Most recipes written before 2010 use Fahrenheit; most European recipes use Celsius. Gas marks are still common in older British cookbooks. This guide covers all three plus the adjustments needed when using convection (fan-assisted) mode.

Temperature Conversions

Description °F °C Gas Mark
Very low250°F120°CGas ½
Low300°F150°CGas 2
Moderately low325°F165°CGas 3
Moderate350°F175°CGas 4
Moderately hot375°F190°CGas 5
Hot400°F200°CGas 6
Hot425°F220°CGas 7
Very hot450°F230°CGas 8
Very hot475°F245°CGas 9
Broil / Grill500°F+260°C+Gas 10

Convection (Fan) Oven Adjustments

Conventional Setting Convection Temp Convection Time Notes
350°F / 175°C325°F / 165°CSame timeBaked goods — reduce temp
400°F / 200°C375°F / 190°CReduce by ~20%Roasting — temp and time
425°F / 220°C400°F / 200°CReduce by ~20%High-heat roasting
Any temperatureSame tempReduce by 25%Reduce time, not temp

Apply one adjustment only — either reduce temperature by 25°F / 15°C OR reduce time by 25%. Applying both overcorrects.

Common Roasting Temperatures and Times

Food Temp Time Doneness
Chicken, whole (4 lb)425°F / 220°C60–75 min165°F / 74°C thigh
Chicken thighs, bone-in425°F / 220°C35–45 min165°F / 74°C
Chicken drumsticks425°F / 220°C35–40 min165°F / 74°C
Salmon fillet (1 inch)400°F / 200°C12–15 minOpaque, flakes
Whole fish (2 lb)400°F / 200°C25–30 minFlesh pulls from bone
Pork tenderloin425°F / 220°C20–25 min145°F / 63°C, rest 5 min
Pork loin roast (2 lb)350°F / 175°C60–75 min145°F / 63°C
Sheet pan shrimp400°F / 200°C8–10 minPink and curled

Vegetable Roasting

Vegetable Temp Time Notes
Cauliflower florets425°F / 220°C25–30 minShake halfway
Broccoli florets425°F / 220°C20–25 min
Brussels sprouts, halved400°F / 200°C25–30 minCut side down
Sweet potato wedges400°F / 200°C30–35 min
Mixed sheet pan veg425°F / 220°C20–30 minCut uniform size
Whole garlic head400°F / 200°C40–45 minWrapped in foil

Frequently asked questions

How do I convert a conventional recipe to convection?

The standard rule: reduce temperature by 25°F (15°C) and keep the same time, or keep the same temperature and reduce time by 25%. Apply one adjustment only. Convection circulates hot air and cooks faster and more evenly than conventional; both adjustments together overcorrect.

How long should I actually preheat my oven?

Most ovens signal "ready" when the air temperature reaches the target, but the oven walls and rack still need 10 to 15 more minutes to fully absorb heat. For anything you want even browning on — bread, cookies, roasts — wait 15 minutes after the preheat signal before putting food in.

Why does food brown unevenly in my oven?

Every oven has hot spots — areas where the heating element is closer or where air circulation is stronger. The back of most ovens runs hotter than the front. Rotate pans 180° halfway through cooking and avoid the top rack for anything that browns easily.

What is the difference between bake and broil?

Bake uses all heating elements (top and bottom) to surround food with even heat — used for most cooking. Broil uses only the top element at maximum heat to brown and char the surface — used for finishing dishes, melting cheese, or caramelizing the top of a gratin. Most ovens run 500–550°F under broil.