One liter is a unit of volume in the metric system, equivalent to 1,000 milliliters. Therefore, 1.25 liters is equal to 1,250 milliliters. This measurement is commonly used for liquids, such as water, beverages, and cooking ingredients. In practical terms, 1.25 liters is about the size of a large bottle of soda or a standard milk carton. It can also be visualized as slightly more than a quart, which is often used in cooking and food preparation in various countries.