Our math teachers used to warn us that we wouldn't have a calculator everywhere we go. But now we have smartphones with us everywhere we go, with access to hundreds of calculator apps.

Since there are so many options, it can be hard to nail down the right one for your needs. Today, we're going to break down the best free calculator apps for Android.

1. Calculator (by Google)

This is your simplest, safest bet. Google offers a bare bone, yet well-designed app that will handle basic math tasks, but not much else. It calculates in real time, so you don't even have to reach for the equals button.

You can get some more complex functions by swiping in from the right side, but it's still a rather limited set. The only other major feature is that you can tap at the top of the screen to reveal a three-dot menu that allows you to change decimals to fractions—and that's about it. There's no history or graphing.

It is totally free and has no ads, though, so it gets the job done (unless you're trying to live Google-free).

Download: Calculator by Google (Free)

2. Calculator ++

If the Google Calculator is a little too basic for you, try Calculator ++. This app has both a Simple and an Engineer mode. It supports a wide variety of functions, a history of everything you've calculated, and it can even create graphs.

One neat little feature is swipeable buttons. Swipe up on a button to activate the option on the top part, and swipe down to activate the option on the lower part. It's also customizable, with several theme options available. Along with a widget for your home screen, it includes a floating window mode.

This app does contain ads, but they only display on side pages like History, not the main calculation page. You can remove them for $4. Overall, it strikes a nice balance between simple and functional.

Download: Calculator ++ (Free)

3. ClevCalc

ClevCalc is actually a bunch of calculators all in one. Not only does it have the basics like a currency and unit converter, but it also has everything from a fuel cost calculator to an ovulation calculator.

You can choose from several themes, all inspired by Material Design. Though the app does have ads, you can remove them via an in-app purchase.

Download: ClevCalc (Free)

4. Calculator (by TricolorCat)

Here's a choice simply named Calculator. This one is best for folks who are particular about their keyboard because it has three different layout styles: Standard, Stylish, and Ergonomic.

Related: The 5 Best GIF Keyboards for Texting and Emojis on Android

It also features a ton of different color options and the option to add or remove the memory buttons. Other than that, you can change how decimals appear (1.5 or 1,5) and view your history by swiping down from the top. It's super simple, but also more customizable than most basic calculator apps.

The app does have a banner ad along the bottom, but you can buy the Pro version to remove it.

Download: Calculator (Free)

Download: Calculator Pro ($1.50)

5. CalcTastic Scientific Calculator

This app is for anyone who needs more scientific calculation options. It has a basic calculator too, but the emphasis is on the scientific portion. You can work on complex problems to your heart's content, but it can't graph anything.

It's also nicely customizable, with some classic scientific calculator themes and a plain light theme. If you upgrade to the Pro version for $1, you get seven more themes, polar form complex numbers, landscape support, and a programmer calculator.

Download: Scientific Calculator (Free)

Download: Scientific Calculator Pro ($1)

6. RealCalc Scientific Calculator

Another good scientific calculator is the popular RealCalc. It's designed to look like the traditional hand-held scientific calculators you used in school.

RealCalc has all the standard scientific function you'll need. It also supports history, memories, unit conversions, and constants. Binary, octal, and hexadecimal calculations work just fine too.

The app offers two calculator types, traditional and Reverse Polish Notation (RPN). When using the traditional type, make sure you put parentheses around parts of the equation to preserve calculation order. It's different from the other calculators listed above—you can't just type in the equation as it appears.

You can also choose from a number of display styles and formats to customize the look of the app.

The free version offers many useful features that may be enough for your purposes. If you want more features, like fractions, degrees/minutes/seconds, customizable conversions and constants, landscape mode, and a 12-digit display, you can purchase RealCalc Plus.

Download: RealCalc (Free)

Download: RealCalc Plus ($3.49)

7. CALCU

This app finally brings a somewhat original name (even if it is just a shortened version of "calculator"). CALCU has both basic and scientific layouts, a bunch of slick themes, and even an option for adjusting the font.

It has swift little swiping animations, like swiping down to reveal the history or swiping up to reveal more scientific buttons. There's a banner ad along the top that you can remove via a $2 in-app purchase.

Download: CALCU (Free)

8. All-In-One Calculator

If you simply want a calculator, pure and simple, you may be better served by one of the other apps on this list. But if you want an app that not only offers a smooth and cleanly designed calculator, but also so many other things, this one is for you.

This app can calculate numbers, but also percentage, equations, shapes, speed, temperature, currency, age, and so much more. Chances are, anything that you need calculated can be computed with this app.

Download: All-In-One Calculator (Free, in-app purchases available)

9. Desmos Graphing Calculator

For those who want a dedicated graphing calculator app, Desmos Graphing Calculator is for you. There's not even a basic calculator interface here; it's all about the graphs. The app makes it easy to program in and plot multiple functions, then use sliders to adjust them. You can even start with some of the app's example graphs for some help.

If you want, you can make an account to sign in and sync your graphs. Best of all, there are no ads and no in-app purchases.

Download: Desmos Graphing Calculator (Free)

Which Is the Best Calculator for Android?

Each of these apps has its strengths and weaknesses, so it's worth trying out a few before settling on which works the best for you. They're all free, so you've got nothing to lose.

Plus, by using these free calculator apps, you'll see the benefit of replacing the stock Android apps. You don't need to use what your phone manufacturer has lumped upon you.