Cups to Grams: Flour, Sugar & Butter Conversions

If you have ever tried to bake an American recipe in a British kitchen, you will know the problem straight away: the recipe says “1 cup of flour” but your kitchen scale reads in grams and your measuring jug reads in millilitres. Cups measure volume, while most UK and European recipes work in weight (grams). Because a cup of flour weighs very differently from a cup of sugar, you cannot use a single number for everything.

This guide gives you the reliable cup-to-gram figures for the ingredients you use most, a quick chart you can bookmark, and a worked example so you can convert a full recipe with confidence.

Why cups and grams are not the same for every ingredient

A cup is a measure of space. A standard US cup holds about 236.6 millilitres (roughly 240 ml, or 8.3 fl oz). But how much that space weighs depends on how heavy the ingredient is. Fill a cup with light, airy flour and it might weigh 120–125 grams (about 4.4 oz). Fill the same cup with granulated sugar and it weighs around 200 grams (7 oz), because sugar crystals are denser and pack together more tightly.

One more thing to watch: the “cup” is not identical everywhere. The US cup is 236.6 ml, the metric/Australian cup is 250 ml, and older British recipes sometimes used a 284 ml imperial cup. The figures below use the standard US cup, which is what most online recipes assume.

Cup-to-gram chart for common baking ingredients

These are widely accepted reference weights for 1 standard US cup. Use them as a dependable starting point:

• Plain / all-purpose flour: about 120–125 g (4.2–4.4 oz)
• Granulated (caster) sugar: about 200 g (7.1 oz)
• Icing / powdered sugar: about 120 g (4.2 oz)
• Light brown sugar, packed: about 220 g (7.8 oz)
• Butter: about 227 g (8 oz) — this equals 2 US sticks
• Milk or water: about 240 g / 240 ml (8.5 fl oz)
• Rolled oats: about 90 g (3.2 oz)
• Cocoa powder: about 100 g (3.5 oz)

Notice that flour and milk look similar in cups but are very different in grams — that is exactly why a single conversion factor never works.

How to convert a recipe from cups to grams: step by step

1. List every ingredient given in cups. Write down the exact fraction, such as ½ cup or 1¾ cups.
2. Find the correct weight for one cup of that specific ingredient from the chart above. Do not reuse the flour figure for sugar.
3. Multiply the number of cups by the per-cup weight. For example, 2 cups of flour at 125 g = 250 g.
4. For fractions, multiply the same way. ¾ cup of sugar is 0.75 × 200 g = 150 g.
5. Weigh, do not scoop, for accuracy. A kitchen scale removes the guesswork that comes from how firmly you pack a cup.

Worked example: an American cookie recipe in grams

Say a US recipe calls for the following, and you want everything in grams:

• 2 cups plain flour → 2 × 125 g = 250 g
• 1 cup granulated sugar → 1 × 200 g = 200 g
• ½ cup light brown sugar (packed) → 0.5 × 220 g = 110 g
• 1 cup butter → 1 × 227 g = 227 g (2 sticks)
• ¾ cup rolled oats → 0.75 × 90 g = 68 g

In under a minute you have turned a cup-based recipe into a precise, weighable ingredient list — no measuring cups required. If you prefer ounces, simply divide any gram figure by 28.35 (so 250 g of flour is about 8.8 oz).

A note on measuring flour accurately

Flour is the ingredient most likely to trip you up. If you dip the cup into the bag and scoop (the “scoop and sweep” method), you compress the flour and can end up with 130 grams or more per cup. If you spoon the flour lightly into the cup and level it off, you get closer to 120 grams. That difference of 10–15 grams per cup is enough to make a cake dense or a biscuit crumbly. Weighing in grams sidesteps the problem entirely, which is why professional bakers almost always work by weight.

Frequently asked questions

How many grams is 1 cup of flour in the UK?

Around 120–125 grams for plain (all-purpose) flour, using a standard US cup. If a recipe uses a 250 ml metric cup, the figure is slightly higher, closer to 130 grams. When in doubt, weigh it.

Is a US cup the same as a UK cup?

Not quite. A US cup is 236.6 ml and a metric cup (used in the UK, Australia and New Zealand) is 250 ml — about 5% larger. For most everyday baking the difference is small, but for precise work it is safer to convert to grams.

Why do professional bakers weigh ingredients instead of using cups?

Weighing is consistent. Two people using cups can measure noticeably different amounts of the same ingredient depending on how they scoop and pack it. Grams give the same result every time, which is why weight-based recipes are more reliable.

Convert any measurement in seconds

Once you know that different ingredients weigh different amounts per cup, converting a recipe is quick — but a tool makes it instant. Our free Cooking Measurement Converter handles cups, grams, millilitres, ounces, tablespoons and teaspoons for flour, sugar, butter and more, so you can switch any recipe between US and metric units without doing the maths by hand. Bookmark it for the next time a recipe and your kitchen scale disagree.