Hewlett-Packard 18C Business Consultant  
Written by Accutron on 2016-09-11  

Introduced in 1986 and ending an atypical three-year gap in new calculator development, the Hewlett-Packard 18C Business Consultant represents a significant departure from HP's previous handheld calculators. The HP-18C is the first calculator to be based on HP's proprietary Saturn processor architecture, originally developed for the HP-71B handheld computer. It is also the first HP calculator to be programmed internally in RPL, the first to be equipped with soft menus, and the the first HP calculator with an infrared printer interface. Despite its internal RPL, the HP-18C is not user-programmable, and employs stack-based algebraic operation. The HP-18C is also the first calculator to make use of a popular but flawed clamshell housing, with a left-hand alphabetical keyboard and very few shifted functions.

The HP-18C's clamshell housing was later used in the improved HP-19B financial calculator, as well as the HP-28C and HP-28S programmable scientific calculators. These clamshell models share a critical design flaw which causes the battery hatch to break over a period of time. As a result, used units will typically be found with tape holding the battery door in place.

The HP-18C's key architectural features, including its Saturn processor, RPL programming and soft menus, ultimately evolved into the HP-48 series of graphing calculators.

HP-18C Business Consultant Owner's Manual (PDF)


Hewlett-Packard 18C Business Consultant financial calculator.


HP-18C, enlargement of alphabetical keypad. The HP-18C and other clamshell models have the highest key counts of any HP personal calculator. Unlike the more sophisticated HP-19B and HP-28C/S, most of the keys on the HP-18C lack a shifted function.


HP Personal Calculator Production Timeline (1972-2003)

This article is part of the [Electronic Calculators] exhibit.

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