Oven Temperature Converter
Enter a temperature in any system and all four show instantly: gas mark, conventional oven °C, fan/convection oven °C, and Fahrenheit. With a verbal description. Nothing uploaded.
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Equivalents
Learn more: gas marks, Celsius and fan ovens
How gas marks relate to degrees
Wikipedia's gas mark article lists gas mark 1 as 275 F and each mark after that as 25 F higher, up to 500 F at gas mark 10. So gas mark 4 is 350 F and gas mark 8 is 450 F. In Celsius the same marks come out as uneven numbers such as 140, 150, 170, 180, because 25 F steps are rounded to whole degrees.
The scale is not proportional. Gas mark 8 is not twice as hot as gas mark 4, since 450 F is 100 F above 350 F and not double it. The tool uses a lookup table and not a formula, and it matches a temperature to the nearest gas mark in the table.
Different tables, small differences
Published tables do not agree on every mark. For gas mark 3, Wikipedia gives 170 C, the Beko cooker guide gives 165 C and this tool uses 160 C. Gas marks 4 to 8 agree closely, at about 180, 190, 200, 220 and 230 C. Beko says its conversions are approximate and can vary by model, so check your oven's own manual when you can.
Fahrenheit results are rounded to the nearest 25 F, because oven dials step that way. That is why 180 C shows as 350 F and not the exact 356 F. If you type a Fahrenheit temperature, the tool echoes it back.
Fan ovens
In the tool's table, the fan setting is 20 C below the conventional one for every gas mark, so gas mark 4 is 180 C conventional and 160 C fan. A 20 C drop is 36 F exactly, which on oven dials is about one 25 F step, so 350 F conventional is about 325 F fan. Manufacturers differ, so treat this as a starting point and check the food.
FAQ
Why not multiply the gas mark by a number to get Celsius?
The Celsius values are rounded versions of 25 F steps, and gas marks 1/4 and 1/2 are partial steps below mark 1. A lookup table is simpler and avoids the rounding errors a formula would add.
What is the fan oven offset in Fahrenheit?
The tool's 20 C offset is 36 F exactly. On a dial that moves in 25 F steps, it works out to about one step lower, for example 350 F conventional and 325 F fan.
Is gas mark 4 moderate?
Yes. Wikipedia describes gas mark 4, 350 F or 180 C, as moderate or medium. Marks 5 and 6 are moderately hot, 7 is hot and 8 and 9 are very hot.