To convert a recipe from cups to grams, multiply each ingredient's cup volume by that ingredient's own gram-per-cup weight — not a single universal number. One US cup is 236.588 mL, but it holds about 120 g of flour and 200 g of sugar. Work ingredient by ingredient, then weigh to confirm.
Below is the procedure, with a check after every step so you can catch a mistake before it reaches the oven.
Why can't you convert cups to grams with one number?
Because cups measure volume and grams measure mass. Flour is fluffy and full of air; honey is dense and packed. Pour each into the same 236.588 mL cup and you get roughly 120 g of one and 340 g of the other. The bridge between the two is density:
grams = cup volume in mL × density in g/mL
Water is the friendly case: 1 mL of water weighs almost exactly 1 g at room temperature, so a US cup of water is about 237 g. Everything else needs its own number — the same "which version of the unit is this?" trap covered in our guide to unit conversions and their gotchas.
Which cup is your recipe actually using?
There are three cups in common circulation, and they are not the same size:
| Cup type | Volume | Where you'll meet it |
|---|---|---|
| US customary cup | 236.5882365 mL (exact) | US recipe sites, US cookbooks |
| US legal cup | 240 mL (exact) | US nutrition labels |
| Metric cup | 250 mL (exact) | Australia, New Zealand, much of Europe |
A metric cup is about 5.7% larger than a US customary cup ((250 − 236.5882365) ÷ 236.5882365 = 0.0567). On one cup of flour that's roughly 7 g; on a four-cup bread recipe it's nearly 30 g — a visibly drier dough.
How do you convert a recipe from cups to grams, step by step?
Work through the recipe once, top to bottom. Each step has a check.
1. Identify the cup. US source, or °F and sticks of butter elsewhere in the method? Assume the US customary cup, 236.588 mL. Australian, NZ or European source, or metric temperatures? Assume the metric cup, 250 mL. Check: if the recipe lists millilitres anywhere ("1 cup / 250 mL"), it has told you outright — trust that over your guess.
2. Write the volume of one cup in millilitres at the top of your notes. You'll reuse it for every line. Check: the number you wrote is one of 236.588, 240 or 250 — never a rounded "235" or "245".
3. List every cup-measured ingredient on its own line. Convert fractions to decimals as you go: ½ = 0.5, ⅓ = 0.333, ¼ = 0.25, ⅔ = 0.667, ¾ = 0.75. Check: every line now reads as number × ingredient, with no mixed fractions left ("1½ cups" becomes "1.5 cups").
4. Look up each ingredient's weight per cup. Use the table below, or multiply the cup volume by the ingredient's density. Check: anything fluffy (flour, oats, cocoa) must come out lighter than a cup of water (237 g); anything syrupy (honey) must come out heavier.
| Ingredient | g per US cup (236.588 mL) | g per metric cup (250 mL) | Density (g/mL) |
|---|---|---|---|
| Water | 237 | 250 | 1.00 |
| All-purpose flour (spooned) | 120 | 127 | 0.51 |
| Granulated sugar | 200 | 211 | 0.85 |
| Brown sugar (packed) | 213 | 225 | 0.90 |
| Butter | 227 | 240 | 0.96 |
| Milk | 245 | 259 | 1.04 |
| Honey | 340 | 359 | 1.44 |
| Rolled oats | 90 | 95 | 0.38 |
| Cocoa powder | 85 | 90 | 0.36 |
Typical values, rounded to the nearest gram. Dry ingredients vary with packing — see the gotchas below.
5. Multiply each line. Cups × grams-per-cup = grams. For a US-cup recipe reading 2 cups flour, 1 cup granulated sugar, ½ cup butter, ¾ cup milk:
- Flour: 2 × 120 = 240 g
- Granulated sugar: 1 × 200 = 200 g
- Butter: 0.5 × 227 = 113.5 g
- Milk: 0.75 × 245 = 183.75 → 184 g
Check: the butter line is the built-in test. A US stick of butter is a quarter-pound: 0.25 × 453.59237 = 113.398 g, and half a cup is one stick. Our 113.5 g lands on it. If your butter maths doesn't produce roughly 113 g per half cup, something upstream is wrong.
6. Convert the small and odd measures. A US tablespoon is 1/16 cup = 14.7868 mL; a US teaspoon is 1/3 tablespoon = 4.9289 mL. A metric tablespoon is 15 mL — except in Australia, where it is 20 mL (4 teaspoons). Weight ounces convert exactly: 1 oz = 28.349523125 g, so 8 oz = 226.796 → 227 g. Check: for "8 oz" of a liquid, decide whether it means weight or fluid ounces. A US fluid ounce is 29.5735295625 mL, and 8 make exactly one US cup.
7. Convert the oven temperature — with the offset, not a factor. °C = (°F − 32) × 5/9, and °F = °C × 9/5 + 32. Worked: 350 °F → (350 − 32) × 5/9 = 318 × 5/9 = 176.67 °C, so set 175 °C (or 180 °C on a dial with 10-degree steps). Going the other way, 180 °C → 180 × 9/5 + 32 = 356 °F. Check: a difference in temperature never takes the +32. "Drop the oven by 20 °C" for a fan oven means dropping 36 °F (20 × 9/5), not 68 °F.
8. Round last, and round sensibly. Do the arithmetic at full precision, then round once at the end — nearest gram above 20 g, 0.1 g for yeast and salt if your scale reads that finely. "183.75 g of milk" is precision your measuring cup never had. The round-only-at-the-end rule and the odd behaviour of 0.5 cases are covered in our number systems and rounding guide. Check: no value has more decimal places than your scale can show.
9. Weigh the total as a final proof. Tare a bowl, add ingredients one at a time, and confirm the running total matches your paper sum. Our example totals 240 + 200 + 113.5 + 184 = 737.5 g before eggs. Check: if the bowl and the paper disagree by more than a couple of grams, one line was converted with the wrong cup or the wrong ingredient row.
One thing you should not convert: time. Doubling a batch does not double the bake. If a recipe needs proofing windows or overnight rests worked out across a clock change, that's date math, not unit math — see our date and time tools guide.
Where do cup-to-gram conversions go wrong?
Three failure modes account for nearly all of it.
Packing. A cup of flour scooped from the bag can weigh 140 g or more; the same cup spooned in and levelled is nearer 120 g. That's why the table above says "spooned". Brown sugar is the opposite: it's meant to be packed, and an unpacked cup underweighs badly.
Word order. "1 cup sifted flour" means sift, then measure. "1 cup flour, sifted" means measure, then sift. The first is noticeably lighter — the comma is load-bearing.
Assuming the wrong cup. The 5.7% gap is invisible in a cookie recipe and fatal in a bread hydration. When a recipe gives no clue, look at the temperatures: °F implies a US cup, °C implies a metric one.
For the wider set of small conversions that interrupt a normal week, our everyday conversion toolkit collects them with worked examples.
FAQ
How many grams is 1 cup of flour?
About 120 g for a US customary cup of spooned-and-levelled all-purpose flour, or about 127 g for a metric 250 mL cup. Scooped straight from the bag it can reach 140 g, so weighing beats converting.
Is 1 cup always 240 mL?
No. 240 mL is the US legal cup used on nutrition labels. The US customary cup used in recipes is 236.5882365 mL, and the metric cup used in Australia, New Zealand and much of Europe is 250 mL. The three differ by up to about 6%.
Can I use one conversion factor for the whole recipe?
Only if every ingredient has the same density, which in practice means water-like liquids only. Flour, sugar, butter and honey each need their own number.
How do I convert cups of butter to grams?
A US cup of butter is 227 g, a half cup is one stick at 113 g, and a tablespoon is about 14 g. These come from the pound: a stick is a quarter of a pound, and 0.25 × 453.59237 = 113.398 g exactly.
What temperature should I use if the recipe is in Fahrenheit?
Apply °C = (°F − 32) × 5/9 and round to your dial. 350 °F is 176.67 °C (set 175 or 180), 375 °F is 190.56 °C (set 190), and 425 °F is 218.33 °C (set 220). For a fan oven, drop the Celsius figure by about 20 °C.
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