduce the temperature for a fan oven?
Yes. A fan (convection) oven runs hotter, so reduce the conventional temperature by about 20°C, or one gas mark, for the same result.