I am creating a simple overtime calculator with if then statements. I am missing something and I am sure it is simple. Here is the code snippet.

string str_hours = txtHours.Text;
double hours = Convert.ToDouble(str_hours);
string str_payrate = txtPayRate.Text;
double payrate = Convert.ToDouble(str_payrate);
string str_paycheck = txtPaycheck.Text;
double paycheck = Convert.ToDouble(str_paycheck);

if (hours <= 40)

paycheck=hours * 40;

else

paycheck=40 * payrate + (hours - 40) * 1.5;


txtPaycheck.Text = str_paycheck;