Hewlett-Packard HP-45 Handheld Electronic Calculator

The HP-45, the successor to Hewlett-Packard’s HP-35 calculator, was also designed for scientific calculations. It has a black plastic case. Like the HP-35, it has a total of thirty-five square or rectangular plastic keys. These include ten digit keys, a decimal point key, and a summation key, all colored light gray. The four arithmetic function keys are left of the digit keys. Immediately above the digit keys are a relatively long enter key, a change sign key, an enter exponent key, and a clear x key. Above these are keys for exchange, roll down, store, recall, and percentage. Above these is a row of keys for squares, conversion to polar coordinates, and trigonometric functions. The top row of function keys is for inverses, logarithms, exponents, and fixing the output as decimal (rather than scientific) notation. A gold shift key in the upper left corner shifts the meaning of many of the keys to functions indicated in gold. In the bottom row, for example, the key for 0 becomes a key that shows the last value of x, the key for the decimal point becomes the number pi, and the key for summation becomes a key for decrement summation.
Behind the keyboard are an on/off switch and a fifteen-character red LED display. This shows the mantissa sign, a ten-digit mantissa, a decimal point, the exponent sign and a two-digit exponent.
A mark on the front edge of the calculator reads: hp HEWLETT•PACKARD 45.
The back of the calculator has a plug for a three-prong power adapter, a sticker reading: PROPERTY OF (/) HAL B. BECKER, a compartment for a battery pack and four rubber feet. Another sticker reads: HEWLETT-PACKARD HP-45 INSTRUCTIONS. Text below the sticker reads: HEWLETT-PACKARD (/) 3.75V 500MW (/) MADE IN USA PATENT PENDING. A sticker inside the battery pack reads: HEWLETT-PACKARD (/) SER.NO. 1349A 37972. The letter A in the serial number indicates the calculator was made in the United States. The first four digits of the serial number suggest it was made in the forty-ninth week of 1973.
Like the HP-35, the HP-45 performed calculations using reverse Polish notation.
Stored with the calculator are a power adopter (2004.3053.02) a leather case (2004.3053.03), an owner’s manual (2004.3053.06), a quick reference guide (2004.3053.05), and an envelope with warranty, payment check, and receipt (2004.3053.07). These all fit in a gray molded plastic case (2004.3053.04).
The HP-45 calculator sold from 1973 until 1975. This example was purchased in December of 1973 for $410 (including shipping).
The donor, Hal Becker of Phoenix, purchased this calculator while working on computer data communication systems with Honeywell.
W.A.C. Mier-Jedrzejowicz, A Guide to HP Handheld Calculators and Computers , Tustin, California: Wilson/Burnett Publishing, 1997, pp. 41–42, 123
David G. Hicks, The Museum of HP Calculators, http://www.hpmuseum.org/, accessed July, 2014.
Accession file.
Currently not on view
Object Name
electronic calculator
date made
Hewlett-Packard Company
Physical Description
plastic (keys; case; display cover material)
metal (circuitry material)
ceramic (display circuit board material)
paper (stickers material)
overall: 1 1/4 in x 3 in x 5 5/8 in; 3.175 cm x 7.62 cm x 14.2875 cm
place made
United States
ID Number
nonaccession number
catalog number
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History, Kenneth E. Behring Center


Add a comment about this object