Units
Gas mark converter
Gas marks beside conventional °C, fan °C and the chart’s °F.
How to use it
- Choose the gas mark from ¼ to 9.
- Read the conventional °C, the fan °C and the Fahrenheit figure printed on UK charts.
- Use an oven thermometer if the oven runs hot or cool. Fan is 20°C lower on this chart.
The BBC chart, including fan
Conventional and fan temperatures follow the BBC Good Food conversion guide. Gas mark 4 is 180°C conventional and 160°C fan. Gas mark 6 is 200°C and 180°C fan. Gas mark ¼ is 110°C and 90°C fan. On every mark in that guide the fan column is 20°C below the conventional column.
A fan oven moves the air, so the lower setting is there to keep the same cooking. If a recipe already says “fan” or “convection”, it has usually applied that drop. Applying it twice undercooks the outside and leaves the middle undone.
The Fahrenheit column is rounded
UK recipes print gas mark 4 as 350°F, gas mark 6 as 400°F and gas mark 9 as 475°F. Those are the rounded chart figures. The exact conversion of 180°C is 356°F, and 200°C is 392°F. This page keeps the chart figures in the Fahrenheit column and sends you to the Celsius converter when you want the exact temperature.
Ovens differ, especially older gas ovens and a fan oven with a hot spot at the back. An inexpensive oven thermometer tells you what this oven does at gas mark 4. Shelves matter as much as the dial: the top of a conventional oven is hotter.
Questions
What is gas mark 4 in Celsius?
180°C in a conventional oven, and 160°C in a fan oven, on the BBC Good Food chart.
Why is gas mark 4 shown as 350°F when 180°C is 356°F?
The Fahrenheit column on UK gas-mark charts is rounded. 350°F is the figure those charts print. The exact conversion lives on the Celsius page.