A quart is a unit of volume measurement, it is equal to one fourth of a gallon. It is roughly equal to 4 cups, 2 pints, and 32 fluid ounces. The abbreviation for quart is "qt."
In the US and the UK, a quart is equal to approximately 0.946 liters, which is equal to 946.35 milliliters (ml). However, in countries that use the International System of Units (SI), the liter is used, and a quart is equal to exactly 1 liter.
It's important to note that, when converting between different units of measurement, it's essential to use the correct conversion factor and to be aware of the system of measurement being used. This is because, depending on the system of measurement, the conversion factors can differ. In this case, the conversion factor of US and UK is 1 quart = 0.946 liter = 946.35 milliliters, while in countries that use the SI system is 1 quart = 1 liter.