1 Cup to Grams: US & UK Conversion Charts and Guide

There’s a reason baking scales have become a kitchen staple. One cup of flour can weigh anywhere from 110 to 150 grams depending on how you scoop it, and Doves Farm (a UK flour brand) states that one cup of unsifted all-purpose flour weighs 120 grams — this guide breaks down exactly how much 1 cup of common ingredients weighs in grams, so you can bake with confidence.

1 US cup (water): 237 g ·
1 US cup (all-purpose flour): 125 g ·
1 US cup (granulated sugar): 200 g ·
1 US cup (butter): 227 g ·
1 UK cup (water): 284 g

Five key ingredient weights, one quick reference: the table below highlights the gram equivalents for the most commonly used baking ingredients, based on US legal cups (236.6 ml).

What is 1 cup in grams?

One US cup equals 236.6 ml, but the gram weight of a cup depends entirely on the ingredient’s density. For water, with a density of 1 g/ml, 1 US cup weighs about 237 g (Commercial Kitchen Store AU). For granulated sugar, the same cup holds 200 g (Anna Olson). Butter, being denser, comes in at 227 g per cup (Cotswold Flour).

The US legal cup definition (236.6 ml)

• The US legal cup is defined as 236.588 ml by the FDA (Wikipedia (standard reference)).
• Most US recipes written after 2000 use this size; older cookbooks may still refer to 240 ml.
• For everyday baking, the 3–4 ml difference is negligible.

Why the weight varies by ingredient

Density is the key. Flour particles trap air, so a cup of flour weighs only about 120–130 g, while a cup of honey (density ~1.4 g/ml) weighs around 340 g. Doves Farm notes that even the same ingredient can vary: unsifted flour (120 g) vs. sieved flour (110 g).

Is 250g equivalent to 1 cup?

Not generally. 250 grams is roughly 1.05 US cups of water, but it equals about 2 cups of all-purpose flour (Brownie Heaven). For granulated sugar, 250 g is about 1.25 cups (Cotswold Flour).

Density of common ingredients

• Water: 1 g/ml → 1 US cup ≈ 237 g
• All-purpose flour: ~0.5 g/ml → 1 US cup ≈ 125 g
• Granulated sugar: ~0.85 g/ml → 1 US cup ≈ 200 g
• Butter: ~0.96 g/ml → 1 US cup ≈ 227 g

When 250 g equals 1 cup

Only ingredients with a density close to 1.05 g/ml will give 250 g in 236.6 ml. Whole milk (1.03 g/ml) comes very close: 1 US cup ≈ 244 g. But for dry ingredients like flour, 250 g is far more than one cup.

Why 250 g of flour is more than 1 cup

Because flour is light: at 125 g per cup, 250 g equals two full cups. The English Kitchen notes that 1 lb (454 g) of flour equals about 4 cups, reinforcing the 125 g/cup average.

Is 1 cup of flour 100g?

Only if the flour is very aerated or sifted. Most professional sources in the US and UK give 120–125 g for unsifted all-purpose flour. Cotswold Flour says 1 cup unsifted = 120 g, sifted = 110 g. The 100 g figure sometimes appears in old Australian recipes or very loosely scooped cups.

Standard weight of all-purpose flour (120–125 g per cup)

• US legal cup: 125 g per King Arthur Baking.
• UK cup (284 ml): about 133 g (Brownie Heaven).
• Canadian baker Anna Olson uses 150 g per cup – a reminder that different standards exist.

Why some sources say 100 g (different flour types, scoop method)

Whole wheat or rye flours are slightly heavier (130–140 g per cup), while cake flour is lighter (~115 g). The scoop-and-level method packs more flour than spoon-and-level, adding 5–10 g.

How to measure flour correctly for accurate grams

Spoon the flour into the cup, then level with a knife. This gives the most consistent weight. Avoid dipping the cup into the bag — that can add 20% more flour (Serious Eats).

How much is 1 cup in the UK?

A UK cup is 284 ml — about 20% larger than a US cup. This difference has a significant impact on gram conversions. Doves Farm uses the US cup in its tables, but also notes that UK cups are sometimes labelled as 250 ml for simplicity.

UK cup = 284.1 ml (imperial)

This is the imperial cup, derived from the UK pint (568 ml). US and UK cups differ by about 20%.

UK cup for dry ingredients

• 1 UK cup all-purpose flour ≈ 133 g (Brownie Heaven).
• 1 UK cup granulated sugar ≈ 225 g (The English Kitchen).

How to convert between US and UK cup recipes

If you’re following a US recipe with a UK cup, multiply all US cup values by 1.2 (since 284/236.6 ≈ 1.2). For precise conversions, it’s easier to use gram weights directly.

Is 250 grams of dry ingredients like flour 1 or 2 cups?

For flour, 250 g is about 2 US cups (assuming 125 g/cup). For granulated sugar, 250 g is about 1.25 cups (Cotswold Flour). The key is always the ingredient’s density.

Why 250 g flour ≈ 2 cups

Flour density is ~0.5 g/ml. 250 g ÷ 125 g/cup = 2 cups. Doves Farm confirms that 1 cup of plain flour (unsifted) is 120 g, so 240 g would be 2 cups.

Why 250 g sugar ≈ 1.25 cups

Sugar density is ~0.85 g/ml. 250 g ÷ 200 g/cup = 1.25 cups. This is why a single cup measure for all dry ingredients is unreliable.

Rule of thumb: check ingredient density

Divide the mass (grams) by the grams-per-cup for that ingredient. If you don’t have a specific value, assume flour = 125 g/cup, sugar = 200 g/cup, butter = 227 g/cup, and liquids = 237 g/cup.

Three cup systems, one common pitfall: the table below shows how the same volume mark gives very different gram weights depending on the system used.

For quick reference, here are gram weights for 1 US cup of more than a dozen common baking ingredients.

How to convert cups to grams step by step

If you don’t have a conversion chart, you can calculate it manually. Here’s a simple process.

1. Identify the cup system: US (236.6 ml), UK (284 ml), or metric (250 ml). Look for clues in the recipe origin.
2. Look up the ingredient’s density (grams per millilitre) or its standard grams-per-cup from a reliable source like King Arthur Baking.
3. Multiply the number of cups by the grams-per-cup for that ingredient.
4. Round to the nearest gram – scales don’t need decimals.

For example: 2 US cups of granulated sugar = 2 × 200 g = 400 g. For ½ cup of butter = 0.5 × 227 g = 113.5 g (round to 113 g).

What we know and what’s still unclear

Confirmed facts

• 1 US cup = 236.6 ml (Wikipedia)
• 1 UK cup = 284.1 ml (Brownie Heaven)
• 1 US cup all-purpose flour = 120–125 g (Cotswold Flour)
• 1 US cup granulated sugar = 200 g (Anna Olson)
• 1 US cup butter = 227 g (Cotswold Flour)
• Liquids: 1 US cup = 237 g for water (Commercial Kitchen Store AU)

What’s unclear

• Exact weight of 1 cup of flour can vary by ±10 g depending on measuring technique (Cotswold Flour)
• Some recipes use a 250 ml metric cup that is not standardized in the US or UK (Commercial Kitchen Store AU)
• Different flour types (whole wheat, rye, gluten-free) have varying cup weights not always listed in standard tables
• Butter per cup ranges from 227g to 240g across sources
• US cup is sometimes rounded to 240ml, adding minor inconsistency
• Anna Olson uses 150g per cup for flour, a different standard

Expert perspectives

“Often used in US, a cup is 240ml or 8.45 imperial fluid ounces.”

— Doves Farm conversion table

“For water, 1 cup equals 240g. For all-purpose flour, 1 cup equals 125g. For granulated sugar, 1 cup equals 200g. For butter, 1 cup equals 227g.”

— Allrecipes conversion guide

For home bakers following US or UK recipes, the choice is simple: invest in a digital scale and use gram weights instead of cups. The error from misinterpreting cup size or ingredient density routinely adds 10–30% more or less of an ingredient, and that difference can turn a light cake into a brick. If you also work with pounds and kilograms, this converter table may come in handy. For bakers who want consistent results, a scale is the one tool that eliminates every cup-related ambiguity.

Related reading: 1 pound in kg converter table · Chocolate Fudge Cake Recipe

For bakers who need precise measurements, understanding 1 cup flour in grams is essential since flour weight can vary significantly depending on how it is scooped.

Frequently asked questions