As someone who was born overseas, I pay perhaps an atypical level of attention to the currency market, trying to track the relative worth of goods as things fluctuate. And fluctuate they do, the currency market is extraordinarily volatile and it's awful easy to lose a lot of money on a transaction like an overseas hotel reservation if you're not paying close attention. And those Euros and Pounds, Yen and Lira that you've kept as souvenirs? Yeah, as the market fluctuates those can end up devaluing even as they just sit innocently in your scrapbook.

There are a ton of different ways to convert currencies too, and I'd never even thought about using an Apple iPhone app. A quick search reveals over 150 applications in this space. What the deuce?! Is there that much variation in this fairly straightforward calculation??

Anyway, I'll highlight three ways you can quickly and easily convert from one currency to another, using as my example the calculation of the USD equivalent of 100 British Pounds Sterling.

The first way, the one I prefer, is to use Google. Yup, a quick Google search in the correct format and it'll figure out the results right there in the search engine:

Notice the query I entered: convert 100 gbp to usd. The result not only shows you that it's worth $164.57 with the current exchange rate, but even has a graph that shows how in late 2007 it would have been worth a lot more, but early 2009 would have made it worth even less. If you have thousands or tens of thousands, small market fluctuations can have big impact, needless to say.

While we're here, click on "View more conversions" to see what Google can do:

Yup, once you've made a conversion, it's really easy to bounce around other currencies if you want to, for example, find out how much that same 100 GBP is worth in Kuwaiti Dinar, Euro, Bulgarian Lev, Indian Rupee or Paraguayan Guarani. In fact, Google tracks over 75 different currencies including all the common ones (US Dollar, Canadian Dollar, Mexican Peso, Japanese Yen, British Pound Sterling, Euro, Chinese Yuan) and some sufficiently obscure that one imagines it's a very rare day in the Googleplex that the conversion utility taps into the value of the Fijian Dollar, Cayman Islands Dollar or Namibian Dollar.

Currency Conversion on a Macintosh System

If you're using a Mac OS X system, there's another way you can convert currencies and I'm sure that less than 1% of Mac users are aware of it: Calculator. Yup, that humble little four-function calculator turns out to have a lot of interesting additional capabilities.

All you need to do is enter the amount in the calculator app, then select "Currency..." from the "Convert" menu:

Notice all the other things Calculator can work with, from units of energy to power, pressure, speed and even weights and masses. Spend a few minutes, check out the Calculator "convert" help.You'll thank me one day!

Once you choose "Currency..." it'll prompt you to enter the starting and target currency (pop-ups that have considerably fewer options than the Google utility, by the way) along with a note about the last time the currency exchange rates table was updated. If it's in red, it's out of date, so click on "Update" and give the utility about ten seconds to update things.

When you're ready and you've specified both the input and target currencies, click on "Convert" to get the answer:

Nowhere near as elegant (and it ain't common to find that an Apple utility is so dramatically less elegant than a simple Web app!) but it does the job in a pinch. There are some nice Dashboard alternatives for currency conversion too if you want to explore them. Start with the slick Currency Converter if you're a Dashboard aficionado.

Currency Conversion on a Windows PC System

If you're running a Windows PC, I'll show you something really cool that Microsoft includes in Windows 7 (and, as far as I know, earlier versions of Windows too), a currency conversion gadget that can sit on your desktop ready to go whenever you need it!

To start, enter "currency" into the search box on the START menu:

Notice the fourth entry, "Add gadgets to the desktop". Since it matched our search for "currency", that's a good sign, right? Click on it and you'll see the slick gadgets that Microsoft includes with Windows 7:

Do not get lost in the picture puzzle gadget. Just don't do it. Life is too short. :-)

Currency is the one we want - as I have highlighted - so click on it and it'll appear on the Windows desktop and load up the current exchange rates:

I like that it looks like some sort of "gold card" credit card. Makes me feel very cosmopolitan when I install it! Once it's gotten the exchange rate data, it's ready to go:

Before you go further, put the cursor over the gadget and the tiny menu pops up on the right. Click on "X" to delete it if you want, but for now, click on the arrow in the box. That'll make the gadget itself just a bit larger and easier to work with.

Now, click on the downward triangles to set the currencies you want to work with. Here I want to convert from USD to EUR, and you can see that without entering a value, I can already see that $1.00USD = 0.692EURO.

Wondering what currencies are supported? A good set, maybe 40-50 or so. More than the Mac app, but less than the Google converter utility:

Finally, here's our conversion again, 100 GBP to USD:

Between these three paths, lots of options for calculating currency exchange rates without pulling your iPhone out of your pocket. Hope it's helpful!