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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Weight and volume conversions beyond cups
Some older recipes use ounces, pounds and pints. These standard conversions help:
| Measure | Metric |
|---|---|
| 1 oz | about 28 g |
| 4 oz | about 113 g |
| 8 oz | about 227 g |
| 1 lb (16 oz) | about 454 g |
| 1 UK pint (20 fl oz) | about 568 ml |
| 1 US pint (16 fl oz) | about 473 ml |
The UK and US fluid ounce differ slightly (about 28.4 ml and 29.6 ml), so a pint is not the same on both sides of the Atlantic. When a recipe lists a pint of milk, check where it comes from. For rough scaling, 1 ml of water or milk weighs about 1 g, which does not hold for oil, honey or syrup. Our unit converter handles these conversions for you.
Celsius to Fahrenheit by formula
If your recipe gives a temperature that is not in the usual table, multiply Celsius by 9, divide by 5 and add 32. For Fahrenheit to Celsius, subtract 32, multiply by 5 and divide by 9.
| Celsius | Fahrenheit |
|---|---|
| 150°C | 302°F |
| 160°C | 320°F |
| 180°C | 356°F |
| 190°C | 374°F |
| 200°C | 392°F |
| 220°C | 428°F |
American recipes round to the nearest 25°F, so 356°F is written as 350°F, and 392°F as 400°F. For gas marks outside the three in this guide, use the chart in your oven’s manual, as gas ovens differ.
Worked example 2: a UK recipe for an American friend
Suppose a UK sponge recipe uses 225 g self-raising flour, 225 g caster sugar, 225 g butter and bakes at 160°C fan. Because the recipe is by weight, it works as written.
- A US cook with only cup measures would use roughly 1.8 cups of flour (225 ÷ 125), 1.1 cups of caster sugar (225 ÷ 200) and just under 1 cup of butter (225 ÷ 227). The uneven figures are why weighing is better.
- A fan setting of 160°C equals roughly 180°C conventional (add about 20°C), which is 356°F, or 350°F on an American oven dial.
If you do not have scales, convert once, write the cup figures on the recipe, and level each cup with a knife.
Why the same recipe can still turn out differently
- Dark or non-stick tins absorb heat faster, so bakes can brown sooner. Check early.
- Glass dishes retain heat; many bakers lower the oven setting a little. Check your recipe or the dish’s instructions.
- Oven position: the top is hottest; a baking tray on the middle shelf gives the most even result.
- Preheating: let the oven reach temperature fully. Many oven lights go off before the heat has settled.
- Opening the door drops the temperature and can make a cake sink.
Common mistakes
- Using a US cup in a metric recipe, or the reverse, without adjusting.
- Heaping the spoon: use level spoons unless a recipe says otherwise.
- Forgetting the fan: a 200°C recipe in a fan oven at 200°C can burn.
- Trusting the dial. An oven thermometer is cheap and shows if your oven runs hot or cold.
- Scaling baking times with quantities. Doubling a cake mix does not double the time; check the cake is cooked by looking and testing.
Scaling recipes safely
Multiply every ingredient by the same factor, but treat salt, spices and raising agents cautiously, as they do not always scale in a straight line. Use How to calculate percentages for the maths. A bigger tin or a deeper layer also changes the baking time. A hotter oven also costs more to run; How much does an appliance cost to run? shows how to estimate that.
Note: For meat, poultry, eggs and reheated rice, follow the temperatures and times given by the NHS and on the packaging, not a conversion alone.
Quick conversions for the kitchen
These small conversions come up again and again:
- A pinch is not a standard measure, so treat it as a small amount to taste.
- 3 teaspoons equal 1 tablespoon (5 ml × 3 = 15 ml).
- 16 tablespoons equal 1 US cup if you use 15 ml tablespoons and 237 ml cups, roughly, since 16 × 15 = 240 ml.
- Half a cup is about 118 ml for a US cup; a quarter cup is about 59 ml.
- 100 g of flour is a little under a cup, at 125 g per cup.
- For butter, a US stick is about half a cup, so roughly 113 g.
When a recipe is for a tin of a different size, use the same depth of mixture and watch the bake time rather than assuming the original time still applies. A shallower layer cooks faster; a deeper one needs longer at a slightly lower heat so the outside does not burn before the middle sets.
Storing and measuring ingredients well
Flour packs down in storage, so fluff it with a fork before spooning it into a cup. Brown sugar is usually pressed into the cup in American recipes, which makes it heavier than loosely poured sugar. Liquids go in a jug read at eye level, not a dry measuring cup. Honey and syrup stick to spoons, so lightly oil the spoon or warm it first. If you often convert between systems, keep a weight-based version of your favourite recipes, because grams do not change with how you scoop.
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.
How many grams are in an ounce?
About 28 g (28.35 g more exactly). For recipes, many people round to 25 g or 30 g, but when a recipe says 4 oz, use about 113 g.
What is 180°C in Fahrenheit?
180°C is 356°F, which US recipes usually write as 350°F.
Is a tablespoon the same everywhere?
Our calculator uses 15 ml for a tablespoon and 5 ml for a teaspoon. Some countries use a different tablespoon size, so check where the recipe is from.
Do I convert the oven temperature for a fan oven in Fahrenheit?
Yes, the same idea applies. Reduce the conventional temperature by about 25°F, or follow your oven’s manual.