Celsius to Gas Mark Oven Dial Converter for Baking

Setting a Gas Oven from a Recipe Written in Celsius

Continental and modern British recipes give oven temperatures in Celsius, but a great many gas cookers in the UK and Ireland still have a dial numbered from ¼ to 10. Nothing on that dial says 180, so the recipe has to be translated before the tin goes in. Type the Celsius figure on the left and the matching mark appears on the right.

How this one works: Gas Mark is a stepped dial rather than a multiplication, so the converter reads the standard oven table — 140°C = 1, 150°C = 2, 160°C = 3, 180°C = 4, 190°C = 5, 200°C = 6, 220°C = 7 — and interpolates between the steps. A recipe calling for 190°C therefore returns Gas Mark 5, and 170°C returns 3.5.

When the Dial and the Recipe Disagree

European Cookbooks

French, German and Italian baking books quote Celsius throughout, leaving a gas-cooker owner to guess at the dial position for every single recipe.

Recipes from a Phone

Video and blog recipes almost always state Celsius, and the comments rarely include a gas equivalent, so the number has to be converted mid-cook.

A Gas Cooker in a Metric Kitchen

Rented flats and older houses often pair a numbered gas dial with a household that thinks entirely in Celsius, so the translation happens several times a week.

From Recipe Line to Oven Dial

Enter the conventional Celsius figure

Use the temperature the recipe prints for a normal oven. If the recipe quotes a fan figure instead, add 20 back on first — the gas table describes conventional heat.

Read the mark and round to the dial

Results land on whole numbers for the standard temperatures and in between for everything else. A value of 3.5 means the pointer sits midway between 3 and 4 on the cooker.

Check a mark you have already set

The swap arrows put Gas Mark on the left, which is the quick way to confirm that the dial you turned to actually corresponds to the recipe's Celsius figure.

Note it on the recipe

Copying gives you the plain number, which is handy for pencilling a permanent gas equivalent into the margin of a cookbook you use often.

Both boxes remain editable throughout, so nothing needs resetting when you want to work backwards. The dropdowns also list Fahrenheit, Kelvin and Rankine, which covers American recipes that give oven heat in Fahrenheit instead.

Fan Ovens, Gas Dials and the Twenty-Degree Rule

A fan oven circulates air, so it cooks as though it were roughly 20°C hotter than the dial says. The usual instruction is to subtract 20 from a conventional recipe temperature when using fan heat. Gas ovens are almost never fan-assisted, which means the gas column below matches the conventional column and not the fan one.

Conventional °C	Fan °C	Gas Mark	What it suits
140°C	120°C	1	Slow casseroles and drying meringues
150°C	130°C	2	Rich fruit cake and long, gentle bakes
160°C	140°C	3	Baked custards and slow roasting
180°C	160°C	4	The default for sponge cakes and biscuits
190°C	170°C	5	Scones, small pastries and crumbles
200°C	180°C	6	Roast vegetables and covered pies
220°C	200°C	7	Bread, pizza and hot-oven roasting

Between-Mark Answers

Temperatures that fall between two standard steps return a decimal such as 3.75, telling you how far past the printed mark to nudge the pointer.

Dial-Back Verification

Turning the pair around lets you start from the mark you have set and confirm the Celsius temperature it represents before the oven finishes preheating.

Floury-Fingers Typing

Spaces inside a typed figure are ignored and a comma is accepted in place of a full stop, so a hurried entry mid-bake still converts cleanly.

Held Inside the Dial Range

Anything below 107°C returns the lowest mark and anything above 260°C returns 10, because a gas dial has no settings outside that span.

Oven Setting Questions

Do I subtract 20°C for a fan oven before converting?

Not for a gas dial. The 20-degree reduction exists to make a fan oven behave like a conventional one, and the gas table is already built around conventional heat. Convert the recipe's conventional figure directly; only subtract 20 if you are cooking the same dish in an electric fan oven instead.

Why does the result show 3.5 when my dial has no half marks?

Because 170°C sits exactly halfway between the 160°C and 180°C steps. Ovens are not precise enough for the difference to matter much — set the pointer between 3 and 4, or pick the lower mark and add a few minutes to the bake.

What happens with a temperature below 107°C or above 260°C?

The result is held at the end of the range — the lowest mark below 107°C, and 10 above 260°C. Recipes in that territory, such as very low overnight drying or a pizza stone at 280°C, are outside what a domestic gas dial can express at all.

My printed chart says Gas Mark 3 is 170°C. Which is right?

Published gas charts genuinely disagree by a step or so, because the scale was never standardised to the degree. This converter uses 160°C for mark 3, matching the table it interpolates from. Either figure lands well inside the swing of a real oven thermostat.

Do baking times change once I move to a gas oven?

Often slightly. Gas heat is moister and less evenly distributed than electric heat, so the top of the oven runs hotter than the bottom. Keep the recipe timing as a starting point, check earlier than usual, and rotate the tray once during the bake.

Celsius to Gas Mark