How the cooking conversion calculator works
British recipes weigh dry ingredients in grams, while American recipes measure them by volume in cups. Because a cup of flour weighs much less than a cup of sugar, there's no single cups-to-grams figure: you need the weight of one cup of that particular ingredient. The calculator multiplies the number of cups by that weight:
grams = cups × grams in 1 US cup of the ingredient
Liquids, weights and oven temperatures are simpler, because they use fixed conversion factors. A US cup is 236.6ml (often rounded to 240ml on packaging), a UK fluid ounce is 28.4ml, a US fluid ounce is 29.6ml and an ounce of weight is 28.35g.
How many grams in a cup?
| Ingredient | 1 cup | ½ cup | ¼ cup |
|---|---|---|---|
| Plain or self-raising flour | 120g | 60g | 30g |
| Caster or granulated sugar | 200g | 100g | 50g |
| Brown sugar | 180g | 90g | 45g |
| Icing sugar | 100g | 50g | 25g |
| Butter | 225g | 113g | 56g |
| Rice, uncooked | 190g | 95g | 48g |
| Porridge oats | 90g | 45g | 23g |
| Cocoa powder | 85g | 43g | 21g |
These figures are the ones used in common UK kitchen conversion tables from flour millers and cookware retailers. In America, butter is sold in sticks: one stick is ½ cup, about 113g. Cup weights vary by a few grams depending on whether flour is sifted or packed down, so for baking it's worth weighing.
Liquid and spoon conversions
| Measure | Millilitres |
|---|---|
| 1 teaspoon (tsp) | 5ml |
| 1 tablespoon (tbsp) | 15ml |
| 1 UK fluid ounce | 28.4ml |
| 1 US fluid ounce | 29.6ml |
| 1 US cup | 236.6ml |
| 1 UK pint | 568ml |
Watch out for pints in American recipes: a US pint is 16 US fluid ounces (473ml), smaller than the 20-fluid-ounce UK pint. Australian recipes use a metric cup of 250ml and a 20ml tablespoon.
Ounces to grams
One ounce is 28.35g and one pound (16oz) is 453.6g. Older British recipes often round an ounce to 25g or 30g, which is fine as long as you stick to the same system for every ingredient.
- 4oz = 113g
- 8oz = 227g
- 12oz = 340g
- 1lb = 454g
Oven temperature conversion chart
| Gas mark | °C | °C fan | °F | Description |
|---|---|---|---|---|
| 1 | 140 | 120 | 275 | Cool |
| 2 | 150 | 130 | 300 | Cool |
| 3 | 160 | 140 | 325 | Moderate |
| 4 | 180 | 160 | 350 | Moderate |
| 5 | 190 | 170 | 375 | Moderately hot |
| 6 | 200 | 180 | 400 | Moderately hot |
| 7 | 220 | 200 | 425 | Hot |
| 8 | 230 | 210 | 450 | Hot |
| 9 | 240 | 220 | 475 | Very hot |
Fan ovens circulate hot air, so they're usually set about 20°C lower than a conventional oven. Many ovens run hotter or cooler than the dial says, so an oven thermometer is a cheap way to check.
Worked examples
- 2 cups of plain flour: 2 × 120g = 240g
- ¾ cup of caster sugar: 0.75 × 200g = 150g
- A US recipe says 350°F: that's gas mark 4, 180°C or 160°C fan
- 8oz of cheese: 8 × 28.35 = 227g
Cooking a Christmas dinner? The turkey cooking time calculator works out roasting times and oven temperatures for your bird. To scale a recipe up or down by a percentage, try the percentage calculator.
Frequently asked questions
How many grams is 1 cup of flour?
One US cup of plain or self-raising flour weighs about 120g, or 110g if it's sifted first. Weigh it if you can, because flour that's packed into the cup weighs more.
How many grams of sugar in a cup?
One cup of caster or granulated sugar is about 200g, a cup of brown sugar about 180g and a cup of icing sugar about 100g.
How many grams is a cup of butter?
One cup of butter is about 225g. Half a cup, which is one American stick of butter, is about 113g.
What is 180°C in gas mark?
180°C is gas mark 4, which is 160°C in a fan oven or 350°F.
How many ml in a tablespoon UK?
A UK tablespoon is 15ml and a teaspoon is 5ml, so there are three teaspoons in a tablespoon.
Last reviewed October 2026 using 2026/27 figures. This calculator gives an estimate for guidance only.