The metric system generally used is called the 'Rationalized MKS' system.
The MKS is meter, kilogram, seconds. It's rationalized because there are adjustments made (I totally have forgotten where) so that PI only appears in formulae where circularity is involved.
Note that 'kilo' is always spelled with a small k, although generally multipliers (Mega) have upper case initial letters and 'dividers' (milli) micro) have lower case initial letters.