How much oil is typically in a transformer?

The amount of oil in a transformer varies widely depending on its size and design, but generally, large power transformers can contain anywhere from several hundred liters to over 20,000 liters of oil. Small distribution transformers usually hold between 50 to 300 liters. The oil serves multiple purposes, including insulation and cooling. Therefore, determining how much oil is in a transformer is crucial for maintenance, monitoring, and ensuring efficient operation.