How-to

Cups to grams and °F to °C — how to convert a whole recipe

Published August 25, 2026 Last checked August 25, 2026

Why “1 cup = X grams” is the wrong question

A cup measures volume — how much space something takes up. A gram measures mass — how much something weighs. The number that connects them depends entirely on what you’re measuring and how it got into the cup. A cup of flour weighs about 120 grams. A cup of honey weighs about 340 grams. Same cup, wildly different numbers, because flour is full of air pockets and honey isn’t.

This is why a generic “cups to grams” calculator that spits back one universal number is guessing. It either assumes water (1 cup ≈ 236g) or silently assumes flour and gets sugar wrong. A useful converter has to be ingredient-aware — and so does a person converting a recipe by hand.

Cup-to-gram weights for common baking ingredients

These are US cup (236–240ml) weights, verified against King Arthur Baking’s ingredient weight chart where the ingredient appears there, spooned into the cup and leveled off (not scooped and packed) unless noted.

Flour is the one to watch. The same “1 cup” can weigh anywhere from about 120g to 150g depending on whether you spoon flour into the cup and level it, or scoop straight into the bag and pack it down — a 20 to 30 gram swing on a single cup, before anything else about the recipe changes. If a recipe doesn’t say which method it used, assume spoon-and-level; that’s what most published gram weights, including King Arthur’s, are built on.

Oven temperature: °F to °C, and to fan

The formula is °C = (°F − 32) × 5⁄9. What real recipes print is not that formula’s exact output — it’s a rounded, kitchen-usable number. 350°F is not 176.67°C, it’s 175°C or 180°C depending on which side of the Atlantic wrote the recipe. Both are correct in practice; ovens don’t hold temperature to a fraction of a degree anyway.

The fan column follows the common rule of thumb — cut about 20°C (roughly 25°F) off the conventional setting, because a fan oven circulates heat and cooks faster and more evenly than a conventional one. Some ovens print this adjustment right on the dial; if yours does, trust the dial over any chart, including this one.

Spoons, small volumes, and the tablespoon that isn’t

A US tablespoon and a UK tablespoon are both 15ml, close enough that the difference (14.79ml vs 15ml) never matters. An Australian tablespoon is 20ml — a third larger. That’s not a rounding error: substitute an Australian tablespoon for a US one across a recipe with several tablespoon measures and every one of them runs about 33% over. Teaspoons are the one constant — 5ml everywhere.

Cups have their own regional split. A US cup is 236.6ml, rounded to 240ml in most recipe contexts. The metric cup used in Australia, New Zealand, Canada, and most modern UK recipes is 250ml, about 4% bigger. Older British cookbooks sometimes use the legacy imperial cup, 284ml — a genuinely different measure, worth flagging on a vintage recipe. If a recipe doesn’t say which cup it means, assume US for American sites and 250ml metric for everything else written after roughly 1970.

What actually matters when you convert

Convert to weight, not volume, when baking. A scale removes the packing-and-leveling problem entirely — 120g of flour is 120g of flour no matter how it got into the bowl. If you bake more than occasionally and cook in metric, a scale is the single highest-leverage purchase you can make; it’s cheaper than the ingredients it saves you from wasting.

Round to numbers you can actually use. 176.67°C isn’t a real oven setting, and 84.6g of butter isn’t a real scale reading. Converted numbers should land on the nearest 5°C, the nearest gram or two — something a person can dial in.

Know where rounding matters and where it doesn’t. Yeast, salt, and baking powder or soda are load-bearing in small quantities — shift a teaspoon of baking soda by 20% and a cake rises differently. Vegetables and most fruit don’t care; “about 300g of onion” and “285g of onion” cook the same.

Watch the traps that aren’t really conversion problems:

• “1 stick of butter” is a US-only unit — 113g, half a cup, 8 tablespoons. Convert the stick first.
• “1 large egg” is a size grade, not a weight, but it’s commonly treated as 50g out of the shell (about 57g in shell) when a recipe needs scaling by egg weight rather than count. That 50g figure is also what makes “half an egg” possible when you’re scaling a recipe up or down — beat one and weigh out 25g.
• Fluid ounces and ounces share a name but measure different things — volume versus weight. They’re only interchangeable for something that weighs what water weighs, which butter, flour, and honey do not. “8 fl oz of milk” and “8 oz of flour” aren’t parallel measurements.

Converting a whole imported recipe with Sous Chef

Say you’ve pasted or imported a US recipe into Sous Chef and you cook in metric. Hand-converting it means going line by line — flour, sugar, butter, milk, the oven temperature, maybe a tablespoon buried in the method — and it only takes missing one line (the oven temp is the usual casualty) to end up with a recipe that’s half-converted and wrong in a way that’s hard to spot mid-bake.

In Sous Chef, switching units is a display setting on the working session, not eleven separate edits. You say “convert this to metric” and the whole recipe — every ingredient line and the oven temperature — flips at once, using the same conversion basis throughout, so nothing is left in cups while everything else moved to grams. A separate tweak, like “I only have salted butter,” goes through as a normal edit on top, with the changed line marked so you can see what moved.

Honest limits

Converted numbers are cooking numbers, not laboratory numbers. Weighing removes the packing-and-scooping error, but not every source of variation — flour absorbs liquid differently by humidity and brand, ovens run hot or cold by 10–15°C even when the dial says otherwise, and “1 cup of chopped walnuts” varies with chop size no matter which gram figure you use. A converted recipe still needs a cook’s judgment on doneness and texture; the conversion gets you a sane starting point, not a guarantee.

Common questions

Is there one universal “cups to grams” number I can memorize?

No. Any chart or app that gives you one number for all ingredients is assuming water or assuming flour. Flour, sugar, butter, and honey weigh differently by cup because they pack differently — you need a per-ingredient figure.

Why do American and British ovens list different Celsius numbers for the same recipe?

Both are rounding the same formula, °C = (°F − 32) × 5⁄9, to a number you can actually set. 350°F converts exactly to 176.67°C, which nobody’s oven displays, so recipes round to 175°C or 180°C depending on convention. Either is fine; the exact math was never the point.

Do I need to adjust time as well as temperature for a fan oven?

Usually just the temperature — drop it about 20°C (roughly 25°F) and keep the time as written, checking a few minutes early the first time. Don’t cut both at once; that tends to leave things underbaked.

Is a US tablespoon the same as a UK tablespoon?

Close enough in practice — 14.79ml versus 15ml. Watch Australia instead, where a tablespoon is 20ml, a third bigger. That difference compounds across a recipe with several tablespoon measures.

Should I convert by weight or just use a volume converter?

Weight, for baking. Volume conversions inherit every packing and leveling inconsistency from how the cup was filled; a gram of flour is a gram of flour regardless. For chopped vegetables or liquids added to taste, volume is fine.

Can Sous Chef convert just one ingredient instead of the whole recipe?

Units convert at the recipe level, which is what keeps a recipe from ending up half in cups and half in grams. Changing a single ingredient for a different reason, like swapping it out, is a normal edit request instead.