Oven Temperature Converter
Convert oven temperatures between Fahrenheit, Celsius, gas marks, and descriptive levels (slow, moderate, hot).
What this calculates
Old recipes, UK recipes, and oven brands all express oven temperature differently. Fahrenheit (US), Celsius (most of the world), gas marks (UK), and descriptive levels ('moderate oven') all describe the same heat. This converter shows all four side-by-side and adjusts for fan/convection ovens.
Formula & how it works
C to F: F = C × 9/5 + 32. F to C: C = (F − 32) × 5/9. Gas marks (UK): Mark 1 = 275 °F = 140 °C; each mark adds ~25 °F or 14 °C. Fan/convection: reduce by 20 °C (~35 °F) from conventional setting, or reduce time by 25 %.
Worked example
350 °F = (350 − 32) × 5/9 = 176.7 °C ≈ 180 °C. Gas Mark 4. 'Moderate oven'. Conversion to fan: 160 °C fan. A typical cookie recipe at 350 °F works at 160 °C fan or 180 °C conventional or Gas Mark 4.
Frequently asked questions
Why convert?
British recipes use Celsius and gas marks. US recipes use Fahrenheit. Vintage recipes might say 'slow oven' or 'hot oven'. Many ovens have both scales but not gas marks.
How much does fan reduce?
Roughly 20 °C / 35 °F. Some fan ovens auto-adjust if you set 'conventional' temp; others don't. Check your manual or test with a thermometer.
What's 'moderate' oven?
Loose convention: Slow 275-300 °F. Moderate 350 °F. Hot 425 °F. Very hot 475 °F+. Modern recipes specify exact temperatures.
Should I trust the dial?
Many ovens are off by 10-25 °F. A $10 oven thermometer reveals the truth. Especially worth checking before baking pastries or anything heat-sensitive.