How many minutes fit on a side of vinyl?
It always depends on musical content, for instance, a bass heavy track will take up more space on a disc than a recording of a string quartet, but here are some general guidelines:

Format Loud Level Average Level
7″ 45rpm For Up to 3 ½ minutes Up to 4 ½ Minutes
10″ 33rpm Up to 7 Minutes Up to 9 Minutes
10″ 45rpm Up to 5 ½ Minutes Up to 7 Minutes
12″ 33rpm Up to 13 Minutes Up to 15 Minutes
12″ 45rpm Up to 7 ½ Minutes Up to 9 Minutes
Album Up to 19 Minutes Up to 22 ½ Minutes