Whether you’re buying a pair of shoes with foreign sizing or trying to work out the difference between an imperial and metric ton, unit conversion tools can be a huge help. No need to tax your gray matter with complicated arithmetic---just type in a quantity, select the units you’re interested in, and the app spits out an answer.

These six unit conversion apps for Android make it a breeze to calculate everything from height and weight to frequency wavelengths and radioactive decay.

1. Unit Converter Pro

Despite its name, Unit Converter Pro isn’t the premium version of a free app. In fact, it’s a completely free app without ads or in-app purchases.

Unit Converter Pro enables you to convert various different units, including depth, currency, data, and so on. By default, it displays the most common units, but if you tap the Show More button at the top, it will also show more specialist ones, such as capacitance, frequency wavelength, and HVAC efficiency.

The units are all ordered alphabetically, so it’s relatively simple to find what you’re looking for. That can mean quite a lot of scrolling, though, so you may want to use the search function. Note, however, it doesn’t accept European spellings such as "centimetre". You can also edit the units in this list, to change their order or toggle their visibility.

If you can’t find the unit you’re looking for, you can add your own custom units in the settings.

Download: Unit Converter Pro (Free)

2. Unit Converter

Sometimes, less is more, and that could well be the case with Unit Converter. Rather than presenting a long list of units for you to pick from, it displays just a few at a time, which you can edit to your liking.

Units are grouped into four broad categories: Basic, Living, Science, and Misc. These are presented as tabs, under which are four unit types. Apart from the Basic tab, you can change what’s displayed under a tab by tapping Favorites at the top. You’re still limited to four unit types, but there’s an extensive list to choose from---not as many as some other apps but enough for everyday use.

Unit Converter isn’t the most advanced unit conversion app, but it’s easy to navigate and good for anyone who converts the same things a lot. We also like that you can remove ads for six hours by watching one video ad.

There is an ad-free premium version too, but it’s worth noting that for just a little more, you can buy Smart Tools from the same developer. This includes the same unit converter, as well as other tools, such as a compass and a sound analyzer.

Download: Unit Converter (Free) | Unit Converter Pro ($2.50)

3. Electricity Converter

Created by the Toastguyz development community, Electricity Converter aims to do one thing and do it well: it’s focused simply on converting electrical units. They range from basics like current and charge to more specialist units like linear current density, electric potential, and electrostatic capacitance.

There are only 15 unit types to choose from, but they’re laid out clearly in a straightforward tile format. Just tap one, and it will take you to a separate screen, where you enter quantities and units.

Electricity Converter also provides brief explanations of what each unit type is. That, combined with the narrow focus of the app, suggests it would be ideal for trainee electricians and students.

Download: Electricity Converter (Free)

4. All-In-One Calculator

All-In-One Calculator is one of the best calculator apps for Android. But it’s a capable unit converter as well.

It doesn’t support as many advanced data types as other unit conversion apps, but it covers all the basics, as well as things like shoe and ring sizes.

You can use All-In-One Calculator to work out a range of math problems too. They include calculating the price of an item after a discount, prime checking, and the volume of 3D objects. You can add favorites to the main screen for quick access.

It’s a good-looking app, with an attractive layout and plenty of color schemes to try.

Download: All-In-One Calculator (Free, premium version available)

5. Engineering Unit Converter

Engineering Unit Converter is another app that focuses on one particular field. That could be ideal if you don’t want to sift through a list of unit types you’re not interested in.

Unit types include the basics, such as length and mass, as well as advanced units like kinematic viscosity and magnetic flux. There are over 20 of them, but they’re not sorted alphabetically. There’s also no search function, so you will need to scroll to find what you want.

The actual unit conversion part of the app is straightforward. Simply type a quantity in the left column, and the conversion appears in the column on the right. Below that are a number of radio buttons representing particular units.

Engineering Unit Converter isn’t feature-rich, and there are very few settings to play with, but it’s clutter-free and straight to the point.

Download: Engineering Unit Converter (Free)

6. Unit Converter

Unit Converter from Digit Grove is one of the better-looking unit conversion apps for Android. It uses a variety of eye-catching icons to represent different unit types, and they’re all laid out neatly and logically.

Units are grouped under various categories: Common, Engineering, Fluids, Electricity, Computer, Light, Time, Magnet, Radiology, and Medical. There are 60 kinds of units in total.

But Unit Converter is more than just a conversion app. It also includes tools for working out common mathematical problems and finance-related matters such as interest rates. Plus it has 34 miscellaneous tools, like a morse code translator, a cryptography encoder, a metronome, and a password generator.

As well as removing ads, the premium version enables you to download conversions to your phone and to create your own custom units.

Download: Unit Converter (Free, premium version available)

Use Google Assistant for Unit Conversion

All Android phones can already do a decent job of converting units. It's just one of the many things you can do with Google Assistant.

You can ask Google Assistant a specific question like "What’s 10 kilograms in pounds?", and it will bring up the answer. Below the answer will be a basic conversion tool, where you can select unit types and enter quantities.

So why bother with a separate app?

If you only want to make the occasional calculation, you probably don't need one. But if you want to convert several quantities at once or if you do it frequently, it soon becomes quicker to use a dedicated app.

They can also be better if you want to see a unit broken down into more than one type of alternative unit. So, for instance, many of the apps will show you a split into yards, feet, and inches all at once.

Unlike Google Assistant, these apps don’t require an internet connection either. If you can’t get online for whatever reason, that’s clearly going to be a major plus point.

Finally, many unit conversion apps support some fairly unusual or esoteric unit types, which Google Assistant doesn’t. That makes them suitable for people who work in specialist fields. And in that capacity, they might work well alongside toolbox apps that enable you to use your phone to take measurements.

Image Credit: Edar/Pixabay