HP introduced the 12C on September 1, 1981, and it has been on sale ever since. Wikipedia calls it HP's longest-running and best-selling product, and it's the de facto standard calculator in finance. That long run means the used market is full of 12Cs that look alike but aren't. Some take button cells and some take coin cells, some do only RPN and some do algebraic entry too, and a few are special editions. This guide walks through each one, what's different about it and which to buy.
The short answer
For the CFA exam, any 12C works. The CFA Institute's calculator policy, updated in January 2026, allows only two models in the exam room: the TI BA II Plus (including the Professional) and the HP 12C, including the 12C Platinum, the 12C Platinum 25th Anniversary Edition, the 12C 30th Anniversary Edition and the 12C Prestige. If you already know RPN, or want to learn it, buy an original 12C. If you've only used algebraic calculators and want to be productive on day one, buy a 12C Platinum, which does both. Buy the special editions because you want them, not for the exam.
The original 12C, and why its battery matters
The 12C puts time value of money on the top row: N, i, PV, PMT and FV. You enter the numbers you know and press the key for the one you want. It holds up to 99 program lines and 20 storage registers, and it handles 20 cash flows. The financial math inside came from William Kahan and Roy Martin, whose work HP described in HP Journal in 1977.
What changed over forty years is mostly invisible. Wikipedia counts many hardware revisions, and the battery door is the easiest way to tell them apart:
- 1981 to 2001: three LR44 or SR44 button cells and HP's original chip. A flashing asterisk in the lower left of the display warns you the batteries are low.
- From 2001: one CR2032 coin cell and a new processor.
- From 2008: two CR2032 cells in parallel and an ARM chip running the original firmware, 60 to 90 times faster on most benchmarks. A battery symbol replaces the asterisk.
- From 2015: a newer ARM chip, with Rev 2 on the bottom plate.
- From 2022: no Hewlett-Packard on the front plate and a screw in the battery door, built by HP's licensees.
The slow original chip was a choice. Wikipedia reports that HP's market research in the late 1980s found users didn't trust results that came back too quickly. For exam work speed doesn't matter, since the calculator finishes a TVM problem long before you've read the next question. On a two-cell unit, swap the batteries one at a time so the memory survives.
Because the 12C is still sold new by HP's licensee Moravia, a used one makes sense when it costs clearly less than new or when you want an older build. A clean 1980s 12C with button cells is the one collectors like. The checks are simple: a battery compartment with no leaked crust, a display with every digit complete, and keys that register once per press.
The 12C Platinum
The Platinum arrived in 2003 and is still made. It keeps the 12C's layout and adds what people asked for. It takes RPN or algebraic entry, with a key for each mode. It holds up to 400 program steps against the original's 99, it has 20 storage registers, and it handles 30 cash flows. HP claimed up to six times the speed of the original. Kinpo builds it for HP.
In 2005 HP revised it: parentheses on the blue-shifted STO and RCL keys, an undo key and room for 80 cash flows. So if you want parentheses in algebraic mode, look for blue parentheses over STO and RCL in the listing photos. Depending on the version it takes one or two CR2032 cells.
Two things catch 12C users out. Its change-sign key behaves differently in RPN mode, and LAST X moved from the ENTER key to the plus key to make room for equals. Collector Tony Thimet also finds its keys a little more plastic than the older 12C's. None of that matters if you're learning on it. You'll spot a Platinum in photos by its silver upper plate, where the 12C's is gold.
The 12C Platinum 25th Anniversary Edition
In 2006 HP marked twenty-five years of the 12C with a limited edition, and it chose the Platinum to do it. Underneath, the 25th Anniversary Edition is a Platinum of the 2005 kind, with parentheses, the faster GPLB31A processor, and both RPN and algebraic modes. A listing photographed in algebraic mode is normal for this model. Wikipedia says its limited supply was enough for Victor to launch the V12 look-alike in 2007. It's exam-legal, and the CFA policy names it. We couldn't find a reliable description of its commemorative markings, so ask the seller for clear photos of the front, the back and the box.
The 12C Prestige
The 12C Prestige, HP part F2233A, came out in 2008. It's a Platinum of the 2007 kind dressed in the original 12C's gold-colored plate. So you get the classic look with the Platinum's RPN and algebraic modes, 400 program steps and 30 cash flows. HP Brazil's product page lists exactly those features.
The Prestige is often confused with the 30th Anniversary Edition, and this site's earlier version mixed them up too. They're separate products. The quick tell is the ALG key: the Prestige has one, and a plain gold-plate 12C doesn't.
The 12C 30th Anniversary Edition
In 2011 HP released a 30th Anniversary Edition, part NW258AA, alongside the 15C Limited Edition. Wikipedia says only 40,000 were made. It's built on the 2008 ARM version of the original 12C, so it's RPN only, with 99 program lines. We don't have a separate page for it, since we couldn't source enough about it, and it's covered on the 12C page. The CFA Institute names it, so it's exam-legal too.
What about the HP 17BII?
The 17BII is HP's 1990 business calculator, and it's a good one: RPN or algebraic, menus for time value of money, cash flows, bonds and depreciation, a two-line display and an equation solver. It isn't a 12C, though, and the CFA Institute doesn't allow it. If the exam is why you're buying, skip it. The Society of Actuaries allows no HP calculators at all, so for actuarial exams you'll need one of TI's approved models.
Clones and look-alikes
The 12C's popularity attracted copies. Wikipedia lists the Victor V12, the BrtC FC-12, the Compucessory CCS28956, the Procalc FN 1200C, the Truly SC123 and the Aurora FN1000, and SwissMicros makes the DM12 family with a dot-matrix display. None is an HP 12C, and the CFA policy allows only the HP and TI models it names. In the listing photos, look for HP branding, the gold or silver plate and HP's layout. Ask if any of it is unclear.
Checks for any 12C
- Battery compartment: ask for a photo with the door off. Clean contacts with no crust are what you want, and the cells tell you the era.
- Display: ask for a photo showing 0.00. Every digit should be complete and even.
- Keys: ask whether every key registers once per press, including the gold f and blue g shifts.
- Model: check the plate color and the keys. Gold with no ALG key is a 12C; silver is a Platinum; gold with ALG is a Prestige.
Not sure RPN is for you? RPN in one hour walks through it on a 12C, and our CFA exam page lists every 12C we cover.
