Amar Sagoo

10 December 2008


I never used to be particularly interested in designing mobile applications. I just thought it was a hopeless platform, plagued by tiny screens and keys that were designed for inputting numbers (how often do you actually type numbers into your phone?) I also had never thought of my phone as something that I want to use for various applications. This scepticism had become so ingrained that I initially didn't even see much point in Apple opening up the iPhone for third-party developers. I thought it might destroy the purity of this well-designed platform if developers were suddenly given reign over users' mobile screens.

However, two months ago or so, a certain curiosity, a thirst for a new challenge and a feeling that I was missing a boat (to where I did not know) combined to make me go out and buy an iPod touch (I don't want to buy an iPhone because my current phone deal is too good to give up). I almost immediately appreciated both what a well-designed platform it is and what a compelling playground the third-party application market represents, for users and developers alike.

You see, what I had not realised before was that:

  1. My preconception that mobile apps are pointless was based on the fact that previous platforms were so unsuitable for them. I had simply not witnessed how good it can be.
  2. I had forgotten how good Apple are at framework design. The SDK allows you to make rich, highly interactive and very consistent user interfaces rather easily.

I obviously wasn't the first person to think that a unit converter would be an ideal iPhone application. It seemed like the perfect programming exercise, but I didn't want to produce something that was redundant. I had a look at a selection of what seemed like popular unit converters, but none of them worked quite the way I thought they ought to. Like so many times in the past, that was motivation enough for me to sit down and roll my own.

The result is Cambio:

Get it at the App Store. It's free.

I am planning a separate article on the design of Cambio. For now, please give it a spin and let me know what you think. Do you find anything unclear, confusing or annoying about the interaction? Are you missing any units or quantities? Feel free to comment here or drop me an email at


  1. Really really great app. Thank you. Especially for it's free :)

    If you're ever going to translate it to russian I could help.

  2. Thanks for the app. I was using another app - Units. Cambio is cleaner, and stable.

  3. Thanks for your app, very good and well made.
    Any chance to incl the Icelandic krona in the curency converter. Yea I know there I me and that other guy that would like that and no one else but you sure would make two people extra happy beyond alredy thankful souls :)

  4. Looks good, very clean design. Like the concept of showing mutiple values at the same time.

  5. Useful and well crafted app, here. If you want i can make an italian localization (for those lazy italians eesh :). Give me sign, tell me how and i'll ready to start.

  6. If you need a french localisation, I could help.

  7. I have Cambio on my iphone but since I upgraded to OS 3.0 it never worked again. Should it work or not?

    This is the app I use the most, because I'm from Portugal and I am currently in US where all the metrics are different.

    Thanks for this great app.

  8. This is a great app. Very useful and I like the clean interface. However, is it possible for you to add "New Taiwanese Dollar" into the currency exchange? Thank you very much. :)

  9. I just went back through every one of your blog posts. They were all very informational and enjoyable. Thank you.

  10. Hopeless app

    Very basic and difficult to see why it is needed

    Zero rating

  11. I use both Cambio and Tofu and just visited this site in the wake of the iPad announcement to see if any porting might happen.

    I was disappointed to see a negative comment in this list, so I would like to mention that I often cite Cambio and Tofu as examples of the development Apple must attract to stay healthy. I have an equivalent Nexus One (Android) app to Cambio and it just does not compare in terms of thoughtful design. In the case of Tofu, there is of course, no comparable tool.

  12. What happened to Cambio? I can no longer find it on the app store. It was perfect for converting money while traveling!