Wanting to center text

This code will justify the text "Start Program" in the left center of the terminal window. I'd like it in the center. If anyone has any suggestions, much appreciated.

cols=$( tput cols )
rows=$( tput lines )

message=Start Program

input_length=${#message}

half_input_length=$(( $input_length / 2 ))

middle_row=$(( $rows / 2 ))
middle_col=$(( ($col /2 ) - half_input_length ))

tput clear

tput cup $middle_row $middle_col
tput bold

echo Start Program

tput sgr0
tput cup $( tput lines ) 0