“I’m Not Dead Yet!” Reverse Polish Notation Calculators You Can Still Buy

If you used a scientific calculator in the 1970s or 1980s, there was a fair chance that it worked differently from almost every calculator you see today. Instead of typing: …. “I’m Not Dead Yet!” Reverse Polish Notation Calculators You Can Still Buy.

Instead of typing: 2 + 3 = you entered: 2 ENTER 3 + There wasn’t even an equals key. Hewlett-Packard made this system — Reverse Polish Notation, or RPN — practically synonymous with serious scientific calculators until other players like TI and Casio got serious. Once you got used to it, ordinary algebraic calculators could feel annoyingly clumsy.

Today, RPN calculators look like a nearly extinct species. HP left the calculator market, licensing the HP calculator line to Moravia Consulting. Old HP-15Cs, 16Cs, 32Ss, 42Ss, and 48s have become collectibles.

You can still buy new hardware, build your own, or turn almost any computer or phone into a very capable RPN machine.