US pints to liters (pt to L)

One US pint is exactly 0.473176473 liters. That is a definition rather than a measurement: the imperial and US customary units were fixed against metric ones by the 1959 international yard and pound agreement, so this factor does not drift and will not be revised.

Worked through: 4 pt x 0.473176473 = 1.89271 L.

Going the other way, one liter is 2.113376419 US pints.

For mental arithmetic: Halve it and take off 5%. Two US pints is 0.95 liters.

This is the US pint of 473 ml, and the pint is the unit where the two systems differ most visibly because it is served in a glass. A British pint is exactly 0.56826125 liters (an eighth of an imperial gallon), so it is 20% larger than the American one, and a pint of beer in London is 568 ml while a pint in New York is 473. The British pint is a legally protected measure for draft beer and cider, and the American one is not, which is why American 'pint' glasses often hold rather less than a pint once there is a head on the beer. This converter's pint is the US one; for the British, multiply by 0.568.

Precision is worth matching to the input. A measurement given as 0.5 pt carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.