It is so that, in most transactions, both parties involved in the transaction know exactly what is being traded.
Generally they use the SI system
The International System of Units
The system of units scientist use to measure the properties of matter are the SI units.
Standard units are used for measurmen as there is a system called the SI units and that is considered as the international system of units that is why we use standard units for measurment .
Although it is familiar with the International system, the United States uses the English system of units.
Scientists use a single system of units, such as the International System of Units (SI), to ensure consistency, accuracy, and ease of communication between researchers worldwide. Using a standardized system avoids confusion and errors that can arise from the use of different units in scientific measurements and calculations.
They use the SI, or System International.
This system is SI: the International System of Units, universally accepted.
How do you change metric units?
Most scientists use the Metric system of units of measure, also called the Système international or SI system
All units used in the aerospace industry are SI units.
In the SI system the units are Joules. You can also use ftlbf (footpoundforce). For thermal energy use calories or BTU