1. The units named after scientists are not written with a capital initial letter.
2. The symbols of the units named after scientist should be written by a capital letter.
3. Small letters are used as symbols for units not derived from a proper name.
4. No full stop or other punctuation marks should be used within or at the end of symbols.
5. The symbols of the units do not take plural form.
6. When temperature is expressed in kelvin, the degree sign is omitted.
7. Use of solidus is recommended only for indicating a division of one letter unit symbol by another unit symbol. Not more than one solidus is used.
8. Some space is always to be left between the number and the symbol of the unit and also between the symbols for compound units such as force, momentum, etc.
9. Only accepted symbols should be used.
10. Numerical value of any physical quantity should be expressed in scientific notation.