How to Convert Recipe Measurements (Cups, Grams, °F, °C)

Half the recipes worth cooking are written in the “wrong” units for your kitchen — grams when you own cups, Fahrenheit when your oven speaks Celsius, milliliters when you have a measuring jug in ounces. Getting the conversion wrong is how a cake becomes a puddle, so here's the plain-English version.

The conversions that matter most

• Temperature: °C = (°F − 32) × 5 ÷ 9. As anchors: 350°F ≈ 175°C, 400°F ≈ 200°C, 425°F ≈ 220°C.
• Volume: 1 US cup ≈ 240 ml; 1 tablespoon ≈ 15 ml; 1 teaspoon ≈ 5 ml.
• Weight: 1 ounce ≈ 28 g; 1 pound ≈ 454 g.

The trap: weight vs. volume

The reason baking conversions go wrong is that a cup is a measure of volume but grams measure weight, and different ingredients weigh different amounts per cup. A cup of flour is about 120–125 g; a cup of granulated sugar is about 200 g; a cup of water is about 240 g. There is no single “cup to grams” number — it depends on the ingredient. This is why good conversion is ingredient-aware, not just arithmetic.

Scaling servings

Doubling a recipe isn't always linear — pan sizes, cook times, and seasoning don't all scale one-to-one — but for ingredient quantities, multiply by (desired servings ÷ original servings). A tool that scales the numbers for you removes the mental math and the mistakes.

Where iwant2eat fits

iwant2eat converts any stored recipe between original, metric, and imperial units — including oven temperatures — and scales quantities to the number of servings you want. You save a recipe once, in whatever units it came in, and read it in whatever units your kitchen uses. No printouts of conversion charts taped to the cupboard.