By approximately how many magnitudes does a true supernova brighten compared to a Nova explosion?

Answer

20 magnitudes or more

A Nova brightens by 7 to 16 magnitudes, whereas a true supernova brightens by 20 magnitudes or more, representing a difference in light output of hundreds of thousands to millions of times.

By approximately how many magnitudes does a true supernova brighten compared to a Nova explosion?
astronomystarssupernovaexplosionLuminositypeak