Excel's precision limits (15 decimal digits) seem to cause problems.

You could try a multi-precision add-in. if you still consider that Excel.

Here's one, there may be more

http://precisioncalc.com:80/

--
Kind regards,

Niek Otten
Microsoft MVP - Excel

"Diogo" wrote in message ...
| Need to calculate via Excel:
|
| mod(13^271;162653)
|
| Any thoughts????
|
| Thanks