Math and Arithmetic

There are 8 pints in one US gallon. (2 pints to a quart, 4 quarts to a gallon)

Note: US gallons and UK gallons are not the same, as with pints. For safest conversion we can go via Litres as its a fixed international standard.

US gallon = 3.79 Litres

UK gallon = 4.5 Litres

US pint = 473 mL

UK pint = 568 mL

Therefore there are roughly 8 pints in a gallon if you are using the same country's standards. But the UK (Imperial) Gallon is larger than the US Gallon, and there would only be 6.7 Imperial pints to a US gallon.
8 pints

There are 4 cups in 1 quart, but the size of the quart depends upon whether you are using the Imperial or US system. The US and Imperial systems are completely different, and often misunderstood.

Starting with the ounce:

• The US fluid ounce is 29.57 ml
• The Imperial fluid ounce is 28.41 ml

Cups:

• There are 8 US fluid ounces in 1 US cup (236.6 ml)
• Technically, there is no 'cup' in the Imperial system, but using the ratio of two cups per pint, there would be 10 Imperial fluid ounces in 1 Imperial cup (284.1 ml). No one would ever consider using a 10 ounce cup in the Imperial system. Colloquially, 8 Imperial ounces are used for an Imperial cup, but this is not a recognized Imperial standard, and leads to confusion. In the Imperial system, it is best to use only pints (or half pints), and to never refer to 'cups.'

Pint:

• There are 16 US fluid ounces (2 cups) in 1 US pint (473.2 ml)
• There are 20 Imperial fluid ounces in 1 Imperial pint (568.3 ml). In common parlance in the Imperial system, a cup is considered to have 8 ounces, thus giving rise to 2.5 cups per pint, but this is not correct. There are no 'cups' in the Imperial system.

Quart

• There are 32 US fluid ounces (2 pints, or 4 cups) in 1 US quart (946.4 ml)
• There are 40 Imperial fluid ounces (2 pints) in 1 Imperial quart (1,136 ml)