My cousin sent me this delicious American chocolate cake recipe from a food blog. The instructions said: "Bake at 350° for 35 minutes."
I grew up in a country where ovens run on Celsius. My oven knob only went up to 250. My genius brain thought: "Well, 350 sounds super hot. I'll just turn my oven knob all the way to maximum."
Twenty minutes later, the kitchen was full of smoke. 350° Fahrenheit is only about 175° Celsius! I was baking that poor cake at nearly double the required heat. Don't guess—use the calculator above.