Quick answer: To convert an American recipe for a UK kitchen, weigh dry ingredients (1 cup of plain flour is about 120 g, sugar about 200 g, butter 227 g), measure liquids in millilitres (1 US cup is 236.6 ml), convert °F to °C and take 20°C off for a fan oven, then swap US ingredient names for British ones.
American recipes are written for a measuring system that looks familiar but is not quite the one used in Britain. Cups measure volume rather than weight, US pints are smaller than UK pints, ovens are marked in Fahrenheit and some ingredients go by different names. This guide walks through the conversion one step at a time and fits alongside the other charts in the UK cooking measurements guide.
What you need
- Digital kitchen scales that read in 1 g steps. This is the single most useful tool for American recipes.
- A measuring jug marked in millilitres.
- Metric measuring spoons (15 ml tablespoon, 5 ml teaspoon).
- A set of US measuring cups (optional). Useful if you bake from American books often, but scales are more accurate.
- A ruler or tape measure for checking tin sizes, and an oven thermometer if you suspect your dial is out.
How do you convert an American recipe step by step?
Convert in a fixed order: dry ingredients, liquids, spoons, butter, oven, then names and tins. Writing the UK figures next to the originals before you start cooking saves mistakes halfway through a bake.
- Read the recipe and mark every US unit. Look for cups, sticks, ounces, pints, quarts, °F and pan sizes in inches. Note whether “ounces” means weight (oz) or volume (fl oz); American recipes use both.
- Convert dry ingredients to grams. A cup is a volume, and a cup of flour weighs far less than a cup of sugar, so there is no single cups-to-grams figure. Use the ingredient table below. Small amounts such as ¼ cup of cocoa can be scaled from the same figures.
- Convert liquids to millilitres. One US cup is 236.6 ml, so 240 ml is a close and convenient working figure. A US pint is 473 ml, about 95 ml less than a UK pint of 568 ml. A US fluid ounce is 29.6 ml, slightly more than a UK fluid ounce of 28.4 ml.
- Keep spoon measures as they are. A US tablespoon is 14.8 ml and a US teaspoon 4.9 ml. Standard UK spoons hold 15 ml and 5 ml, so the difference is too small to matter in home cooking.
- Convert butter sticks. One US stick is a quarter of a pound: 113 g, half a cup or 8 tablespoons. Two sticks (1 cup) are 227 g, just under a standard 250 g British block.
- Convert the oven temperature. Turn Fahrenheit into Celsius, round to the nearest 10°C, and subtract about 20°C if you use a fan. The Celsius to Fahrenheit oven temperatures chart lists every common setting, and 350°F, the most common of all, is 180°C, 160°C fan or gas mark 4.
- Swap ingredient names. Use the translation table further down. Watch for products that sound the same but are not, such as self-rising flour and heavy cream.
- Match the tin size. American pans are sold in inches. Multiply by 2.54 to get centimetres and pick the nearest UK tin. Measure across the inside top edge with a tape measure, reading it correctly, rather than trusting the label.
- Adjust the eggs if needed. A US large egg must average at least 56.7 g (24 oz per dozen), which puts it in the UK medium band of 53 g to 63 g. In most recipes a UK medium or large egg works, but for egg-heavy bakes, use medium.
How many grams are in a cup of common baking ingredients?
It depends on the ingredient: a cup of plain flour is about 120 g, while a cup of granulated sugar is about 200 g. The figures below follow the King Arthur Baking ingredient weight chart, a widely used American reference, and assume flour is spooned into the cup and levelled rather than scooped.
| US ingredient | UK name | 1 cup | ½ cup | ¼ cup |
|---|---|---|---|---|
| All-purpose flour | Plain flour | 120 g | 60 g | 30 g |
| Bread flour | Strong white flour | 120 g | 60 g | 30 g |
| Granulated sugar | Granulated sugar | 198 g | 99 g | 50 g |
| Brown sugar (packed) | Soft brown sugar | 213 g | 107 g | 53 g |
| Confectioners’ sugar | Icing sugar | 113 g | 57 g | 28 g |
| Butter | Butter | 227 g | 113 g | 57 g |
| Unsweetened cocoa | Cocoa powder | 84 g | 42 g | 21 g |
| Rolled oats | Porridge oats | 89 g | 45 g | 22 g |
| Chocolate chips | Chocolate chips | 170 g | 85 g | 43 g |
| Milk | Milk | 227 g (236.6 ml) | 113 g | 57 g |
Other reliable references round some of these differently, for example 125 g for a cup of flour or 200 g for sugar. A difference of a few grams per cup rarely changes a result. If you have no scales at all, the guide to measuring 100 g of flour without scales explains spoon-based methods.
How do US cups, pints and spoons compare with UK measures?
US liquid measures are all slightly smaller than their British namesakes, except the fluid ounce. The US cup sits close to, but below, the 250 ml metric cup used in Australian and some Canadian recipes, and well below the old British cup of half an imperial pint.
| Measure | US size | UK (imperial) size | Difference |
|---|---|---|---|
| Teaspoon | 4.93 ml | 5 ml | Negligible |
| Tablespoon | 14.79 ml | 15 ml | Negligible |
| Fluid ounce | 29.57 ml | 28.41 ml | US is about 4% larger |
| Cup | 236.59 ml | No modern UK cup | Use 240 ml |
| Pint | 473.18 ml | 568.26 ml | UK is 20% larger |
| Quart | 946.35 ml | 1,136.52 ml | UK is 20% larger |
| Gallon | 3.785 litres | 4.546 litres | UK is 20% larger |
One US cup equals 236.6 millilitres, or about 8.3 UK fluid ounces. If a recipe gives liquids in fluid ounces, the ml to fl oz converter lets you switch between US and UK fluid ounces.
What are American ingredients called in the UK?
Most differences are just names, but a few products are genuinely different and need a substitute. The table flags the ones that change how a recipe behaves.
| US name | UK equivalent | Notes |
|---|---|---|
| All-purpose flour | Plain flour | Direct swap |
| Self-rising flour | Self-raising flour plus a pinch of salt | US self-rising flour contains salt; UK self-raising usually does not |
| Cake flour | Plain flour with some cornflour | No exact UK product |
| Baking soda | Bicarbonate of soda | Direct swap |
| Cornstarch | Cornflour | Direct swap |
| Confectioners’ or powdered sugar | Icing sugar | Direct swap |
| Superfine sugar | Caster sugar | Direct swap |
| Heavy cream | Whipping or double cream | US heavy cream is at least 36% fat; UK whipping cream at least 35%, double cream at least 48% |
| Half-and-half | Equal parts single cream and whole milk | No exact UK product |
| Light corn syrup | Golden syrup | Different flavour; usually fine in small amounts |
| Molasses | Black treacle | Close substitute |
| Graham crackers | Digestive biscuits | Common swap for cheesecake bases |
| Semisweet chocolate | Dark chocolate | Check cocoa percentage |
| Zucchini, eggplant, cilantro, scallions | Courgette, aubergine, coriander, spring onions | Direct swaps |
What size UK tin replaces an American pan?
Multiply the inch size by 2.54 and choose the nearest UK tin, which is usually sold in whole centimetres. A 9-inch round pan is 22.9 cm across, so a 23 cm tin is the match.
| US pan | Exact metric size | Nearest UK tin |
|---|---|---|
| 8 in square | 20.3 cm | 20 cm square |
| 9 in round | 22.9 cm | 23 cm round |
| 9 × 13 in rectangular | 22.9 × 33.0 cm | 23 × 33 cm traybake tin |
| 9 × 5 in loaf | 22.9 × 12.7 cm | 23 × 13 cm loaf tin |
| 10 in tube or Bundt | 25.4 cm | 25 cm ring tin |
If your tin is a little larger, the mixture will be shallower and bake faster; if smaller, it will be deeper and take longer. Check a few minutes early either way.
Worked example: converting a cookie recipe
Here is a typical American chocolate chip cookie ingredient list converted line by line. The weights use the table above and are rounded to the nearest gram.
| US recipe | UK version | How it was converted |
|---|---|---|
| 2¼ cups all-purpose flour | 270 g plain flour | 2.25 × 120 g |
| 1 tsp baking soda | 1 tsp bicarbonate of soda | Spoons unchanged |
| 1 cup (2 sticks) butter | 227 g butter | 2 × 113.4 g |
| ¾ cup granulated sugar | 149 g granulated sugar | 0.75 × 198 g |
| ¾ cup packed brown sugar | 160 g soft brown sugar | 0.75 × 213 g |
| 2 large eggs | 2 medium eggs | US large ≈ UK medium |
| 2 cups chocolate chips | 340 g chocolate chips | 2 × 170 g |
| Bake at 375°F | 190°C, 170°C fan, gas mark 5 | (375 − 32) × 5 ÷ 9 = 190.6°C |
Common mistakes to avoid
- Treating ounces and fluid ounces as the same thing. Eight ounces of chocolate is a weight (227 g); eight fluid ounces of milk is a volume (236.6 ml in a US recipe).
- Scooping flour straight from the bag. Pushing the cup into the flour packs it down and can add a significant amount extra. Weigh it, or spoon it in and level it off.
- Using a UK pint for a US pint. The British pint is 95 ml bigger, enough to turn a custard or batter runny.
- Reducing for a fan oven twice. Convert 350°F to 180°C, then take 20°C off once. Do not start from a figure already marked “fan”.
- Using a 250 ml measuring cup. Metric cups sold in some shops hold 250 ml, about 6% more than a US cup. Check the markings on cup sets before relying on them.
- Forgetting the salt in self-rising flour. If a US recipe uses self-rising flour and adds no salt, add a pinch when you use UK self-raising flour.
If a recipe also gives weights in ounces or pounds, the pounds to kilograms converter handles larger quantities such as a joint of meat.
Frequently asked questions
Is a US cup the same as a UK cup?
No. A US cup is 236.6 ml. The UK has no official cup today, and older British recipes that mention a cup usually meant half an imperial pint, 284 ml. Metric cups are 250 ml.
How many grams is 1 cup of flour in the UK?
One US cup of plain flour weighs about 120 g when spooned in and levelled. Some references use 125 g. Scooped flour can weigh noticeably more, so scales give the most reliable result.
Is an American tablespoon the same as a UK tablespoon?
Almost. A US tablespoon is 14.8 ml and a UK tablespoon is 15 ml, so you can use UK spoons without adjusting. Australian tablespoons are different, at 20 ml.
What is heavy cream in the UK?
US heavy cream has at least 36% milk fat. UK whipping cream, at a minimum of 35%, is the closest match. Double cream, at 48% or more, also works for most recipes but is richer.
Do I need to change American oven temperatures?
Yes. Convert Fahrenheit to Celsius and round to the nearest 10°C, then subtract about 20°C for a fan oven. For example, 350°F becomes 180°C, or 160°C fan.
Are American eggs the same size as British eggs?
Not quite. A US large egg averages at least 56.7 g, which falls in the UK medium band of 53 g to 63 g. Use UK medium eggs when a US recipe asks for large.
Sources
- King Arthur Baking: ingredient weight chart
- NIST: US customary to metric conversions
- Food Labelling Regulations 1996, Schedule 8 Part III (cream fat content), legislation.gov.uk
- US Code of Federal Regulations 21 CFR 137.180 (self-rising flour)
- British Egg Information Service: egg sizes