Recipes come from all over the world in different measurement systems. This guide covers the conversions that matter, with context on when precision is critical and when approximate is fine.
Weight Conversions
Weight is the most reliable way to measure ingredients, particularly in baking where ratios matter significantly.
1 ounce (oz) = 28.35g | 1 pound (lb) = 453.6g
| Grams | Ounces/Pounds |
|---|---|
| 100g | ~3.5oz |
| 250g | ~9oz |
| 500g | ~1lb 2oz |
| 1kg | ~2lb 3oz |
Volume Conversions
This is where confusion is highest, as US, UK, and Australian measures are not identical.
| Unit | Metric Equivalent |
|---|---|
| US cup | 240ml |
| Australian/UK cup | 250ml |
| US pint | 473ml |
| UK pint | 568ml (~20% more than US) |
| 1 tablespoon | 15ml |
| 1 teaspoon | 5ml |
Oven Temperature Conversions
°C to °F: multiply by 9/5, then add 32
°F to °C: subtract 32, then multiply by 5/9
| Celsius | Fahrenheit | Use |
|---|---|---|
| 150°C | 300°F | Slow roasting, meringues |
| 180°C | 350°F | Standard cakes, biscuits |
| 200°C | 400°F | Roasting vegetables, meat |
| 220°C | 425°F | Pizza, bread |
Fan ovens cook more efficiently — reduce stated temperatures by 15-20°C (25-35°F) and check items earlier.
When Precision Matters
Baking is the area of cooking where measurement precision matters the most, by a clear margin. The ratio of flour, fat, sugar, and leavening agent determines the structure, texture, and rise of the finished product in a way that's much less forgiving than savoury cooking — too much flour produces a dense, dry cake, while too little can cause it to collapse during baking. Professional bakers weigh every ingredient, including liquids, specifically to achieve this kind of consistency batch after batch.
For savoury cooking — roasting, frying, braising, making soups and stews — precise measurement matters far less, and recipes are better understood as guides rather than exact formulas to be followed to the gram. Being 10-20% over or under on a given ingredient rarely makes a meaningful difference to the final result in these contexts, which is part of why experienced cooks often work by eye and taste rather than measuring everything precisely, while still weighing carefully whenever they bake.
Baking requires precise ratios of flour, fat, sugar, and leavening — weighing all ingredients including liquids gives consistent results. Savoury cooking (roasting, stews, soups) is far more forgiving — recipes function better as guides than precise formulas.
Common Conversion Mistakes
One of the most frequent errors when converting recipes is confusing weight and volume measurements for the same ingredient, particularly flour. A cup of flour and 125g of flour are not interchangeable terms — they're different ways of measuring the same ingredient, and the actual weight of "one cup" of flour varies depending on how densely it's packed into the cup, making weight-based measurement considerably more reliable for consistent baking results.
Another common mistake is assuming all liquid measuring cups and dry measuring cups are equivalent. US recipes typically distinguish between the two, since a liquid measuring cup with a pour spout is designed to be read at eye level with the liquid meniscus aligned to the marking, while dry measuring cups are designed to be levelled off with a straight edge for an accurate flat-top measurement. Using a dry measuring cup for liquids, or vice versa, introduces a small but real source of measurement error that becomes more significant the more precise the recipe demands.