I'm a bit of a calculator geek. My favourite calculator is the HP-15C, an advanced scientific programmable RPN calculator made in the 1980s. It's got a distinctive form factor:



I bought mine in 1987 and it got me through university, and still runs on the same set of batteries it came with 23 years ago. The HP-12C financial version of this calculator did so well that it continues to be sold to this day.

These days it's a bit awkward to actually carry a calculator around (since there are computers everywhere), so I've implemented a (nearly complete) simulator for the HP-15C in Javascript. You can find it at http://hp15c.com along with some more information about its capabilities and current known issues.

If you're unfamiliar with this calculator, you can find a scanned copy of the Owner's Handbook (and the Advanced Functions Handbook) online. There is even a Petition to Bring Back the 15C that you can sign.

If you've ever used this calculator, or one like it, I hope you find this simulator entertaining. Feedback, bug reports, and even contributions are welcome!