For baking, weigh ingredients in grams where you can, because a cup of flour is about 125 g but varies with how it is packed. A US cup is 237 ml, a tablespoon is 15 ml and a teaspoon is 5 ml. For ovens, gas mark 4 is 180°C (350°F), gas mark 6 is 200°C (400°F) and a fan oven is usually set about 20°C lower.
Spoons and cups
These measures are the same for most recipes:
| Measure | Amount |
|---|---|
| 1 teaspoon | 5 ml |
| 1 tablespoon | 15 ml |
| 1 US cup | 237 ml |
| 1 UK/metric cup | 250 ml |
Be careful with recipes from different countries. An American recipe that says “1 cup” means about 237 ml, while a metric cup is 250 ml, a small but sometimes noticeable difference in baking.
Cups to grams for common ingredients
Cups measure volume, but ingredients differ in density, so the weight of a cup depends on what is in it. Here are the figures used by our Cooking conversions tool:
| Ingredient (1 US cup) | Approximate weight |
|---|---|
| Plain flour | 125 g |
| Caster sugar | 200 g |
| Butter | 227 g |
So 2 cups of flour is about 250 g, or 8.8 oz. These are guides only. Flour that has been scooped and packed can weigh noticeably more than flour spooned lightly into the cup, which is why weighing is more accurate.
Many cooks also need to convert ounces and pounds to grams. The Unit converter converter handles weight, volume, length and temperature, and it is handy for anything outside the list of cooking ingredients.
Oven temperatures: Celsius, Fahrenheit and gas mark
UK recipes often use Celsius or gas marks, while American recipes use Fahrenheit. These common settings are worth remembering:
| Gas mark | Celsius (conventional) | Fahrenheit |
|---|---|---|
| 4 | 180°C | 350°F |
| 6 | 200°C | 400°F |
| 7 | 220°C | 425°F |
The Oven temperature converter tool converts between all three and gives the nearest gas mark. For example, 350°F is about 177°C, which is the same as gas mark 4.
Fan ovens
A fan oven circulates hot air, so it cooks more evenly and quickly. As a rule, set a fan oven about 20°C (about 25°F) lower than the conventional temperature in the recipe. So a recipe that asks for 200°C in a conventional oven is 180°C in a fan oven. Gas marks apply to gas ovens, so there is no separate fan setting for them.
Ovens vary, so use an oven thermometer if your results are inconsistent. Always check the manufacturer’s instructions for your oven and the recipe.
Tips for accurate conversions
- Weigh dry ingredients on digital scales wherever you can.
- Level cups and spoons rather than heaping them.
- Check whether a recipe means a US cup or a metric cup.
- Convert the oven temperature before you preheat.
- Scale a recipe up or down by multiplying every ingredient by the same factor. The guide to How to calculate percentages is a handy refresher, and our guide to Macros for beginners: protein, carbs and fat shows how to turn ingredients into protein, carbohydrate and fat.
Note: Conversions are approximate and food safety matters. Follow the cooking temperatures and times on packaging and the NHS guidance for meat, eggs and rice.
Worked example: converting a US recipe
Say an American recipe calls for 2 cups of flour, 1 cup of caster sugar, 1 cup of butter and an oven at 350°F. In metric that is about 250 g flour, 200 g sugar and 227 g butter. The oven converts to roughly 177°C, so set a conventional oven to 180°C (gas mark 4), or about 160°C in a fan oven. Writing the converted quantities on the recipe before you start saves you from reaching for the cup measure mid-bake and keeps results consistent from one attempt to the next. Keep your converted version somewhere handy for next time.
Try the calculator
Use Cooking conversions for cups and spoons to grams and millilitres, Oven temperature converter for temperatures, and Unit converter for any other unit.
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Frequently asked questions
How many grams are in a cup of flour?
About 125 g for plain flour, but it depends on how it is packed. Weighing is more accurate.
What is gas mark 6 in Celsius?
Gas mark 6 is 200°C, or 400°F, in a conventional oven.
How much lower should I set a fan oven?
Usually about 20°C lower than the temperature for a conventional oven.
Is a US cup the same as a UK cup?
No. A US cup is 237 ml and a metric cup is 250 ml, so check which one a recipe uses.