How to Test Your Oven Temperature Without a Thermometer

Total Time
Prep 0 mins
Cook 15 mins

Based on the method in Cooking For Geeks.


  1. To test if your oven is running cold:.
  2. Preheat oven to 375°. (186° C.).
  3. Place a small amount of granulated sugar in an oven-proof dish or on a cookie sheet lined with aluminum foil.
  4. Place in oven for 15 minutes.
  5. If your oven is calibrated correctly, the sugar will melt.
  6. If your oven is running cold, the sugar will not melt.
  7. To test if your oven is running hot:.
  8. Preheat oven to 350°. (177° C.).
  9. Follow the same procedure as above.
  10. If your oven is calibrated correctly, the sugar will not melt (although it may brown a little).
  11. If your oven is running hot, the sugar will melt.
  12. Note: ovens do not maintain a constant temperature, but cycle above and below it, so it is possible that the sugar may melt at 350° if your oven is correctly calibrated but has an extreme cycle (15° F, 8° C.).
Most Helpful

5 5

Well, am surprised b/c my oven is calibrated correctly-thought it ran cold. For first test, the sugar melted. For second test, it barely browned around the edges. Thank you Chocolatl for a very interesting "recipe".

5 5

Found out that my oven runs cold and my toaster oven runs hot.

5 5

Well, my oven runs a bit cold and, though you can't tell in the photo, the sugar browned a bit but didn't melt. This was interesting as I wasn't certain, before, which was wrong, the external oven thermometer or the internal oven thermometer.