Use this approximation for the cummulative area under the Normal curve =0.5+z*0.389377141853663+z^2*1.08529111489983E-11+z^3*-0.0513483086730824+z^4*-1.50619079729924E-12+z^5*0.00335208405946254 where -2.5 < z < 2.5 can use them for only the above Z=standard Normal this way U can use it in other Non MS software