Temperature Converters

Temperature Conversions: A Practical Guide

Australia uses Celsius. The US uses Fahrenheit. Scientists use Kelvin. Your oven might use gas marks. And the recipe you're following from an American cooking blog says "bake at 350 degrees" without specifying which scale. Getting temperature conversions wrong in the kitchen is the difference between a golden roast chicken and a charred brick.

Weather and everyday temperature

Australians think in Celsius instinctively. A hot summer day is 35 degrees. A cold winter morning in Melbourne is 5 degrees. If you're checking weather from an American source, they'll use Fahrenheit. 95°F sounds alarming, but it's just 35°C. 32°F sounds cold, and it is: that's freezing point (0°C).

Two anchors worth memorising: room temperature is about 20 to 22°C (68 to 72°F). Body temperature is 37°C (98.6°F). With those two reference points, you can estimate most everyday temperatures without pulling up a converter.

Cooking: Celsius, Fahrenheit, and gas marks

This is where temperature conversions actually matter. An American recipe says "bake at 350 degrees." If your Australian oven is set to Celsius and you dial in 350, you'll destroy whatever you're cooking. 350°F is about 177°C. That's nearly double the intended temperature.

Most Australian ovens display Celsius. Imported American appliances sometimes default to Fahrenheit. If you've just moved into a place with an unfamiliar oven, check which scale it uses before you cook anything ambitious. The common baking temperatures to memorise: 160°C (320°F) for slow baking, 180°C (356°F) for standard, 200°C (392°F) for hot, 220°C (428°F) for very hot. Those four cover 90 percent of recipes.

Gas marks appear in older recipes, particularly British and vintage Australian cookbooks. Gas mark 4 is about 177°C (350°F). Gas mark 6 is about 204°C (400°F). If you're cooking from your grandmother's recipe cards, you'll probably need to convert gas marks to Celsius. We've added gas marks as a converter option above for exactly this reason.

Convection vs fan-forced ovens

This trips up more home cooks than Celsius vs Fahrenheit. If a recipe gives a conventional oven temperature, and your oven is fan-forced (which most modern Australian ovens are), you need to reduce the temperature by about 20°C. Fan-forced ovens circulate hot air, so they cook more evenly and effectively at a lower temperature.

A recipe that says 180°C conventional should be set to 160°C fan-forced. A recipe at 200°C conventional becomes 180°C fan-forced. This 20°C reduction is a general rule. Some ovens run hotter or cooler than their dial suggests. If you find things consistently burning or underdone, get an oven thermometer (about $15 from Kmart or Big W). It's the single cheapest upgrade you can make in a kitchen.

American recipes almost never specify fan-forced vs conventional because fan-forced ovens are less common in US kitchens. So when you convert a US recipe from Fahrenheit to Celsius, you might also need to drop another 20°C if your oven is fan-forced. That's two conversions: Fahrenheit to Celsius, then conventional to fan-forced.

Kelvin: when you need it

Kelvin is the scientific standard. It starts at absolute zero (the coldest temperature physically possible). Water freezes at 273.15 K and boils at 373.15 K. Room temperature is about 293 K. The conversion is simple: Kelvin = Celsius + 273.15. You'll encounter Kelvin in physics, chemistry, and engineering specifications. For everyday life, you can safely ignore it.

Common mistakes

The most dangerous mistake is setting your oven to the wrong scale. 350°C is roughly double 350°F. Your smoke alarm will tell you about the error before your timer does. Always check whether a recipe uses Celsius or Fahrenheit before preheating.

The other common mistake: assuming temperature scales are proportional. The difference between 10°C and 20°C (10 degrees) feels mild. The difference between 10°F and 20°F is only about 5.5°C, which is much less. Fahrenheit degrees are smaller than Celsius degrees, so a "10 degree" change means different things in each system.