Hewlett-Packard HP-65 Handheld Electronic Calculator

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This programmable scientific handheld electronic calculator was Hewlett-Packard’s third model of a handheld scientific calculator (after the HP-35 and HP-45), and its first programmable handheld calculator. Hewlett-Packard staff dubbed it a “personal computer.”
The gray plastic case holds a keyboard with thirty-five keys at the front, two switches, and a display. The keys are square or rectangular on top and slope downward at the front. Many of them may take on three meanings. One is shown on the top of the key, in black or white, one shown on the sloping front of the key in blue, and the third shown in gold behind the key on the keyboard.
The lower part of the keyboard includes data entry keys for ten digits; as well as decimal point, enter, enter exponent, and clear display keys. It also has keys for the four arithmetic operations. Pressing the R/S (run/stop) key in the bottom right corner begins program execution.
Above this set of keys are prefix keys (function, inverse function, store, recall, a second function) which are followed by other keystrokes to complete a command. Above these are five keys for programming – DSP (to format the display), GTO (go to), LBL (label), RTN (return) and SST (single step). Above this are five lettered keys that stand for user-definable functions or subroutines. Behind the keyboard are the on/off switch and a second switch that may be set for writing programs or for running them.
Behind the keyboard is a red LED display for up to ten significant digits, plus two-digit exponent and appropriate signs for both.
The HP-65 was specifically designed to assist in repeated calculations required in such disciplines as science, engineering, finance, statistics, mathematics, navigation, medicine, and surveying. Toward that end, it contained a small magnetic card reader and recorder. Users who had worked out a series of commands they wished to reuse could save the program to a magnetic card. The cards are 7.2 cm. w. x 1.1 cm. d. and made out of mylar coated with a layer of ferric oxide. Programs could have up to one hundred steps. A variety of prewritten programs were available for purchase.
The back of the calculator has an outlet for a power adapter, a battery case, and a sticker that reads in part: HEWLETT-PACKARD HP-65 USER AIDS. A sticker below this one reads: HEWLETT•PACKARD (/) SER. NO. 1608S 02068. The first four digits of the serial number indicate that the calculator was made in the eighth week (March) of 1976. The S signifies manufacture in Singapore.
The calculator has a battery charger and AC adapter, as well as a battery pack that holds three batteries (the batteries were decaying and discarded). A transparent plastic box labeled “STANDARD PAC” contains forty magnetic cards. Nineteen of these are fixed programming cards, one is for cleaning, and the remaining cards for programs by the user. The spiral-bound HP-65 Quick Reference Guide is copyrighted 1974. Also part of the object is a metal security cradle that can be taped or screwed to a desk or other stand. It also could be held via a security cord. The calculator cord (and the security cord, if it was used) were set in holes in the back of cradle and the cradle then locked with a key, making theft more difficult. The cradle is in a box with screws, tape, the security cord, and paper instructions.
The HP-65 sold for $795.
Chung C. Tung, “The ‘Personal Computer’: A Fully Programmable Pocket Calculator,” Hewlett-Packard Journal, May 1974, pp. 2–7. Further articles in this issue of the journal discuss other aspects of the HP-65 calculator.
W.A.C. Mier-Jedrzejowicz, A Guide to HP Handheld Calculators and Computers , Tustin, California: Wilson/Burnett Publishing, 1997, pp. 42–44, 132.
David G. Hicks, The Museum of HP Calculators, http://www.hpmuseum.org/, accessed July, 2014.
Currently not on view
date made
Hewlett-Packard Company
place made
Physical Description
plastic (case; keys; display cover; battery holder; program pack holder; security cradle material)
metal (circuitry; keys (for locking) material)
paper (stickers; instructions; box for security cradle material)
ceramic (display circuit board material)
overall: 7 cm x 22 cm x 21 cm; 2 3/4 in x 8 21/32 in x 8 9/32 in
ID Number
accession number
catalog number
Credit Line
Gift of Jon B. Eklund
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History


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