You could look at existing higher-precision floating point libraries like: http://www.nongnu.org/hpalib/ It doesn't appear to be designed with a microcontroller in mind, but it does support up to 149 digits of accuracy (62 BYTE mantissa, if I read the intro page correctly!) BillW -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist