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Hewlett-Packard HP 12C (Voyager 1.0)

Hewlett-Packard HP 12C

The Hewlett-Packard HP 12C is a finance calculator with 10 digits precision and RPN (reverse polish notation) logic. It has 84 functions, 39 keys, and an LCD (liquid crystal) display. The power source is 3x1.5V cell. The calculator was manufactured in Malaysia. The classic financial calculator from HP. Several versions have been produced including Platinum and Platinum 25th Anniversary Edition - still available.​ A sample of this calculator is held in the collection.

Facts at a glance:

Display typeLCD
Power Source3x1.5V cell
Original price$100
Year introduced1981
Current price

User Manual

You can download the Hewlett-Packard HP 12C manual from the manuals website. If this doesn't work, you can also try this alternative download link.


Note that diagnostic tests generally delete any data on the calculator. Be sure to back up any important information held in the calculator before running these tests.

Turn calculator off, press and hold X (multiply) key and then press ON key, then release X key. Display will show "running" for about 20 seconds, and if tests pass, all display elements will be on. Press any key to exit test. For keypad test, use divide key instead of X key, and then press each key in turn (will show "Error 9" if out of sequence).


If you have a Hewlett-Packard HP 12C that is no longer working, you can first try replacing the 3x1.5V cell batteries. If that doesn't solve the problem, then a repair might be possible, although you have to weigh up the costs against just buying a new one, as this model is still currently available.

See other calculators by Hewlett-Packard