Gas mark 3 in a fan oven is equivalent to 325°F (160°C) . This temperature is considered moderate and is suitable for cooking dishes that require a gentle heat, such as cakes, casseroles, and slow-cooked meats. It is important to note that fan ovens typically have lower temperatures than conventional ovens because the fan circulates hot air around the inside of the oven and into the food, ensuring a more even temperature and food thats cooked more quickly.