Unit & Temperature Converter

📏 Which cup? There is more than one

This is the single most common source of silent error in recipe conversion, and it is not a rounding argument — the definitions genuinely differ. The US customary cup is a sixteenth of a gallon, which works out at 236.588 mL. But 21 CFR 101.9 declares that for nutrition-labeling purposes a cup means 240 mL, a tablespoon 15 mL and a teaspoon 5 mL, all exactly. And the metric cup used across much of the world, including Australian recipes, is 250 mL. That is a spread of 1.4% between the two American definitions and 5.7% between the American customary cup and the metric one.

NIST is refreshingly candid about the smaller units. Handbook 44 calls the tablespoon and teaspoon imprecise units outright, and lists their metric equivalents rounded to the nearest millilitre — 15 and 5 — while separately defining the tablespoon as exactly half a fluid ounce, which is 14.787 mL. Both statements sit in the same table. For seasoning, none of this matters. For baker's percentages, a 5.7% error on the liquid is the difference between a dough and a batter.

⚖️ This converts units, not ingredients

The volume and weight tabs above do not talk to each other, and that is deliberate. Converting cups to grams requires knowing the density of the specific thing in the cup, and for most cooking ingredients there is no single correct figure. USDA FoodData Central gives a cup of all-purpose white flour as 125 g. King Arthur Baking's ingredient weight chart gives 120 g. Neither is wrong; they reflect different assumptions about how the cup was filled, and a scooped-and-packed cup of flour can weigh substantially more than a spooned-and-levelled one.

If a recipe gives weights, use weights. It is the reason serious baking recipes moved to grams, and no converter can recover the precision that measuring flour by volume threw away.

🌡️ Oven dials do not line up

Fahrenheit and Celsius ovens are both marked in round numbers, but the round numbers are not the same temperatures. 180 °C is 356 °F, not 350. 200 °C is 392 °F, not 400. 220 °C is 428 °F, not 425. The differences are small enough to ignore for most baking and large enough to notice on something temperamental, and they are dwarfed by how far a domestic oven drifts from its own setting — which is why an oven thermometer tells you more than either conversion does.

🔒 Where rounding stops being harmless

Everywhere on this page except one place, rounding is cosmetic. The exception is a safe minimum internal temperature, where the number is a floor rather than an estimate. 165 °F is 73.9 °C; round that to 74 °C and you are fine, because 74 °C is 165.2 °F. Round it down to 73 °C and you are at 163.4 °F, which is below the target. Round food-safety temperatures up, never down, and treat the converter as a reading aid rather than as the authority — a calibrated thermometer in the thickest part of the food is the only thing that establishes doneness. The USDA figures are on our safe internal temperature reference.

❓ Common questions

Is 1 cup the same as 250 ml?

Only if the recipe is metric. There are three cups in common use and they are genuinely different sizes. The US customary cup, which is what this converter uses, is one sixteenth of a US gallon and comes to 236.588 ml. The US nutrition-labeling cup is defined by regulation as exactly 240 ml, under 21 CFR 101.9, which is also why a teaspoon on a nutrition panel means exactly 5 ml and a tablespoon exactly 15 ml. The metric cup used in Australia and much of Europe is 250 ml. So a metric cup is about 5.7% larger than a US customary one. For seasoning that gap is invisible; for bread dough, cake batter or anything where the liquid-to-flour ratio decides the outcome, it is worth knowing which cup the recipe author was holding.

Is 180 C the same as 350 F oven?

Not exactly, though they are treated as equivalents because both are the standard moderate setting on their own dials. 180°C is 356°F, so a recipe converted from 180°C to 350°F runs about 6°F cool. In the other direction 350°F is 176.7°C, which no European oven dial offers. For most baking the 6°F is immaterial, and it is smaller than the error in a typical domestic oven anyway — ovens routinely run tens of degrees away from their setting, and an oven thermometer will tell you more about yours than any conversion will. Where it does matter, in sugar work or delicate custards, set the temperature you actually want rather than the nearest round number and verify it with a thermometer in the oven.

What temperature is 220 C to F in the oven?

220°C is 428°F. The nearest common Fahrenheit dial setting is 425°F, which is 218.3°C, so treating them as the same runs about 3°F cool — the closest of the usual pairings and safely ignorable for roasting and bread. The pairings people use are 160°C to 325°F, 180°C to 350°F, 200°C to 400°F and 220°C to 425°F, and none of them are exact. If you want the arithmetic rather than the convention, the conversion is °F = (°C × 9/5) + 32. One caution: this applies to oven air temperature, which is a setting, not to the internal temperature of food, which is a food-safety threshold and should be rounded up rather than approximated.

What is 1 cup in grams?

There is no answer without knowing what is in the cup. A cup is a volume and a gram is a mass, so the conversion depends entirely on the density of the ingredient, and this converter deliberately keeps its volume and weight tabs separate for that reason. Water is the easy case, at very close to 237 g per US customary cup. Flour is the instructive one: USDA FoodData Central gives a cup of all-purpose white flour as 125 g, while King Arthur Baking's ingredient weight chart gives 120 g, and a cup that has been scooped straight from the bag and packed down can weigh appreciably more than either. Neither source is wrong — they assume different filling methods. If a recipe offers gram weights, use them, because that precision cannot be reconstructed from a cup measurement after the fact.

The exact definitions behind every factor on this page — 1 inch = 2.54 cm, 1 gallon = 231 cubic inches, 1 cup = 8 fluid ounces, 1 tablespoon = 3 teaspoons = ½ fluid ounce, 1 pound = 453.59237 g, 1 ounce = 28.349523125 g, and the description of the tablespoon and teaspoon as imprecise units — are from NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement. The 240 mL cup, 15 mL tablespoon and 5 mL teaspoon used on nutrition labels are defined at 21 CFR 101.9(b)(5)(viii). Flour weights are from USDA FoodData Central (125 g per cup) and the King Arthur Baking ingredient weight chart (120 g). Safe internal temperatures are from the USDA FSIS Safe Minimum Internal Temperature Chart.