The explanation is as follows:

At present, one liter of rice weighs 1.25 kg, 10 liter of rice is a barrel, and a barrel weighs 12.5 kg, =6.25 kg.

Extended data:

The historical origin of Mi Dou;

As a special commodity, grain in ancient times had the characteristics of large transaction volume, wide circulation and frequent income and expenditure, such as paying rent, paying taxes, buying and selling, barter and paying remuneration, and was mostly converted into grain. The rice bucket is an appliance developed with grain production, which existed as early as the pre-Qin period. "Historical Records Tian Jiazhong" wrote: "Its tax collection is based on small people's income, large people's trust, and virtue for the people."

In the Spring and Autumn Period, Tian was appointed as the doctor of the State of Qi. He was secretly kind to the people. When collecting taxes, he used a small bucket, and when distributing food to the people, he used a big bucket. However, during this period, there was no unified measurement standard for rice hoppers in all parts of the country, and the size and volume of rice hoppers in different regions were quite different. It was not until unified measurement in Qin Dynasty and Han Dynasty were further institutionalized that the standard of ten liters per bucket and ten buckets per stone was determined.

References:

Baidu Encyclopedia-Mi Dou