a

The total size depends also on the charset, but in general varchar has to store the column value together with the length.
char “knows” the length, as it is fixed.
With MyIsam, the varchar also causes the row format to be dynamic.

You can check with:

- show table status like 'chartst%';
- select table_schema,table_name,data_length
  from information_schema.tables
  where table_schema='TT' and table_name like 'chartst%';