I’m lucky enough to have lived in several overseas countries, and when living in the US I travel overseas a lot. Given that we in the US are the last holdouts to use the archaic “English” measurement “system” that not even the English use anymore, I often have the need to convert metric units into English, or the other way ‘round, and to convert foreign currency to and from $US. Whether it’s cooking, buying gasoline, trying to figure out whether 20C needs a sweater, or whether 10,000 Rwandan Francs is a lot for a bottle of wine, I keep a unit conversion app on my home screen. Fortunately, unit converters are as common as to-do apps or notepad apps, and I’ve tried many over the years. For me, Measures HD for iPad hits the sweet spot of having all the features I need, with none that I don’t to clutter up the app, all presented in a simple, intuitive user interface.
While Measures also has a companion iPhone app, it really shines on the iPad, using all that extra screen real estate to good advantage. Measures is a one-screen app so everything you need is immediately visible. You start by using the three scrolling lists on the bottom of the screen. First pick the kind of unit you want to convert: length, volume, temperature, etc. Then pick the “from” units, then the “to” units. Enter the from amount (100ml in the example above) in the calculator interface and voila, the to unit appears. For example, to see how long my morning stationery-bike ride was, so I could enter it in miles in Apple’s Health app, I picked “length,” then “km,” then “mi” and entered 19. The mileage (12) appeared instantly. There is every kind of unit you can imagine, and many I’ve never heard of.
At the top, middle of the screen is a cross-arrows button that lets you immediately reverse the direction of conversion. In my example this button would have changed the conversion from miles to kilometers. This is especially useful for converting currencies to and from USD. Next to the reverse button is a Wikipedia button which may be useful for looking up the more arcane measures (what the heck is an “Angstrom?”).
For me one of the features that sets Measures HD apart is the “favorites” board on the left. You can create favorites for conversions you do a lot so you don’t have to scroll the three wheels on the bottom. In everyday use this saves lots of time. As you can see from my screenshot, I convert RWF to and from USD several times per day (Measures HD updates the currency exchange rates at open). So being able to tap a favorite is a real convenience. You can have any number of favorites and creating one couldn’t be simpler: scroll the three lists to get the conversion you’re looking for and tap the + button above the favorites list, and you’re done.
There are converters that are prettier, at the expense of usability, and converters more jam-packed with features, at the expense of simplicity. But Measures HD is the quickest, most intuitive, and most convenient that I’ve tried. I you have another recommendation, let us know in the comments. Measures HD is rated five stars and is a steal at only $1.99 in the iTunes store.