Seems like there's no thread comparing scientific calculators. That was one of my first priorities upon getting my droid X. Here are some notes on some I tried. But first, my criteria--I was looking for: Most commonly used functions on a single screen Multi-line display showing calculation and result. Complex numbers would be great, but not essential...since none of the first ones I found do that, I'll save ones that do that for another post Mathdroid, my favorite so far. Has a numpad and basic operators on the bottom, the 5 most recent calculations at the top (and you can scroll back for more), and two rows of scientific buttons in the middle. My only complaint is that there are two sets of those buttons and a toggle button to switch sets. I constantly need to switch, as pi is in the secondary set, whereas trig, log, ^ and sqrt are in the main set. There are additional functions, such as, for example, BitShiftRight, that you can get by typing on the keyboard, but that aren't available with buttons. You can also assign values to variable names, (e.g. a=12) using the keyboard. No graphing, solving equations, etc. HandyCalc This seems very popular and with good reason. Nice interface and powerful. Has all the bells and whistles, like graphing, solving equations, etc. The main screen has the number pad plus x^2, and sqrt, and EE (exponential notation); a "shift" button gets you to all the usual scienfitic stuff, like pi, trig, and x^y. That doesn't quite satisfy my ideal that it have everything on one screen, but it's close. After you hit pi, for example, on the "shift" screen, it automatically goes back to the numpad screen (for better or worse...probably better). One thing I really like is that it displays what you enter in real math notation, for example a symbol for pi instead of the letters p and i, and exponentiation using superscripts rather than ^. CalcBuddy Pretty nice. If you are entering a long expression, it displays the result so far before you hit enter--e.g., if you enter 5x5x5, it will display 25 when you've gotten as far as 5x5. Sadly for me, the commonly used buttons are spread over three pages, and I'm not going to want to keep moving between them. Otherwise very nice, although the instant-result feature takes a little getting used to. Stock Calculator on my Droid X. Just for reference--it has trig, pi, e, ^, ! and sqrt, but to get those you need to select the "advanced panel" from the menu, at which point the numpad goes away. Ridiculous--useful only in a pinch or for basic calculations. Calc+ There's a free and a paid version. I tried only the free. This has an attractive screen with colors that remind me of my dad's 1973 TI SR-10. And in landscape mode, it has most of the frequently-used buttons on one screen. Sadly though, it's missing input in exponential notation, the feature that prompted my dad to spend $100+ on the SR-10. It's also missing multiple-line display, and it doesn't even display the whole calculation on one line as you enter it--if you enter 1+2=, the 1 disappears from the screen when you hit +. Paid version adds unit conversions. Uninstalled. HowlCalc_lite This looked good but I lost interest when I tried to calculate 10^2 by typing 10 then hitting the "^2" key. It displayed 10pow2(. Apparently I'm supposed to hit the ^2 button and then 10. When I do that, it displays pow2(10, and I can hit return and get 100, without ). But I have no interest in learning its quirks when there are better options. Uninstalled.

So far I've found only two that do complex numbers: Arity and MathPac. Arity is free, and has cool 3D graphics. I hadn't tried it because if I want to do 3D graphics, I probably want to work on my desktop not my phone, but now that I see it does complex numbers, I'll try it. Mathpac is $14.99, so I'll have to schedule my download of it when I have time to try it and see if it's worth that.

RealCalc is nice too, may not be as advanced as some of the above mentioned, but it's pretty powerful and smooth.

Have you tried: All-in-1-Calc Free - Android app on AppBrain ? Click the menu key and you can use it for currency, trigonometry, and other features.

My favorite is Droid48 - Android app on AppBrain It's RPN (a necessity) and emulates the actual calculator. I own one and can attest to its accuracy. Of course it's effing hard to adjust to if you aren't into RPN and it's extremely complex.

Test your favorite calculator 100-99.9=0.1 or 100-99.9=0.0999999999 (calculating of my stock calculator) Harry

Thanks for the pointers to realcalc and all-in-one calc. I tried both and neither makes my top list. Here's why: Realcalc: Nice keyboard with all the key stuff right there on the main screen. Downside is that it's a single-line display that doesn't even show one full calculation. By that I mean if you type 2+3=, the two goes away as soon as you press 3, so you never see "2+3" on the screen. It's better than some in that when you press +, the 2 stays there and a little "+" is shown to the left, but ever since my ~1980 Sharp EL-5100s, I've gotten used to seeing "2+3" when that's what I calculate and it's hard to go back. All-in-one calc: same complaint, only it's worse, because if you type "2+3" you don't get any visual feedback that you've hit the "+" key correctly--you just see the two until that goes away when you hit 3. Plus, you need to swipe to the advanced function screen to get y^x or trig functions, and you have to pay extra to get rid of ads.

This doesn't really count as a scientific calculator, but Wolfram Alpha has a very nice (2 or 3$) app available. It requires a data connection, but whatever computer is actually doing the calculations you put in is a hell of a lot more powerful than a cell phone.

i also like RealCalc but good thing that i've been hearing other opinions here. thanks to all of you. Alton A. Clark Licensed clinical social worker Welcome to Integration Calculator

I have to second this recommendation. Easy to use on the go if you have a "real" calculator for more complicated work while sitting down at the office.

I would like to recommend PG Calculator. It comes in free different versions: Free, Standard and Pro. Pro version can work with complex numbers. The app has nice interface which can be changed using different skins. It can work in both Algebraic and RPN (Reverse Polish Notation) modes. Algebraic mode allows to process the mathematical expressions. Calculator has a library of common mathematical and physical constants and allows for user-defined variables. Pro version has the Time Value of Money solver and also the IP Subnet calculator.

Personally I love realcalc, does what i need perfectly. Some of the others mentioned in the OP have more features (handycalc is pretty good), but generally if i need that sort of thing i'll be using a spreadsheet on a PC.

There are a bunch of new ones out there. Many are equivalent to others that have been mentioned here, and have at least one of the same limitations, so I'm not going to try to list them all, but I am excited about: Scientific Calculator by Rohan Laishram. Free, multi-line display, most keys needed on one page, does complex numbers. Partially making up for the lack of a multi-line display is that it's easy to call up a history from the menu key. Scientific Calculator by BiShiNews. Free, clean look, most keys needed on one page, no multi-line display; no complex numbers Math Pac. $15, multi-line display, most keys needed on one page, does complex numbers. Lots of other capabilities, and more advanced versions also available, but do you really want all of that on a phone, not your PC? Scientific Calculator by roaming squirrel Free, most keys needed on one page, no multi-line display; no complex numbers Algeo graphing calculator Free, simple and clean but has a multi-line display and exactly the keys I need most on the main page. Might not work as well for you. My only complaint is that it uses * as a symbol for multiplication--I prefer x or a centered dot. But that's getting very picky! Cube Calculator Very nice but does require flipping to another page for most scientific functions and variables. Looks like I'll be trying BiShiNews, Rohan Laishram, and Algeo to choose my new favorite...Math Pac looks nice too but since I wouldn't use most of its features, why spend $15, even though that's still pretty inexpensive.

Check new calculator: Calculator++ It is supposed to be the BEST calculator in android.market. Thread about this application

Thanks for the various comments above on calculators. I'm about to buy a Droid Charge (Verizon), switching from a Palm Treo. The Treos had an excellent calculator, spread over multiple screens. trig (including hyperbolic), financial, logic, conversions- weight, length, area, volume (metric and cooking measures!!), math with logs and powers. Is there any single calculator that has all of these? Or- what would you suggest to cover these with more than one calculator.

That sounds a lot like NeoCal Advanced, right down to the multiple screens (which you swipe between). Only catch is, these days the refund period for paid apps is very short, so you don't get long to decide. For an all-on-one-screen calculator I've used RealCalc for a long time - does have some conversions, but that's never been one of my requirements so I can't comment on how comprehensive those are.