How to Convert Anything on Your iPhone

How many yards are in a mile? How many ounces are in a cup? What’s the current conversion rate of dollars to euros? The apps in this post are built specifically to answer these questions.

Today we’ll take a look at three solutions for converting almost everything you can think of on your iPhone. We’ll start with two of the best paid options out there and conclude with a free but adequate alternative.


ConvertBot is one of the nicest looking converters available on the iPhone. The beautiful gray and blue interface and smooth animations really make the dull task of converting units a pleasure to undertake.

Price: $1.99
Developer: Tapbots

Interface and Usage

Convertbot implements a unique circular interface for converting units. To convert something, you spin the wheel around or simply tap on the type of unit you want (weight, speed, etc.). The icons are fairly straightforward and make it easy to quickly grab your desired option.

After selecting the type of unit the circular grid opens up and reveals the options within that unit. For instance, under “length” the wheel is divided into cm, mm, in, etc.


Convertbot's Circular Interface

After you select your units, tap on the rectangular area at the top of the screen to input the specific numbers that you’d like to see converted. By default, this will open up a simple number pad but in the settings you can enable a calculator in this view that will allow you to make calculations in addition to simply typing in numbers.


Using the Calculator to Input Unit Amounts

Convertbot makes it easy to swap the “from” and “to” variables at any point of the conversion by hitting the button with arrows going in opposite directions.

The circular system admittedly takes a little while to get used to but after spending a few minutes with the app you’ll be able to convert and switch units fairly quickly.

Units Available

Convertbot has a huge selection of units to choose from (over 500). By default, most of them are turned off and can be activated in the Settings screen. Below is a list of categories available. For a complete list of units, visit

Category List:
Angle, Area, Currency (requires Internet connection), Data Rate, Data Size, Force, Fuel, Illuminance, Length, Mass, Power, Pressure, Radioactivity, SI, Speed, Temperature, Time, Typography, Volume, and Work

Convert ~ the unit calculator

Convert is another multi-unit calculator with a very attractive interface. It’s currently on sale so if you’re at all interested, buy sooner rather than later so you don’t miss out on the price drop.

Price: $0.99
Developer: Tap Tap Tap

Interface and Usage

The Convert interface is super streamlined and extremely intuitive. Though not quite as pretty as Convertbot, it’s a lot easier to pick up and use with no instruction.


Convert's Three Column Interface

As you can see, Convert features three columns and a calculator/number entry pad. Simply slide your finger vertically along a column to select a unit category and the two specific units you’d like to convert between. The pertinent information is displayed across the center of the columns and highlighted to make it easy to spot.

By eliminating the need for submenus, this system makes switching categories and finding the information you need a noticeably faster process than on many competing apps.


More Features

Units Available

Like Convertbot, Convert has a fairly large list of available units that will undoubtedly cover most of the things you can dream up to convert. Also similar to Convertbot is the ability to make calculations while typing in the numbers to convert using the built-in calculator.

Category List:
Angle, Area, Computer, Currency, Energy, Force, Length, Power, Pressure, Speed, Temperature, Time, Typography, Volume and Weight

Convert Everything

Now that we’ve discussed two of the nicest conversion apps out there, lets finish by looking at a free alternative. Convert Everything “Free” is a surprisingly fully featured, ad-supported app that will convert much of the same units as the pricier apps, and even some things they don’t cover.

Price: Free
Developer: Cristian Bica

Interface and Usage

The interface isn’t as nice as either of the paid apps above, but it gets the job done. Tap the buttons at the bottom of the screen to change the conversion type and use the arrows at the top of the screen to scroll through subcategories.


Convert Everything FREE

In addition to standard units and currency, Convert Everything Free contains a useful language converter that uses Google Translate to help you translate words and phrases into a variety of languages.


Translate Words and Phrases Using Google Translate

Overall, I thought the app was great considering the price. It’s much better than most of the free “lite” versions of paid apps out there (though there is an ad-free paid version of this app). My biggest complaint was that tapping the little arrows to find the category you want seems like a major inefficiency and should be replaced with something quicker and more direct.

Units Available

As stated above, this app contains many of the units found in the other apps above and even enhances the offering with the addition of a translation tool.

Category List:
Area, Distance, Energy, Information Storage, Power, Pressure, Speed, Temperature, Time, Volume, and Weight


The three apps above represent some of the best options available for converting units on your iPhone. Convertbot and Convert feature amazing interfaces, smooth animations, and tons of units. However, you have to ask yourself whether you convert tablespoons to ounces so often that you can justify dropping a few bucks to do so. If not, then you’ll definitely want to download Convert Everything Free, a worthy and free competitor to the paid apps.

Use the comments below to let us know which app you’ll be downloading. I’m interested to hear whether you think converting units in style is a service that’s worth paying for in light of perfectly capable, though less attractive, free alternatives. As for me, I was fortunate enough to score Convertbot back when it was free so I enjoy the best of both worlds.