Priced at $395, roughly $2,900 today, the HP-35 could perform logarithmic and trigonometric functions that had previously required a slide rule or bulky desktop machine. Engineers and scientists adopted it rapidly, and within a few years the slide rule, a tool of engineering education for generations, effectively vanished from classrooms and drafting tables worldwide.
Bill Hewlett reportedly set the project in motion after asking his engineers to design a scientific calculator small enough to fit in his shirt pocket, a challenge that at the time seemed almost absurd given the size of existing electronic calculators. The team, initially skeptical it was possible, spent about two years cramming complex trigonometric and logarithmic algorithms into a device weighing just nine ounces.
HP had never sold a consumer product before and worried the calculator's price, nearly ten times that of basic four-function calculators, would doom it. Instead, engineers and scientists snapped it up so fast that HP struggled to keep up with demand. The HP-35 used reverse Polish notation for its calculations, a quirky input method that generations of engineers came to love or hate, and it is widely credited with killing off the slide rule as a serious engineering tool within just a few years of its release.
Key people: William Hewlett