1/2 Cup in Grams: Conversion Guide for Common Ingredients

Standing in the kitchen with a recipe that calls for half a cup of something, you’ve likely wondered exactly how many grams that scoop should weigh, but the answer isn’t as simple as one number — it changes with every ingredient and even depends on which side of the Atlantic you’re baking on. This guide cuts through the confusion with specific, source-backed weights for flour, sugar, butter, and more, so your next batch turns out right every time.

“1/2 cup all-purpose flour = 63 grams.” — Allrecipes (recipe publisher)

“1/2 cup granulated sugar = 100 grams.” — Doves Farm (flour and baking authority)

1/2 cup all-purpose flour: 63 g ·
1/2 cup granulated sugar: 100 g ·
1/2 cup butter: 113 g ·
1/2 cup water: 120 g ·
US cup volume: 240 ml ·
UK cup volume: 284 ml

Eight key figures define the landscape: one clear pattern is that the same “half cup” can swing from 63 grams for flour to 120 grams for water — a near 2× difference.

How many grams is 1/2 a cup?

The short answer: there is no single number. A half cup of all-purpose flour weighs about 63 grams, while a half cup of granulated sugar is closer to 100 grams. The difference comes down to ingredient density — how tightly the particles pack into a volume measure.

Why cup size matters: US vs UK

• US cup: 236.6 ml, commonly rounded to 240 ml in recipes
• UK cup: 284 ml (10 imperial fluid ounces), per UK Government (official measurement standards)
• Difference: The UK cup is about 20% larger — using a US cup for a UK recipe can throw off ratios

Common ingredient weights for 1/2 cup

Seven ingredients, one rule: check the density. Water is the baseline at 120 grams per half cup because 1 ml of water weighs roughly 1 gram. Flour and sugar pack differently, so their gram weights differ sharply.

• All-purpose flour: 63 g (Allrecipes (recipe publisher))
• Granulated sugar: 100 g (Doves Farm (flour and baking authority))
• Butter: 113 g
• Water: 120 g
• Milk: approx 122 g
• Oatmeal (rolled oats): approx 45 g
• Rice (uncooked): approx 100 g

How to use a digital scale for accuracy

1. Place your bowl on the scale and tare (zero) it
2. Add ingredient until you reach the target gram weight
3. No need to worry about scooping technique — the scale eliminates volume errors

The implication: relying on volume alone introduces ambiguity that a scale resolves.

Is 250 g 1/2 cup?

No — this is one of the most common kitchen misconceptions. 250 grams is roughly 1 cup of water (since 1 ml of water ≈ 1 gram), not half a cup. For flour, 250 grams equals about 2 cups, not half.

The role of ingredient density

• Water has a density of 1 g/ml, so 250 ml (≈1 US cup) = 250 g
• All-purpose flour has a density of roughly 0.53 g/ml, so 250 g of flour fills about 2 cups
• Granulated sugar has a density of about 0.85 g/ml, so 250 g fills about 1.25 cups

Five data points illustrate the gap: for water, 250g equals about 1 cup; for flour, 250g equals about 2 cups; for sugar, about 1.25 cups. The density of each ingredient dictates the volume.

250g of water vs 250g of flour

• 250 g water ≈ 1 cup (240 ml)
• 250 g all-purpose flour ≈ 2 cups (480 ml by volume)
• Using a volume measure for flour when the recipe expects grams by weight yields a very different result

Why 250g is not a standard half-cup measurement

• 250 g is not equal to 1/2 cup for any common baking ingredient
• The only item close is something with a density near 2 g/ml, which no standard baking ingredient has
• Using 250 g as a half-cup shortcut would over-flour a recipe by roughly 4× (King Arthur Baking (baking education resource))

The pattern: density, not volume, determines the right gram count for your ingredient.

What is 1/2 cup in the UK?

In the United Kingdom, a cup measures 284 ml (UK Government (official measurement standards)), not the 240 ml used in the US. This means 1/2 UK cup equals 142 ml, which translates to roughly 142 grams of water.

UK cup measurement vs US cup

• UK cup: 284 ml (10 imperial fluid ounces)
• US cup: 236.6 ml (8 US fluid ounces)
• Difference: UK cup is about 20% larger by volume
• For flour: 1/2 UK cup ≈ 75 g vs 1/2 US cup = 63 g
• For sugar: 1/2 UK cup ≈ 120 g vs 1/2 US cup = 100 g

How UK recipes typically measure ingredients

• British cookbooks more commonly use grams and milliliters rather than cups (BBC Good Food (UK recipe authority))
• When cups do appear, they are UK cups unless otherwise specified
• Older UK recipes may use imperial pints, ounces, or pounds

Converting UK cups to grams for common ingredients

• 1/2 UK cup water: ~142 g
• 1/2 UK cup all-purpose flour: ~75 g
• 1/2 UK cup granulated sugar: ~120 g
• 1/2 UK cup butter: ~135 g

The catch: if you use a US 1/2-cup measure (120 ml) to follow a UK recipe, you’ll under-measure by about 18% — enough to shift a cake from moist to dry.

How do I measure half a cup in grams?

The most reliable method is to use a digital kitchen scale. But if you need to use volume measurements, technique matters — especially for dry ingredients.

Using a digital scale for precision

1. Set your scale to grams
2. Place an empty bowl on the scale and press “tare” to zero it
3. Add ingredient until you reach the desired gram weight
4. This eliminates all volume-related variability

The spoon-and-sweep method for dry ingredients

1. For flour: spoon it gently into the measuring cup, then level off with a straight edge (like the back of a knife)
2. For sugar: scoop directly from the bag, then level
3. For brown sugar: pack firmly into the cup, then level — the weight can vary by 10–20% depending on packing (King Arthur Baking (baking education resource))

Using a liquid measuring cup for wet ingredients

1. Use a clear glass or plastic measuring cup with spout
2. Place on a flat surface and pour to the 1/2-cup line
3. Read at eye level for accuracy
4. For water, milk, and most liquids, 1/2 cup ≈ 120 g

What this means: precision is achievable with either method, but only a scale guarantees repeatable results across ingredients.

Is 250g of flour 1 cup?

No. One cup of all-purpose flour weighs approximately 125 grams (King Arthur Baking (baking education resource)). That means 250 grams of all-purpose flour equals about 2 cups, not 1.

Flour density and type (all-purpose, bread, cake)

• All-purpose flour: ~125 g per cup
• Bread flour: ~130 g per cup (higher protein density)
• Cake flour: ~115 g per cup (lower protein, finer texture)
• Whole wheat flour: ~130 g per cup (denser particles)

Six types, one pattern: each flour’s protein content and particle size shifts its weight per cup. Cake flour is about 8% lighter per cup than bread flour.

Why 250g of flour equals about 2 cups

• Standard conversion: 1 cup all-purpose flour = 125 g
• Therefore 250 g = 2 cups
• This assumes spoon-and-sweep technique; direct scooping can raise weight to 150 g per cup

How to weigh flour correctly

1. Use a digital scale, tare a bowl, add flour until you hit your target grams
2. If using cups: spoon flour into the cup (do not scoop directly from the bag)
3. Level with a straight edge
4. Avoid shaking or tapping the cup, which settles flour and increases weight

The implication: always confirm the flour type and technique before converting volume to grams.

For additional ingredient-specific weights, see our detailed half-cup to gram conversions that include variations for flour, butter, and sugar.

Frequently asked questions

For consistent results, invest in a digital scale and use the conversions in this guide as your reference.