HP 15C Calculator 4+

I own an old HP12 and am committed to RPN so I am delighted with this App.
I do have a problem with “landscape lock” which I think works fine if I have my iPhone free to rotate, but I keep my iPhone in portrait mode. HP15c landscape lock works if I select that first and then set my iPhone to portrait, but after sleep it goes back to HP15c portrait. Fiddly!
With such a high-class emulation, it is a shame for a detail to let it down.

This is HP at its best. HP engineers created these unique RPN calculators. They are literally unique since no other major manufacturer used or uses RPN, thinking their customers are too lazy or unintelligent to learn how to use it. HP should be rewarded for creating the 15C and 12C apps. These are iconic brilliant tools worthy of their place in the pantheon of innovative human calculating machines. The manual alone is a gem, included in the app. HP wrote the best instruction manuals of any company around. Each example function illustrated by a real world computation based on physics or business needs, is literally a pleasure to read and work through. These are so easy to program you can get genuine time saving use out of these calculators. The real world versions are 10 times or more the cost of these apps. So stop complaining about cost and enjoy. Thank you HP.

I was given an HP11C about 30 years ago whilst at college. Whilst RPN takes a bit of getting used to once I got comfortable with it the ease of completing complex calculations is extraordinary.

I still have that 11C but these days I keep it safe at home. I was so pleased to find that I could replicate it, plus a few extras, with this app. Even better, you get the manual as well which I have long since misplaced.

For me, they are the best calculators ever made by a some margin!