This year is the 25th anniversary of the launch of the HP 12c. I have had mine for about 20 years. The logo has been chipped off, two of the foot pads are missing, its scratched, dented and scuffed.

But it still works like a charm. I have purchased more powerful upgrades to the 12c by HP but I was soon back to my baby. Billions of numbers have shown through the dirty display and a whole lot of appraisals got done using this nifty tool. I have become protective of it, getting concerned when it gets swapped accidentally in the office with a newer one thats shiny, clean and unweathered. Its just not the same.

I have only changed my battery once in twenty years. I remember taking a Cap A class offered by the Appraisal Institute and the logic given for learning the J-Factor and K-Factor was that it would come in handy if you were on the witness stand as an expert and your HP 12c battery died. I kid you not.

The HP 12C was the world’s first horizontal financial calculator. Its innovative design and breakthrough Reverse Polish Notation (RPN) entry forever changed the way students and professionals reach their goals. After 25 years, this iconic calculator is still sold under its original name and model number and retains its world-famous horizontal design.

I even use the software equivalent on my laptop. In addition, my Mac OSX operating system allows me thankfully, to change the system calculator to use reverse polish notation (RPN)

Remember: 1 enter 1 +

Should I finally break down and buy a new one?



11 Responses to “A Badge Of Honor: My HP 12c And Reverse Polish Notation”

  1. ltjbukem says:

    great article! i have worked on wall st for 10 years and have only ever learned how to use this 12c…

    in college i used to have a texas instruments for my engineering classes, but this 12c is straight butter!

  2. Cheryl says:

    I have a 20 year old one too! No icon, no foot pads and the batteries are taped in place. Just can’t part with it!

  3. Mark Troen says:

    Jonathan, I have had my HP12C since my Wharton days in 1981 when it first came out. This is the unsung hero of real estate development, finance, etc. and was especially valuable before computers became the norm a short few years later. I used to create complete “spreadsheet” macros and formulas on the 12C (now Excel has replaced that need).

    A funny note: I actually lost my original HP12C on a Delta flight from NY to Atlanta in 1992. I went to report it to the Delta lost and found at Hartsfield airport and the attendant said not to worry. Instead, she had hundreds of lost calculators in the bin – and proceeded to pull out a nearly identical shopworn HP12C from her supply. She told me to take it and had no doubt that when the next person came in looking for an HP12C calculator, my calculator would have by then shown up in lost in found and would simply give that to the next individual. While I was initially distressed at losing the calculator (and never had scribed my name on it like some people I know), this calculator quickly filled in as a “replacement” and has performed admirably ever since!

    Mark Troen, CRE, FRICS Executive Vice President Racebrook Capital, LLC 126 East 56th Street New York, NY 10022

  4. Jonathan J. Miller says:

    Great feedback. In this era of disposable everythings, its nice to see something stick around. HP has to have mixed feelings though. They built these things so well, the original buyers never replaced them.

  5. Patrick says:

    Hi, A simple question. How do you change the screen format from (number example) 123, to 123. Some how my 12c shows numbers using “,” at the end of a number rather than “.”. On a long number it uses “.” to separate thousands. I guess I had switched something accidentiality. Can you tell me how to swirch it back? Thanks, Patrick

  6. Roy says:

    To get rid of the comma, turn the calculator off, hold down the decimal point key, press [on], release the decimal point key.

  7. John Conners says:

    I can’t resist adding my comments to your blog. I purchased one of the very first HP12Cs as a replacement for my HP38. I was surprised to find that W.Bell in Chicago (long out of business) was the first with a handful available. We were in a period of very high interest rates and the Boston publisher of rate tables could not keep up with the upward changes. My employer (Paine Webber Real Estate Securities) was running calculations on a Main Frame computer at night so that traders could quote and bid on real estate securities the next day. The traders were amazed that I could easily come up with the very same information on a real time basis for our salesmen, and with such accuracy. I came up with “cheat sheets” for the traders and it wasn’t long until they all had there own HP12Cs. I still use that same calculator (the case is shot) and am surprised at how much better quality it is as compared to the new 12Cs manufactured off shore.

  8. David says:

    Roy Says:

    April 27th, 2006 at 1:47 pm To get rid of the comma, turn the calculator off, hold down the decimal point key, press [on], release the decimal point key.

    Thanks Sir!!! I don’t know how I got the comma — but this was the key.

  9. OSMAN KILIC says:

    I am an HP fan..I found out they have come up with a platinum model for HP12C’s anniversary for nearly the same price I have bought mine 25 years ago..I couldn’t resist leaving a message when I saw this blog..I had mine since my junior year of college..Before I was using 38C revolutionary with constant memory:-) The days of no PC..Later I bought an HP 85 first portable PC and then used palmtops HP 99LX 100LX 200LX..I wish they continued or updated that line..I miss it a lot still keep the last one:-( During the whole time I always had my HP12C couldn’t ever part with it..I don’t even remember changing its battery more then once or twice..I loved being amused with a smile on my face when someone asked me to use my calculator and then ask..hey where is the equal sign..It is for sure THE doesn’t even takes a licking tile Timex and keeps on ticking:-) HP has made some top products in the past..Was pioneer in whatever it made..I think today they have challanges right, left and center.. Thanks, OSMAN

  10. Pete Smith says:

    I purchased an HP 35 in 1974 for $399. Four register stack but did trig and log functions so I was out of engineering exams early. I still have it and it still works with RPN. When I became an executrive I bought a 12 C (20 years ago) and still have it. I also have a 32sII for advanced engineering. These guys are the best in calculators and RPN has saved me at least a million keystrokes over the years. Can you say “ENTER”!

  11. Dave Adams says:

    If your 12C starts going crazy like mine did… I hit a key and wrong numbers get regestered and multi numbers….its got static in the system….after working with HP headquarters the solution was….remove batteries and use a coin,,dime to bridge the contacts in battery compartment. and hold down ON key for 15 sec. if that does not work keep batteries out for 24 hours……I did that and she works fine. aparently I left it too close to some stereo speakers on my desk.