If not then convert this to log_10 (log base 10) with the log conversion formula.
log_x(Y)= (log_z(y))/log_z(a).
3= 2.718 281...
So ln(2*pi) = log_10(2*pi) / log_10(e) = approx. .7981799 / .434294 = 1.8379.
When using the calculator, don't round the intermediate numbers.