Convert oven temperatures and cooking temps from Fahrenheit to Celsius (and back).
Celsius = (Fahrenheit − 32) × 5/9. Fahrenheit = (Celsius × 9/5) + 32. Common cooking temps: 350°F = 177°C. 400°F = 204°C. 450°F = 232°C.
Gas mark 1 = 140°C = 275°F. Gas mark 4 = 180°C = 350°F. Gas mark 6 = 200°C = 400°F. Gas mark 9 = 240°C = 475°F.
Chicken/poultry: 165°F/74°C. Ground meat: 160°F/71°C. Whole beef/pork (medium rare): 145°F/63°C. Fish: 145°F/63°C. Leftovers: 165°F/74°C. Always use a meat thermometer.
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Older gas ovens used numbered dials instead of temperatures. Still common in older UK cookbooks and some gas ovens today.
Rough approximation: subtract 30 and halve (F → C). 350F → 320 → 160. Actual is 177 — close enough for most cooking.
Yes — reduce recipe temp by 25°F (15°C) when using convection. Time is often 20–25% shorter too.
USDA: 165°F (74°C) for poultry. 160°F (71°C) for ground meat. 145°F (63°C) for whole cuts + 3-min rest for beef/pork/fish.
Most home ovens are off by 10–25°F. Buy an inexpensive oven thermometer ($8) to verify. Many bake unevenly too — rotate pans halfway through.
Celsius to Fahrenheit: °F = (°C × 9/5) + 32. Fahrenheit to Celsius: °C = (°F − 32) × 5/9. Memorize one; the other inverts. For quick mental math, the rough approximations: (°C × 2) + 30 gets you within 5°F. (°F − 30) / 2 gets you within 3°C. These are fine for setting oven temps but fail for baking precision.
The four reference points every cook should know: water freezes at 0°C / 32°F. Water boils at 100°C / 212°F. Human body is 37°C / 98.6°F. A hot home oven for roasting is 200°C / 400°F.
These are not oven temperatures. These are internal meat temperatures measured with an instant-read thermometer (ThermoWorks Thermapen is the gold standard, $99; Lavatools Javelin Pro is $35 and 95% as good).
Older British cookbooks use "gas mark" for oven temps — a relic from town gas ovens. Mark 1 = 275°F / 135°C. Each mark adds 25°F / 14°C. Mark 4 = 350°F / 175°C (standard bake). Mark 7 = 425°F / 218°C. Mark 9 = 475°F / 246°C. French recipes often list only Celsius. German recipes distinguish "Umluft" (convection, typically 20°C lower than listed) from "Ober/Unterhitze" (top/bottom heat).
Home ovens are factory-calibrated within ±25°F, which is ridiculous for baking. A $10 oven thermometer (OXO, CDN) in the middle rack reveals the truth. Most ovens run 15-30°F below their set temperature. Some cycle — the element turns off and on, so the real temperature oscillates ±40°F around the set point. This is why the same cookie recipe bakes in 10 minutes at your house and 14 at your friend's.
The professional fix: calibrate. Set oven to 350°F. After 30 min preheat, read the thermometer. If it shows 330°F, your oven runs 20° cold; adjust by baking at 370°F when a recipe calls for 350°F. Many ovens have a calibration offset in the menu (check the manual — it's under "oven options" or "settings").
Convection ovens circulate air with a fan, cooking 20% faster and browning more aggressively. Rule of thumb: reduce convection temperature by 25°F / 15°C from the recipe, OR reduce cook time by 25%. Not both. Modern convection (called "true convection" or "European convection") has a heating element around the fan and is more efficient than old-style "convection" that just adds a fan to a regular oven.
Sous vide lets you cook at the exact internal temperature of the food — no carryover, no overshoot. Steak at 132°F (55.5°C) for 2 hours: perfect medium-rare edge to edge. Chicken breast at 150°F (65.5°C) for 90 minutes: safe, juicy, impossible to overcook. Egg yolk structural transitions happen at 145°F, 158°F, 167°F; sous vide eggs at 64°C (147°F) give you "onsen eggs" with softly-set whites and still-runny yolks.
Related: cooking time by weight, turkey cooking calculator, pressure cooker time, slow cooker conversion.
An instant-read thermometer is the single most transformative tool in any kitchen. Not for converting F to C — for knowing when food is actually done. Chicken breasts pulled at 155°F, rested 3 minutes to climb to 160°F, are juicy. The same breasts cooked "until the juices run clear" (old guidance) reach 175°F and are dry. A $35 Lavatools Javelin Pro Duo is 3 seconds read time. Buy it, calibrate it in ice water (should read 32°F), and never guess again.
Example 1 — a Nigella Lawson chicken recipe. Recipe: "180°C for 90 minutes." Convert: (180 × 9/5) + 32 = 356°F. Round to your oven's nearest setting — 350°F. Adjust cook time: +5 min to compensate for the 6°F lower temp. Total: 350°F for 95 min.
Example 2 — a Thomas Keller lamb recipe. Recipe calls for 425°F sear then 325°F roast. Convert: 218°C sear then 163°C roast. For a UK/European oven, round to 220°C and 160°C. The 2-3°C loss at the low end means +5 min on roast time.
Example 3 — sous vide steak. "132°F medium-rare, 2 hours." Convert: (132 − 32) × 5/9 = 55.5°C. Set your Anova/Breville sous vide to 55.5°C. For a perfect doneness target, the number is 54.5°C (130°F) for classic medium-rare, 56.5°C (134°F) for a step firmer.
Sous vide (precision cooking in temperature-controlled water) demands exact numbers. Common targets:
Candy temperatures are unforgiving — a 5°F miss on caramel turns clear syrup into burnt coffee-dark. Dial in each stage:
Should I use convection or conventional? Convection for roasting vegetables (aggressive browning), large roasts (even cooking), and cookies (uniform batches across multiple racks). Conventional for cakes (gentler rise), delicate pastries, and anything you don't want browned on top.
Why does my oven take so long to preheat? Most home ovens reach the set temperature in 8-12 minutes for 350°F, 15-20 min for 450°F. But the beep sounds as soon as the heating element hits the sensor's target — the oven walls are still cold. For baking, preheat 15-25 minutes longer than the beep.
What's the hottest temperature a home oven reaches? Standard electric: 500-550°F (260-290°C). Some gas ovens: 600°F. Neapolitan pizza requires 800-900°F, achievable only with pizza steels + broiler combo or a dedicated outdoor pizza oven (Ooni, Gozney).
How do I calibrate my oven? Place an oven thermometer (Rubbermaid, OXO, CDN) on the center rack. Set oven to 350°F. After 30 min, read. If it says 320°F, bake recipes at 380°F when they call for 350°F. Or use your oven's built-in calibration in settings (most modern ovens support ±35°F offset).
Does altitude affect internal meat temperatures? No — meat doneness is controlled by protein denaturation, which happens at fixed temperatures regardless of altitude. Altitude affects boiling water (lower BP at altitude), which affects braise and poach times but not roasts.
Is it safe to eat pork at 145°F (medium)? Yes, since 2011 USDA update. Trichinella is functionally extinct in US commercial pork due to feed regulations. 145°F pink pork is safe and vastly juicier than the old 160°F target.
Can I eat ground beef at less than 160°F? USDA says no. In practice, whole-muscle beef ground at home and cooked promptly at 135°F is safe for healthy adults — the surface bacteria are the risk and surface gets seared. Commercial ground beef: cook to 160°F because the grinder is a bacterial distribution machine.
What does "rest 5 minutes" actually do? Carryover cooking raises internal temp 3-5°F in small cuts, 5-15°F in large cuts. During rest, muscle fibers relax and juices redistribute. A rested steak loses 5% of moisture when sliced; an unrested steak loses 15-20%.