US gallons to US pints (gal to pt)

One US gallon is exactly 8 US pints. The US liquid system is built by halving (gallon, half-gallon, quart, pint, cup), and every step is exactly two, so this factor is the definition and not a measurement. The same 8 holds for the imperial gallon and imperial pint, which are different sizes in the same proportion.

Worked through: 2 gal x 8 = 16 pt.

Going the other way, one US pint is 0.125 US gallons.

For mental arithmetic: Multiply by 8.

Eight pints to the gallon on both sides of the Atlantic, and that is the trap: the ratio is the same and the units are not. A US gallon of 8 US pints is 3.785 liters; an imperial gallon of 8 imperial pints is 4.546. The old rhyme 'a pint's a pound the world around' is true only of the US pint, where a pint of water weighs about 1.04 pounds; the British version is 'a pint of water weighs a pound and a quarter', because an imperial pint is 20 fluid ounces and was once defined from the weight of water.

Precision is worth matching to the input. A measurement given as 0.25 gal carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.