Cooking Unit Converter

What do I need to know about Volume?

Volume measurements vary surprisingly between countries, and the 'same' measurement can differ by 20% depending on which cup or spoon convention a recipe uses. The standard equivalences: 1 US cup = 240 ml; 1 UK cup = 284 ml (about 18% larger than US); 1 metric cup = 250 ml. 1 tablespoon = 15 ml in UK, US, and Canada, but an Australian tablespoon is 20 ml — noticeably bigger. 1 teaspoon = 5 ml in all systems (this is the most consistent). 1 fl oz (UK) = 28.41 ml; 1 fl oz (US) = 29.57 ml. The differences are small per unit but compound across a recipe with multiple measurements — a UK 'cup' of flour is meaningfully more than a US cup. The practical rule: when following an American recipe, use US cup measurements (or convert to grams via weight conversions, which is more reliable still); for a UK recipe in cups, use UK cup measurements. For maximum accuracy in baking especially, ignore cup measurements altogether and use a digital scale (grams or ounces). Sticky ingredients like honey, syrup, or molasses are easier to weigh than to scoop and scrape from a measuring cup, and you'll lose far less. Always specify which standard a recipe uses if you're sharing it. This calculator handles the various conventions and lets you convert cleanly between them.

What's the key thing to understand about Weight?

Weight measurements are more universal than volume, but conversions between metric and imperial still trip people up. The standard equivalences: 1 oz = 28.35 g; 1 lb = 453.6 g; 1 kg = 2.205 lb; 1 stone = 6.35 kg (used in UK for body weight, almost never in cooking). For practical cooking, useful round figures: 100 g ≈ 3.5 oz; 250 g ≈ 9 oz; 500 g ≈ 1 lb 2 oz; 1 kg ≈ 2 lb 3 oz. For baking specifically, weight is always more accurate than volume — flour in particular can vary by 20% or more between a tightly-packed cup and a loosely-spooned cup, depending on how you fill the measure, and this translates directly into different doughs and batters. A digital kitchen scale (cheap and readily available) eliminates this variability and is the single most useful tool for consistent baking. Most modern recipes are written in grams in the UK, but older or imported recipes use ounces, and converting takes care to avoid compounding errors across an ingredient list. For very small quantities (under 10 g), even decent scales become imprecise; teaspoon measurements are often better for tiny amounts like spices, salt, or yeast. This calculator handles the conversions between common weight units; for accuracy in baking, a scale beats any volume conversion.

What's the key thing to understand about Oven Temperature?

Three different oven temperature scales coexist in cookery — Celsius (the metric standard), Fahrenheit (US standard), and gas marks (a UK-specific system) — and recipes from different sources use different scales, which means converting them is a daily need. Key reference points: gas mark ¼ = 110°C = 225°F (very cool, used for slow cooking and dehydrating); gas mark 1 = 140°C = 275°F (low oven, for braising or warming through); gas mark 4 = 180°C = 350°F (moderate, the most common 'roast' temperature); gas mark 6 = 200°C = 400°F (hot, for pastry and crisp roasting); gas mark 7 = 220°C = 425°F (very hot, for searing roasts and bread); gas mark 9 = 240°C = 475°F (very hot, for pizza and bread crust). The Celsius–Fahrenheit conversion is F = C × 9/5 + 32, and reverse C = (F − 32) × 5/9, but in practice it's faster to remember the reference points than to do the arithmetic each time. Fan (convection) ovens cook faster and more evenly than conventional ovens because the moving air transfers heat more efficiently to the food's surface — the standard advice is to reduce the recipe temperature by 15–20°C for fan ovens, or keep the temperature the same and reduce the time by 10–15%. Many newer recipes specify both conventional and fan temperatures (e.g. '180°C / 160°C fan / gas 4'), removing the guesswork. This calculator handles all three scales and the fan adjustment.

What's the key thing to understand about Food Safety Fundamentals?

Food safety rules apply regardless of cooking method or time. The danger zone for bacterial growth is 4-60 degrees C — food should not remain in this range for more than 2 hours. Core temperature targets: poultry 75 degrees C throughout (no pink allowed), pork 75 degrees C, beef/lamb can be pink when above 63 degrees C (due to surface-only bacteria on whole cuts). Never use the same equipment for raw and cooked food without washing. Leftovers should be cooled rapidly (within 2 hours), refrigerated promptly, and used within 3-4 days, or frozen for longer storage. When reheating, food should reach 75 degrees C throughout, and should only be reheated once.

What should I know about Converting Between Metric and Imperial Spoon Measures?

Spoon measures are a common source of small but meaningful conversion errors, partly because the actual volume of a 'tablespoon' or 'teaspoon' varies slightly between measuring systems. A standard metric tablespoon is 15ml and a metric teaspoon is 5ml, which is the convention used in UK, Australian, and most international recipes, and these are the figures used by standard measuring spoon sets sold in the UK. US recipes use a very slightly smaller tablespoon (around 14.8ml) and teaspoon (around 4.9ml) — close enough to the metric figures that the difference is negligible for most cooking, though it can matter in very precision-dependent recipes like baking or cocktail-making where ratios are tightly specified. More significant than the metric/US spoon size difference is the difference between a 'level' and a 'rounded' or 'heaped' spoon measure, which isn't standardised at all and depends entirely on how a cook interprets the instruction — a heaped teaspoon of a dense ingredient like baking powder can easily contain 50% more than a level teaspoon, enough to visibly affect a bake's rise. Where a recipe doesn't specify, assuming a level spoon measure is the safer default, since most published recipes default to level measures unless 'heaped' or 'rounded' is explicitly stated.

Reference: Common US-to-Metric Baking Conversions

Recipe conversion errors cluster around a handful of commonly mismeasured ingredients, mostly because volume-to-weight conversion for dry ingredients depends on how densely the ingredient is packed into the cup.

Flour is the biggest risk: a packed cup of flour can weigh 140g or more versus a properly spooned-and-levelled cup at 120-125g, a difference large enough to noticeably stiffen a cake or bread dough if the recipe assumes the lighter spooned measure, which most published US recipes do.

Worked Example: Converting a US Recipe to Metric

A US recipe calls for 2¼ cups of all-purpose flour, 1 cup of granulated sugar, ½ cup of butter, and an oven temperature of 375°F. Flour: 2.25 cups x 122g/cup (spooned average) ≈ 275g. Sugar: 1 cup x 200g = 200g. Butter: 0.5 cups x 227g = 113.5g, rounded to 114g. Oven temperature: 375°F converts using (°F − 32) ÷ 1.8 = (375 − 32) ÷ 1.8 = 343 ÷ 1.8 ≈ 190.6°C, rounded to the nearest standard oven setting of 190°C (or gas mark 5). The converted recipe: 275g flour, 200g sugar, 114g butter, baked at 190°C — weighing these on a digital kitchen scale gives a far more repeatable result than measuring the equivalent volumes with UK cup or spoon measures, which are not standardised to the same sizes as US cups.

What should I know about Liquid vs Dry Measuring Cups?

US recipes distinguish between liquid measuring cups (marked with a pour spout, read at eye level) and dry measuring cups (filled level to the rim and swept flat with a knife edge), and the two are not perfectly interchangeable for accuracy even though both claim to measure the same 240ml cup. A dry ingredient scooped into a liquid measuring cup is prone to being under- or over-filled since there is no flat rim to level it against, which is another reason weighing ingredients on a digital scale avoids an error that cup-based conversion alone cannot fully solve.