Free RPN Calc

A free scientific RPN (reverse polish notation) calculator for everyone.

This calculator offers three display formats:
- standard
- scientific: number always displayed with Exx
- engineer: number displayed with Exx format where xx is a multiple of 3.
You toggle between these three formats by pressing the "Format" key.

This calculator has a stack of 4 numbers:
- t
- z
- y
- x : the number currently displayed
When an operation is performed, the stack is popped, but the value in t remains, like in HP calculators.

In Reverse Polish Notation the operators follow their operands; for instance, to add three and four one would write "3 4 +" rather than "3 + 4". RPN calculators do not use parenthesis and require less key pressing than usual calculators. For example 3 * (7 - 5) + 2 in RPN is 7 5 - 3 * 2 + .