Oven Temperature Converter (French Gas Mark / Thermostat)
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
The French oven thermostat scale converts to Celsius by multiplying by 30: thermostat 6 corresponds to 180 °C, a very common baking temperature.
Explanation
The thermostat system (noted "th."), historically used on French ovens, grades temperature from 1 to 10 (sometimes higher), with each step corresponding to 30 °C: th.1 = 30 °C, th.6 = 180 °C, th.10 = 300 °C. Many current ovens display temperature directly in Celsius, but some recipes, especially older French ones, still give a thermostat number rather than an exact temperature. English-language recipes (American or British) almost always use Fahrenheit, a different scale that also needs converting: this calculator covers all three units and converts in any direction. For a general temperature conversion (not specific to cooking), see our temperature conversion calculator.
Example: converting 180 °C to thermostat and Fahrenheit
Inputs
Value: 180. Starting unit: Celsius.
Calculation
Thermostat = 180 ÷ 30 = 6. Fahrenheit = 180 × 9/5 + 32 = 324 + 32 = 356.
Result
180 °C corresponds to thermostat 6, or 356 °F.
Frequently asked questions
Why do some ovens show a thermostat number instead of degrees?
The thermostat scale is a historical French system, simpler to mark mechanically on older dial ovens. Modern electronic ovens almost always display the temperature directly in Celsius, but many recipes, especially older or traditional French ones, still give a thermostat number out of habit.
Is the relationship thermostat = °C ÷ 30 always exact?
It's very widely used as a conversion reference (and confirmed by many cooking sources), but it remains a practical convention rather than a physical standard: very slight variations between manufacturers remain possible on older ovens. For precise baking, trust your oven's direct degree display first, if it has one.
How do I convert an American recipe to Fahrenheit?
Enter the temperature given in the recipe with Fahrenheit selected as the unit: this calculator immediately shows the equivalent in Celsius and thermostat. Common oven temperatures in Fahrenheit generally fall between 300 °F (about 150 °C) and 450 °F (about 232 °C).