Why oven temperatures are a language problem
British recipes use gas mark. American recipes use Fahrenheit. European recipes use Celsius. The same roast chicken turns up at "400°F" in a New York Times recipe, "200°C" in a Guardian recipe, and "gas mark 6" in an old Delia Smith cookbook — and yes, those are all the same temperature. The chart above cross-references them so you never need to do the math with oven mitts on.
A few temperature zones do 90% of the work. Moderate (175°C / 350°F / gas 4) is the default for cakes and casseroles. Hot (200°C / 400°F / gas 6) is the default for roast chicken and vegetables. Very hot (230°C / 450°F / gas 8) is pizza and artisan bread territory. Everything else is a variation.
How to convert °C to °F and back (without a phone)
The formula is F = C × 9/5 + 32. That's hard to do with flour on your hands. Two kitchen shortcuts:
- Double and add 30. 160°C → ~350°F (real 320 — this is one of the cases where the shortcut breaks at high temperatures). For 150°C and below the shortcut holds; above, it drifts.
- Memorize five landmarks. 120°C = 250°F. 150°C = 300°F. 175°C = 350°F. 200°C = 400°F. 230°C = 450°F. Every other recipe temperature slots between those.
Convection (fan) and why recipes don't usually warn you
About 60% of US ovens sold since 2015 have a convection mode. Many users leave it on by default because things cook faster and browner. The catch: recipes rarely specify whether they assume convection or conventional. The rule of thumb is:
- Convection on: reduce temperature by 20°C / 36°F, or reduce time by 20%.
- Convection off: follow recipe as written.
- Pizza, bread, roast meat: convection usually helps; keep the temperature, shorten the time.
- Custards, soufflés, delicate cakes: turn convection off; the moving air dries the surface too fast.
Safe internal temperatures — what the USDA actually says
The USDA publishes two sets of guidance: "instant-kill" temperatures (high enough that no hold time is needed) and pasteurization curves (lower temperatures held for longer). Home cooks usually follow the instant-kill numbers because they're simpler. Professional sous-vide cooks use the curves because they produce better texture.
- Poultry: 74°C / 165°F instant-kill. Or 65°C / 150°F held for 3 min (pasteurized).
- Ground meat: 71°C / 160°F (grinding spreads surface bacteria).
- Whole cuts of pork: 63°C / 145°F + 3 min rest.
- Whole cuts of beef: 63°C / 145°F is medium. Rare/medium-rare is at your discretion.
- Fish: 63°C / 145°F. Many chefs pull earlier.
- Eggs: 71°C / 160°F to kill salmonella. Raw-yolk dishes (Caesar, aioli) use pasteurized eggs.
Reading an oven thermometer honestly
The temperature sensor inside most home ovens is mounted on the back wall, not the center of the cavity. It measures what the oven thinks the air is, which may differ from what your baking sheet in the middle feels. A $15 stainless oven thermometer placed next to the food tells you the truth. If it reads 335°F when the dial says 350°F, write "+15" on a sticky note on the oven and mentally add that to every recipe.
Altitude adjustments
Above 3,000 ft (1,000 m), water boils at a lower temperature and leavening gases expand more. Typical adjustments:
- Cakes & quick breads: increase oven temp by 15°F / 8°C and reduce baking time by 5–8 minutes.
- Baking soda/powder: reduce by ¼ tsp per tsp called for.
- Sugar: reduce by 1–2 tablespoons per cup (slows rise).
- Liquids: add 1–2 tbsp per cup to compensate for faster evaporation.
Related tools
- Temperature converter — exact Celsius / Fahrenheit / Kelvin.
- Temperature by feel — where cooking temps sit among other references.
- Cooking reference card — ingredient weights.
- Cooking volume converter — cups, tbsp, ml.
- Cooking weight converter — grams, ounces, pounds.