What is the alcohol content of light beer compared to regular beer?

It varies: This varies by brand but we can make some reasonable generalizations. Most regular beers are about 5% alcohol, and most "light beers" are closer to 4%. If you want to know for sure, you may have to look it up for a particular brand or call the company. So about 5 light beers = 4 regular beers. Clearly you can get drunk on both so be careful! More info available on the NIAAA website