Oven Temperature Conversion Calculator Formula

Understand the math behind the oven temperature conversion calculator. Each variable explained with a worked example.

Use the Oven Temperature Conversion Calculator

Formulas Used

Celsius

temp_c = round((temp_f - 32) * 5 / 9)

Gas Mark

gas_mark = round((temp_f - 250) / 25)

Kelvin

temp_k = round((temp_f - 32) * 5 / 9 + 273.15)

Variables

VariableDescriptionDefault
temp_fTemperature(°F)350

How It Works

How to Convert Oven Temperatures

Formulas

  • Celsius = (Fahrenheit - 32) x 5/9
  • Gas Mark = (Fahrenheit - 250) / 25 (approximate, valid for 250-500°F)
  • Kelvin = Celsius + 273.15

    • Common Oven Temperatures

    °F°CGas MarkDescription 2501201Very Low 3001502Low 3501754Moderate 4002006Hot 4502308Very Hot

    Worked Example

    Convert 350°F to Celsius and Gas Mark.

    temp_f = 350
    1. 01Celsius = (350 - 32) x 5/9 = 318 x 0.5556 = 176.7, rounded to 177°C.
    2. 02Gas Mark = (350 - 250) / 25 = 100 / 25 = 4.
    3. 03350°F = 177°C = Gas Mark 4.

    Frequently Asked Questions

    Why do recipes use different temperature scales?

    American recipes use Fahrenheit, most other countries use Celsius, and older British recipes use Gas Mark. Converting correctly is essential for proper baking.

    Is the gas mark formula exact?

    The formula is an approximation that works well from Gas Mark 1-9 (250-475°F). Exact gas mark values are defined by manufacturers and may vary slightly.

    Should I use fan or conventional oven settings?

    Fan (convection) ovens typically run 20-25°F (10-15°C) hotter than conventional ovens. If a recipe calls for 350°F conventional, use 325°F fan.

    Ready to run the numbers?

    Open Oven Temperature Conversion Calculator