HP released their first few handheld calculators with model numbers like the HP-35 and HP-80. These models looked the same but had different features as one is a technical calculator and the other is a business calculator. It did not take long before other HP calculators were released. There were models that came out like their small desktop calculator with built-in printer and the smaller handhelds. HP was expanding their calculator production until there were too many models to remember. To make it convenient and easy to remember, HP decided to classify their calculators into a “family” or a series.
Here are the Families and Series Names of different HP calculator models:
This family consists of the first few handheld calculators like the HP-35 which is the first handheld HP scientific calculator. Then there is the HP-80 (first HP business calculator), HP-65 (first programmable handheld), HP-45, HP-70, and HP-55.
Classic Printers (Printing Desktop Calculators)
This family consists of desktop calculators with built-in printers. The HP calculator models under this series are the HP-46 and HP-81. These two models are the printing versions of the HP-45 and HP-80. The HP-81 was considered a top-of-the-line desktop printing calculator because HP added more functions to it.
Woodstock (Second Generation Handheld Calculators)
This family consists of the second generation series of handheld HP calculators like the HP-21 (second generation HP-35) HP-22, HP-25, HP-25C (HP-25 with continuous memory), HP-27 (the “Do Everyting” model with sci/stat/bus/math functions), and HP-29C (high end programmable).
Topcat (Second Generation Desktop Calculator)
This family consists of top-of-the-line HP desktop calculator models HP-91, HP-92, Hp-97, and HP-97S. These calculators are also known as the 90’s series. This family has a printing scientific calculator, printing business/financial calculator, and I/O calculator.
Spice (Third Generation HP Calculators)
This family is also known as the 30E/C series because the models included in this line of HP calculators are the HP-31E, HP-32E, HP-33E/C, HP-34C (scientific programmable with integration and solve), HP-37E, and HP-38E/C. This series consists of improved HP scientific calculators, statistical, scientific programmable and financial calculators.
This family consists of two handheld calculators, the HP-10 and HP-19C. The HP-10 is a handheld printing adding machine while the HP-19C is a high end programmable calculator. Both are handheld printing machines, the difference is that the HP-10 is a simple adding machine while the HP-19C is an advanced calculator with programmability.
This family has the models HP-41C, HP-41CV, and the HP-41CX. These models are packed with features because they were HP’s solution to the lack of keys and functions on the HP-67. These calculators made it easier to write and use numeric-only programs. It made programming, typing of functions, and keyboard assignments easier for the user.
This family, also known as the 10C series, consists of the HP-10C, HP-11C, HP-12C, HP-15C, and HP-16C. This series has a basic scientific programmable calculator, more advanced scientific programmable, top selling business calculator, scientific with matrix & complex math, and a computer scientist calculator. The calculators in this series look similar to each other but if you look closely, the keys are placed differently for each model.
This family consists of HP calculators that fold, also known as the clamshell series. Models in this family include the HP-18C (business model with solver) and HP-28C/S (scientific with symbolic math and solver). These two totally changed the way HP scientific calculators looked because when you open it you can see the number keys on the right and the letter keys on the left.
This family consists of lower end series models, including those models ending with B (business), S (scientific) and II. Models included in this series are the HP-27S, HP-17N, HP-22S, HP-42S, HP-32S, and the HP-14B. The different types of calculator in this series includes an algebraic do everything calculator, algebraic scientific, algebraic business, and RPN scientific with complex math.
The families here only run up to 1986. There are two other names that can be found in the HP calculator series names, Quake and Pogo. However, it shows that calculators under these families never went into production. Based on the families mentioned, the obvious trend in determining the family of HP calculators depend on how they look, what they can do, and the trend in model names. This makes it easier for consumers (then) and collectors (now) to remember HP calculator models.