There are 8 pints in a gallon. This is because 1 gallon equals 4 quarts, and each quart has 2 pints: 1 gallon = 4 quarts × 2 pints = 8 pints.
This measurement is based on the U.S. customary system, commonly used in cooking and liquid measurements.
There are 8 pints in 1 US gallon. When working in the UK (Imperial) system, 1 gallon will also be 8imperial pints, but also there is a difference between the size of an imperial and US pint.