The weight of a liter of water is approximately 1 kilogram (kg) or 1000 grams (g). This measurement assumes standard conditions, where the water is at its maximum density, which occurs at a temperature of 4 degrees Celsius (39.2 degrees Fahrenheit). At this temperature, the density of water is about 1 gram per cubic centimeter (g/cm³), and since there are 1000 milliliters (mL) in a liter, it follows that a liter of water weighs approximately 1000 grams.