The HP-12C turns 30, Goes Limited Edition

You may not know his name, but what Dennis helped bring to market – the HP-12C Financial Calculator – is well known in financial circles and still has a fanatical following three decades later.


Dennis, though normally soft-spoken, gets overwhelmed for a second. He’s here with me in Bill Hewlett’s Office.  The Bill Hewlett’s office. “This is awesome,” he says to me almost like a kid.


It was a little over 30 years ago today that Dennis, then a project manager, first showed what would be known as the HP-12C to Bill Hewlett. And now here we are (employee number 10138 and employee 21 million-something) chatting in Bill’s perfectly preserved understated office – a snapshot of Silicon Valley’s yesteryear.


“I remember when I first demoed the machine to Bill,” Dennis told me fondly, “he was holding it and asked me how it would perform a bond calculation. I tried to take the calculator back from him to show Bill how it worked. But he stopped me and said, ‘I want to do it, just tell me how.’ He wouldn’t let it go.”  It’s funny because that’s the same reaction you’d find from most people that have used a 12C over the years. In fact, it is the longest – selling product that HP has ever released.


Gold trim, faux wood paneling, and the slight slope to the digital readout screen made it a kind of nerdy status symbol of the day amongst the financial set. The characteristic ID, created by Ed Lijenwahl, really stood out as revolutionary during it’s time for a number of reasons beyond the classy chassis:



It was reliable for number crunchers. Since the 12c incorporated key financial calculations, it replaced cracking open huge financial tomes and amortization tables. It was made for – and loved by – investors and real estate professionals, accountants, loan officers and got snapped up by business students. What’s interesting is that it popularized Reverse Polish Notation to calculate results (typing "[2] [enter] [2] [+]" as opposed to typing “[2] [+] [2] [enter]"). This form of calculation was often used by engineers and scientists, but it worked so well when calculating things like interest and amortization, the business set re-learned the way they did math to use the 12C. In fact, this calculator got the blessing of the Federal Bureau of Standards (now the National Institute of Standards and Technology) – it’s legally accurate for financial fields.


It was durable. Dennis’s division manager, Dick Moore, dropped a 12C from chest height onto a cement floor to prove its design was sound. The sideways layout of the calculator – unheard of at the time – was one structural way the calculator protected the screen.



It had an incredibly long battery life. By some accounts told to Dennis, people have used the 12C for years without having to replace the batteries. The goal was to have it last at least six months with heavy duty usage. Mission accomplished—and blown out of the water!


It broke ground with revolutionary technologies for the time. When it came out, the entire device had 0.75MB of memory. (These days, you get spam messages bigger than that…) This required a lot of power at the time. A couple significant technologies first used in the 12C not only helped extend the device’s battery life and technically makes it the grand-daddy of most modern portable tech: The 12C was the first device to employ an LCD screen (as opposed to battery-burning LEDs of the day); it used CMOS technology on the circuit board; and then there’s the small matter of the chip inside the calculator helping run the show. Dennis explains the importance of R2D2 – and no, he’s not talking about Star Wars: “R2D2 was ROM, RAM, and display driver all combined into one chip.  It was the major contributor in cutting down on the number of components, contributing to quality and decreased power consumption.”


Royalty amongst number crunchers. I ask Dennis if he’s ever been recognized for his work - a bit of a cult star on the calculator circuit. And he starts to tell me about when…you know, maybe it’s best to get this story in his words….


In short, the 12C eventually became the gold standard, a staple for an executive’s desk set. It’s also one of only two calculator models allowed to be used in the Chartered Financial Analyst Exam. And it gets special treatment with a commemorative 30th Anniversary Edition. As Dennis soaks in the surroundings of Bill’s office he can’t help but smile a little -- and get a little choked up. (I just had to share this below clip with you as well).



We had a great time chatting that day and if you're curious to learn more, you should check out this link -- and find another video we put together around the anniversary of the HP-12C.

What about you? Do you have any fond financial calculation stories to share? Let me just throw it out there: “What was the most memorable situation where you used the 12C?”




Darren Gladstone

Darren Gladstone (@Gizmogladstone) is a former journalist, now TNB's Blogger-in-Chief. He geeks out over games, gadgets and hot laptops.


by dplatnyc
on ‎09-01-2011 05:41 AM

I remember being given one on the first day of my first real job, in the financial economics group at Goldman Sachs, almost exactly twenty-five years ago.  I was warned, "Don't lose it.  These things are like gold here!"

by Tuzz
‎09-01-2011 08:03 AM - edited ‎09-01-2011 08:06 AM

As a young Test and Measurement Sales rep for HP in 1981, I purchased a 12C as soon as they became available.  I still have and use that original 12C today.  What a legacy the 12C is to the Spirit of what Bill and Dave were all about.  I'm still a  member of the hp family after the 2007 early retiree program.  Today I sell hp as an hp business partner. I look back with pride on the company Bill and Dave built each time I press the keys of my trusty 12C.  Hoping we can bring back that "Spirit of a Startup" now!

by trevor1964
on ‎09-07-2011 07:21 AM

What do you mean 30 years ago?  Mine is sat right here in front of me and I use it every working day!  I use it so much when my daughter hands me her 'normal' calculator I can't perform the simplest of calculations on hers!  MIne's got to be 20+ years old now.  I remember I lost my first one back in the '80s and I was so lost without it so when one of my then colleagues needed a fax machine for his home office I swapped my fax machine for 'his' 12C...yep I've got an iphone, goodness knows how many email addresses, am on LinkedIn, Twitter and surrounded by all the usual guff that we seem to think is so important these days but my 12C is the absolute number 1 must for me and I quite literally could not to my job without it.  If ever there was a poll in the financial markets of the most influential inventions over the last 50 years then for me the 12C would be number 1.  I can still make money without a computer,  not so sure I could without my 12C and certainly don't want to find out.  Hands off, it's mine!!!

by unclebill
on ‎09-14-2011 09:08 AM


Got mine in '83 and I think only changed the batteries once or twice. Is that possible? Won a leather case in a 12-C class and wondered if HP will be selling any accessories? Interested in the anniversary edition but can't seem to find what the improvements might be. Thanks.

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