The Android Market is abound with Unit Converters, a simple search for these keywords yields hundreds if not thousands of results. Some of these are great, others lack important features, and others are ridiculously highly priced for a regular feature set.
What if you wanted a simple converter with a nice interface, or one with every possible unit you could think of from Ancient Rome to modern International System (SI) units, or one that went beyond the regular converter function to offer an additional value? Here, we take a look at some of the best, and free, unit converters available for your Android handset.
Ultimate Converter is one of the simplest yet most elegant unit converters on the Market. It supports 250 different units in a total of 18 categories (17 currently, as the Currency conversion is disabled).
Its strength lies in its dark grey theme with visible and well differentiated categories and icons, as well as the presence of a button to easily swap the “to” and “from” fields. On the downside, it doesn’t support negative values for conversion so there is no way to know what -10℃ is in Fahrenheit.
Convert Units Free is another free and yet gorgeous looking application. With only nine categories and a few units for each, it’s not as extensive as many of the other applications on this list, but it makes up for it with its clean white and blue interface, and its spinning wheels system for changing categories and units.
The app also supports decimals, negative values, and easy “to”/”from” units swapping. The only regrettable aspects are that the units spinner is too narrow making it difficult at times to get to the unit you want, and that it won’t work on devices with smaller screens like the Galaxy 5 and the HTC Wildfire.
Like the name suggests, Simple Converter is as simple as they can get. There are only six categories for conversion, with a few units each. However, these categories are easily accessible with one click of a button throughout the whole application, and they are the most used ones: area, length, volume, temperature, weight and numbers. The units can be swiped left or right to reveal more options for each category. Simple Converter supports decimals, but doesn’t support negative conversions.
With support for 11 categories, UnitConverter offers a bit more than other simpler applications on this list. The application’s interface is all taken by the category spinner, the “to” and “from” fields, and the number pad. Clicking on the units on the left reveals a regular Android selection window with all available units for each category.
Good looks aside, UnitConverter regrettably lacks support for negatives and easy swapping between to/from units fields.
Although limited to four categories, Convertor Lite is one of the most thought-through applications in the Market. It supports landscape mode, decimals, negatives, copy and paste, and doesn’t stop there since it includes a calculator to do basic mathematical functions before converting and will even offer mixed units. For example, it’s possible to convert days to minutes + seconds, or kilograms to pounds + ounces, or centimeters to feet + inches… you get the idea.
If that’s not enough, Convertor Lite also comes with a clean interface and a nifty slide to transition between different categories or units. If these animations don’t impress you, you can always long-press on the selection areas to get a list of the different options. A paid version exists (Converter Pro), removing the category limitation and implementing 400 units in 25 categories.
Convert This! does away with the fancy graphics and looks to focus on an easy to use application. A total of 13 categories are available; tap one and you’re presented with a list of all the units that are supported. You can type a value inside any of these text boxes and will instantly be given the conversion value for all other units. Convert This! supports landscape orientation, negative and decimal values, and works really fast.
With over 50 categories and multiple units in each, Unit Converter is one of the most extensive applications on the Market. Its main attraction is the addition of less known categories like typography, conductance, entropy, luminance, and its support for negative values, decimals, and landscape orientation. Like Convert This!, you will only need to enter a value once in the top field in order to get all the different conversions with one click.
ConvertDroid is quite similar to Unit Converter in many of its features. However, it uses a different UI, with a double column of categories, and adds some nice functions in the ability to do mixed units conversions.
It will be possible to use it to convert time to a YY:MM:DD-hh:mm:ss format for example, or distance to a ft:in format. Multiple conversions are possible instantly and ConvertDroid supports about 58 categories of units, with a full section for clothing sizes, including shoes, shirts, hats, rings and others.
ConvertMe(Beta) definitely isn’t one of the most beautiful converters out there, but it makes up for it with probably the best feature set amongst the competition. 65 categories and 1500 units are included, which make up for quite nice surprises: did you know that length used to be measured in Stadium Ptolemey in Ancient Greece, or that there is a Russian weight unit called Dolya? Thankfully, there’s a search function allowing you to easily find the unit you’re looking for, instead of scrolling through dozens of ancient ones.
The app works in landscape mode, and supports negatives and decimals, and easy to/from field swapping. Unfortunately, it doesn’t have the Clothing conversion of ConvertDroid, but it does include a tip calculator.
EZKonvert comes with the most simple to use interface: choose a category, type the number to convert, pick a conversion “factor” and click Convert to get an answer. You don’t get to separately pick the “from” and “to” units, but you pick one of the 450 factors available, and these take into consideration the full conversion — for example, both “Celcius to Fahrenheit” and “Fahrenheit to Celcius” exist.
The ease of use of EZKonvert is however hampered by one aspect: the resulting conversion value appears in the same box as the original input value, making it difficult to tell whether you input your numbers correctly or made a mistake. It also doesn’t support negative values.
More Than Converters
Don’t let the calculator-like interface of Units fool you; this is a full-fledged converter. Yes, it will do basic calculations, but it also supports conversions in over 2400 units. It will take you a while to get used to typing a regular number value, then hitting Units to define the “from” and “to” fields, but it gets easier as you do it continuously. Units also supports landscape orientation, negatives and decimals, and will show you the conversion result clearly at the top of the screen.
ConvertPad is, feature-wise, quite similar to Unit Converter, with multiple simultaneous conversions and support for thousands of units in 89 categories, negatives, decimals and landscape orientation. However, it adds the ability set some of these as Favorites so you can tidy and simplify the interface if you wish. You can also add your own conversion units and rate factors, giving ConvertPad a highly personalized approach to converters.
handyCalc hits this list as a fully featured mathematical tool: it includes a scientific calculator, a graph plotter, a currency converter and a units converter.
For the free price tag, handyCalc does really well in covering all four aspects, with the units conversion function including thousands of units, a “stick-it” option to send a particular conversion to your Android homescreen, and the ability to hide some less well-known units. Also supported are negatives and decimals.
RealCalc is basically a scientific calculator, but under a Shift-0 function resides a 12-category converter. The interface might not be well-suited for those looking mainly to do conversions, but it will be more than enough if you want a decent calculator with scientific functions and a converter all built into one.
Convert Units takes a different approach to conversion than all previously mentioned converters. It is an online Google-reliant utility that uses the Google API to handle text-based conversions.
Simply type “959 km in yd” and it will understand the initial value and unit and the desired conversion outcome. The same can be applied for all other units and categories that Google Search can handle, including volume, length, temperature, area and more.
Picking The Best
After having tried many of these converters, I have some obvious favorites in each category. handyCalc Calculator stands out as the best all-round choice, with a calculator, converter and graph plotter all included. As a standalone converter, ConvertDroid offers the best feature set with a decent looking interface and all the units you can want. As for beautiful converters, Convert Units Free has all the basics covered once you get used to the limited unit selection screen estate, but if you’re willing to pay, Convertor Pro for $1.50 is just one of most featured and smooth operating converters out there.