Reverse Polish Notation Calculator Plus (RPNcalc+) is:
- RPN calculator (classical RPN with limitless stack)
- free
- open source
- small (~100kB compressed)
- PWA (installable, works offline, standalone)
- colorful and fun to use
- uses decimal.js for proper decimal math
deployed at https://rpncalcplus.web.app and https://rpncalculator.web.app.
RPN or postfix calculators work on a principle of stacks where you first enter operands and than operators. This makes parenthesis redundant which makes calculations much more efficient.
4 + 3: 4 enter 3 +
(4 + 3) / 2: 4 enter 3 + 2 /
((4 + 3) / 2 - 4) * 2 - (5 + 3): 4 enter 3 + 2 / 4 - 2 * 5 enter 3 + -
5 + 5: 5 enter +
cos60: 60 cos