PURPOSE: To obtain a printer capable of properly calculating the printing ratio and outputting the calculated results by a method wherein the ratio of the number of actually printed letters to the number of maximum printable letters is computed from the number of printed letters counted and the digital value produced by a paper feeding counter.

CONSTITUTION: A print counter 9 is used to count the number of letters set in a digit buffer 7 or the number of letters printed on a line printer sheet and a paper feeding counter 10 is employed to compute the number of lines on the paper fed by a paper feeding control part 8. Based on the counted number (m) of printed letters and the calculated value (n) of the amount of paper fed by the paper feeding counter 10, the ratio of the number of actually printed letters to the number of maximum printable letters A=m/(n×k) is produced in a printing ratio operational circuit when the number of digits on a line is k.