My oven just goes from 0 to 250 but it say if in Fahrenheit or Celsius. How do I tell which is?

If your oven only goes from 0 to 250, it is most likely in Celsius. There are 100 degrees Celsius between the freezing point of water (0°C) and the boiling point of water (100°C), and 250 degrees Celsius is equivalent to approximately 482 degrees Fahrenheit. It's highly unusual for an oven to have a temperature range of only 250 degrees Fahrenheit, as most standard ovens go up to at least 450-500 degrees Fahrenheit. Therefore, it's more probable that your oven's temperature is measured in Celsius.