Celsius and Fahrenheit
Use °F = (°C × 9/5) + 32, or °C = (°F − 32) × 5/9. For example, 180°C equals 356°F mathematically. Your oven may offer a nearby setting rather than that exact number.
An oven dial is a practical choice
The exact converted value and a nearby dial setting serve different purposes. Read your recipe and appliance instructions when choosing a setting. A rounded dial suggestion should always be marked as approximate.
Fan settings are a separate question
Converting 180°C to Fahrenheit does not turn a conventional-oven recipe into a convection recipe. Keep the unit conversion separate from any appliance-specific adjustment.
Do not scale cooking time with temperature
There is no general formula that makes a dish finish correctly by trading heat for minutes. Use a suitable recipe and check progress using the recipe’s own guidance.