HP 11C

My 1985 HP-11c is probably on its 4th set of batteries now. Would love a 15c but have the Retro 15C and Free42 emulators on my iPhone now.

I bought a 35s and found the ergonomics not as good as my old, dead 11C. So I bought an antique 15C on eBay, and it sits right by my keyboard all day. I'll use the built in calc in macOS Spotlight for many things, but plenty of times each day I use the HP. Example: yesterday I calculated an angle in degrees by reading off approximate x, y coordinates from a graph on my screen. Swapping windows to a calculator app, repositioning them to see both at the same time, just too fiddly, and clicking the calc app moves the cursor so I have to remember the numbers as I switch context.. The physical HP in front of me leaves my screen undisturbed. Easy.

Back in my school days, I found that TI's calculators had crap keyboards that inevitably failed at the worst moment. I decided to try an HP instead (HP-11C in my case), and I still have that calculator. It still works beautifully, but these days I just fire up Free42 on my phone.

Yes, that series is really good. The calcs I use most often: * HP-25 (yes, a nearly 50-year old calculator, but you can hold it in one hand and it does most things I need very well) * HP-11C or 15C (doesn't matter which, I don't use the extra features of the 15C) * HP-12C * HP-50G (very useful for unit conversions)

Sadly, the keys of the previous "HP15C Limited Edition", which I bought in 2012 - https://www.amazon.com/gp/product/B005EIG3MW - were also crap. My original HP11C (from around its launch date in 1981) works as well or better at this point.