HP 35S/B12 Scientific Calculator, Black

Despite having a couple of HP calculator emulations on my iPhone, it somehow isn't the same. My "every day" calculator (HP 42s) was beginning to play up, getting increasingly difficult yo read the display, so time for a new one. In general the HP35s is better in nearly every way – particularly in flexibility and ease of use, and it is AMAZING value – I paid over £100 for my HP42s over 30 years ago!There are only a couple of niggles; conversion from litres to gallons (and back) is in US gallons only. This is mildly irritating as we buy petrol in litres, but then work out mileage in miles per gallon. It isn't a difficult calculation, but having it teasingly built in is annoying.My only other complaint is that I wish it was built to the same standard of HP calculators from the 1970s and 80s, it just feels a bit plasticy. I would happily pay more for better plastics and an olde style soft click of the buttons of yesteryear.As to RPN, it is clearly better, easier, more efficient, more logical and elegant than algebraic entry (as 100% of people who know and use RPN will agree), but for those too timid to dip their toes in the RPN pool, it can work algebraically too.

Superb HP RPN (Reverse Polish Notation) calculator. Fully programmable, in fact that's the main point of it. Can be used as a standard scientific calculator, but you'll have to learn to use RPN as this is not an algebraic calculator. You want to find the Sine of 45 degrees, you need to type 45 then hit Sin. You want to do the squareroot of (123+343-32) you press 123, enter, 343, add, 32, subtract, squareroot. You don't use brackets with RPN, it's quicker with complex embedded problems, when you have invested a couple of hours to really get used to it. Wonderful HP manuals available for download. Enjoy learning this powerful beast. Understated. You feel like you are programming something from 1983, which is part of the nostalgic joy of HP calculators. Thank goodness they still make them. A calculator with soul for those with a brain.

I really like this calculator, it does a lot and is easy to use. Good value too, for what it is able to do. The only reason I am not giving it the full 5 stars is the build quality, which is not comparable with my old HP calculators. It feels cheaper and lights and you do need to check the keys when you receive this item, because sometimes some or more keys are not as responsive as they should be. I have only had this calculator for about a year, so I cannot say whether it will last as long as other HP calculators, but I suspect it may not.Still more than happy to recommend it for those who would like to learn using RPN, which I still think is by far the superior method for solving problems on a calculator.

This takes me back to the days of my first programmable calculator, the HP41CV, with very similar looks and the same sturdy feel to it. It should be noted that the conversion factors for, say, litres to gallons is a conversion to US gallons (=3.785 litres as opposed to 4.554 litres to the Imperial gallon) so care should be taken there. I can't see a way to change this. No matter, I shall now enjoy relearning the programming process, though the HP manual, otherwise very good, is not that clear on how to programme. I am glad that I have the experience gained with the 41CV.That said the HP35s represents very good value and highly recommended.Howard McClellan

HP caculators are often thinngs of beauty! I've missed the boat on owning a real 15C or 16C, but this calculator does everything its illustrious predecessors did and more. OK, so it's portrait mode rather than landscape, but that's the only down side. On the positives, it supports intuitive RPN as you might expect, but also algebraic notation for those who hanker after an = key. It has loads of scientific constants built in, does basic conversions, supports hex arithmetic & logic, fractions, programmable...Great calculator, and great service from Science Studio who rapidly got a replacement to me when Royal Mail lost the original!Can't imagine I'll ever find a beter calculator (unless they make a landscape version!)

Excellent retro-style calculator with the advantage of Reverse Polish Notation as well as algebraic entry. The feel of the keys on this version is not quite as solid as the original HP calculators, but is still far better than most.Programmability is useful for repeated tasks, although you would probably use a PC for statistical work. Great for engineering calculations on the move if a laptop is not appropriate, all the functions you are likely to want and more. Now supplied with a slip sleeve rather than a zip pouch (the zips never worked properly). The comprehensive manual is now on CD but is downloadable to e-reader, so is still usable as a reference or passtime if travelling. A good all-round buy for anyone who makes heavy use of a scientific calculator.

HP RPN calculators is for the ones that know what RPN is and what it’s unmatched benefits. If you are not even curious about it stop reading this and pick the Casio Fx991 in your country/language (in your local supermarket may be way cheaper than Amazon, in my country is half prize).If you are at least curious about RPN...RPN means Reverse Polish Notation and is a faster and more secure way of introducing data once you master it. The test I made with my Kid was to made this the first calculator, learned how to use it and now (1 week after) says it’s faster than classmates’ ones (non RPN). Luckily is not the only one in class so bullying is not a big issue (kids are mean to other kids and any difference is an opportunity o pick on.For a simple RPN is good, key press is reassuring (not like Casio above), it is a good one but not cheap. It should last more than the others (e.g Casio).If you are an HP calculator fanboy (not me) just buy because it is the 35th anniversary model.I bought it because was the simpler/cheaper quality HP RPN I could buy (no need for graphic and matrix and algebraic solving for now)