The world’s first handheld scientific calculator

On February 1, 1972 — just a day before a year was completed from the official go-ahead for the product — HP-35 was made available to the world. Now recognised as the world’s first scientific pocket calculator, the gadget revolutionised the way we looked at handheld equipment. A.S.Ganesh punches some keys to give you the tale of these number crunchers…

What’s the one thing that you — or the elders with you in case you haven’t got your own yet — make sure you carry with you every time you step out of the house? For nine out of ten of us (or maybe even a larger percentage), the answer will likely be our smartphones. Ubiquitous and useful — though there’s no denying their pitfalls — these devices are at the forefront of personal tech at the moment. 

The HP-35, a handheld scientific calculator, paved the way and served as a precursor for most of the personal tech devices that we employ on an everyday basis today. But before we head to how the HP-35 came to be, we will first have to look at the 9100 programmable calculator that came from the same stable. 

The stable, or company, that we are talking about here is the Hewlett-Packard, started by two Stanford University graduates, Bill Hewlett and Dave Packard. Founded in 1939, HP grew into a Fortune 500 company with about 9,000 employees by the mid-1960s.

An original HP calculator on HP founder Bill Hewlett’s desk. | Photo Credit: Robert Scoble / flickr

It was under these circumstances that Tom Osborne, an American engineer, brought the Green Machine — an electronic calculator that he had built — to Hewlett in 1965. Even though the Green Machine couldn’t do transcendentals (sine, cosine, tangent, etc.), Osborne said it could when questioned about it. Hewlett was impressed with what he saw and brought on Osborne as a consultant to turn the Green Machine into an actual calculator. 

What started as a six-week consultancy turned into six months, then a year, and then another. Working alongside HP engineer Dave Cochran, Osborne finished the typewriter-sized 9100 programmable calculator early in 1968.