OK.. Math is NOT my forte ... I am converting a site from ASP to PHP ... And this calc is in the ASP Code : $nMonthlyInterest = $nRate / (12 * 100) //' Calculate monthly payment $nPayment = $nPrincipal * ( $nMonthlyInterest / (1 - (1 + $nMonthlyInterest) ^ -$iMonths)) Which then gives me in PHP 0.0010416666666667 = 1.25 / (12 * 100); -2.1701388888889 = 25000 * ( 0.0010416666666667 / (1 - (1 + 0.0010416666666667) ^ -12)) :: ^ is the problem ... The solution SHOULD be 2,097.47 ... Not 2.17 Would be willing to help correct this and make it valid in PHP? -- Stephen Johnson c | eh The Lone Coder http://www.thelonecoder.com continuing the struggle against bad code http://www.fortheloveofgeeks.com I¹m a geek and I¹m OK! --