Gas Mark to Celsius Converter

Gas Mark to Celsius Converter

Convert oven temperatures between gas mark, Celsius, fan and Fahrenheit.

Fan ovens circulate hot air, so they cook at about 20°C lower than a conventional oven. If your recipe already gives a fan temperature, use it as it is.
Gas mark 4 is
180°C
Moderate oven
4gas mark
180°Cconventional
160°Cfan oven
350°FFahrenheit
Gas°CFan °C°FHeat

Oven dials and recipes round temperatures, so small differences of 5 to 10 degrees are normal.

Older British cookbooks and many family recipes give oven temperatures as gas marks, while modern electric ovens show degrees. This gas mark to Celsius converter works in both directions, so you can find the right gas mark for a recipe written in °C or °F, and it also gives the conventional and fan oven temperature in °C plus the Fahrenheit figure used in American recipes.

Gas mark to Celsius converter showing gas mark 4 as 180°C, 160°C fan and 350°F
How the Gas Mark to Celsius Converter works: gas mark in, conventional, fan and Fahrenheit temperatures out.

What Is a Gas Mark?

Gas mark is a temperature scale used on gas ovens in the UK and Ireland. It runs from gas mark 1/4 for very low heat up to gas mark 9 for very hot cooking. Each full mark from 1 upwards is roughly 25°F, or about 14°C, hotter than the one before.

Because the scale is not a direct formula, the converter uses the standard UK chart. Gas mark 4 is 180°C or 350°F, gas mark 6 is 200°C or 400°F. For a fan oven, take about 20°C off the conventional figure, so gas mark 4 becomes 160°C fan.

How to Use the Gas Mark to Celsius Converter

Step 1: Choose What to Convert From

Select Gas mark if your recipe uses gas marks, or choose °C or °F if you need to find the matching gas mark for a gas oven.

Step 1: choose to convert from gas mark, °C or °F

Step 2: Enter the Temperature

Pick a gas mark from the list, or type a temperature in degrees. Results update straight away as you change the value.

Step 2: select the gas mark or enter a temperature

Step 3: Tick Fan Oven if Needed

If you cook in a fan assisted oven, tick the fan option. The main result then shows the lower fan temperature so your food does not overcook. If your oven is electric, the electricity cost calculator shows what an hour of baking costs at today's prices.

Step 3: tick the fan oven option if your oven has a fan

Step 4: Read Your Oven Temperatures

You will see the gas mark, conventional °C, fan °C and °F, along with a description of the heat. The full chart highlights your row so you can compare nearby settings, and the time duration calculator is handy for working out how long a slow roast has been in.

Step 4: read the converted oven temperatures and chart

Gas Mark Conversion Chart

Gas mark°CFan °C°FDescription
1/411090225Very cool
1/2120100250Very cool
1140120275Cool
2150130300Cool
3170150325Warm
4180160350Moderate
5190170375Moderately hot
6200180400Hot
7220200425Hot
8230210450Very hot
9240220475Very hot

Every oven runs slightly hot or cold, so an inexpensive oven thermometer is worth having if bakes regularly come out under or over done. Fan ovens cook faster because moving air transfers heat more efficiently, a principle explained in this guide to convection ovens. Many fan oven owners also shorten cooking times slightly.

Frequently Asked Questions

What is gas mark 4 in Celsius?

Gas mark 4 is 180°C in a conventional oven, 160°C in a fan oven and 350°F.

What is gas mark 6 in a fan oven?

Gas mark 6 is 200°C conventional, which is about 180°C in a fan oven.

What gas mark is 180°C?

180°C is gas mark 4, a moderate oven used for most cakes and bakes.

How much lower should a fan oven be?

Set a fan oven about 20°C lower than the conventional temperature given in the recipe.

What is gas mark 7 in Fahrenheit?

Gas mark 7 is 425°F, which is 220°C conventional or 200°C fan.

What is the lowest gas mark?

Most gas ovens start at gas mark 1/4, about 110°C, which is used for drying meringues and very slow cooking.