Thanks but ERF or ERFC that doesn't replicate =NORM.DIST(1,0,1,TRUE) = 0.84134475 - unless I'm missing something here.
you are missing something.
The error function and cumulative normal distribution differ by several factors in their definitions and have different limits of integration
(1+erf(1/sqrt(2.)))/2;=0.8413447462 replicates your result
the cumulative normal distribution is