Money Math Tricks

Ever wander into a country and realize that you have no idea what the conversion rate is?

Usually before I travel, I research what the conversion rate is from my US dollar to what the currency is in the country I plan on visiting.  But sometimes, life takes you on a journey that you did not anticipate and then you’re standing in the airport not knowing if you’re getting ripped off, not knowing how much to take out of the ATM, and not knowing how much a hotel or taxi should cost.  And you need to figure this out on the spot in order just to get out of the airport terminal!

Don’t stress.  This advice is more about common sense than it is about math…  Ok, some of you a still stressing even with that being said… Nevertheless, there are a few things you can do to figure out the money situation:

Option 1: Ask at the Currency Exchange Booth.

Airports always have a currency exchange booth – by the baggage claim, by the exit, and sometimes an airport will have more than one in a few different places…  You really can’t miss these…

Even though these currency exchange booths are only for exchanging cash for cash [and this is not necessarily what you want], you can still ask the person working what the current exchange rate is.  For example, ask how much US$100 will buy in the local currency.  Use easy numbers to work with… I personally think 100 is the easiest [read more about this below].

Option 2
Use the Internet

If you have the internet on your phone, great.  If not, then there are a lot of airports nowadays that have free internet stations.  Ask anyone working in the airport if this exists in the airport you are in and have them point you in the right direction.

Once you have the internet, go to the website in order to convert your native currency to the local currency.  Again, work with easy numbers…

Option 3
the ATM

I’m assuming that you’ll need money out of the ATM in order to get a taxi, bus, hotel, etc.  Since you need the cash out of this machine anyway, you might as well use this conversion for the basis of what the local money.  Here’s what you do:

Go to the ATM and push one of the options on the screen [don’t choose to enter your own amount].  The options on the screen aren’t going to be worth too much money, but if you enter your own amount, you could be entering an amount that is worth more than a new car without even realizing it.  Of course the ATM will not allow you to take out that amount of money, but it will still be annoying to go through the all menu again…

Once you’ve chosen a random amount on the screen and received the local money from the machine, make sure to GET A RECEIPT!  This is going to be what you use to base the money on until you get a better understanding of the money…

If the receipt said you took out US$300 and you see you have a million in local money, then you know that 500,000 in local money is about US$150.

Easy Numbers:

When I was in Bali, the money was the most different from my U.S. dollar than pretty much any other country I’ve been in.  When I arrived, I went straight to the ATM and choose the highest amount of money on the screen [because I know that the options on an ATM screen aren’t going to be more than US$400 or so]… It then spit out 1,500,000 Rupiah and told me it was equivalent to US$170.  OK, so now I know the conversion… and when there’s a currency with a lot of zeros on the end, start taking some zeros off!




Work with Multiples!












What you’re really doing when you’re “taking off zeros” is just moving the decimal over to the left, to make smaller numbers – because the smaller numbers are what you’ll be dealing with on a day-to-day basis. Doubling, tripling, or taking half of both numbers is a good way to know other exact money amounts without moving the decimal.

Use both of these fast and easy tricks in order to at least get you out of the airport and into a place to rest!

So when I arrived in town and found a hotel for 125,000 Rupiah, I knew it was under US$17.  Whether it was US$14, US$12, or US$8, who cares?  At least I have this base to work off of and know that a hotel isn’t costing me US$50 per night.

If you need to use the calculator function on your cell phone or ipad, go for it… but these are the two most simple and most useful tricks I can think of in order to do fast easy math on the spot – this way, when there’s chaos at the airport and taxi drivers yelling at you and a huge line of people, you don’t need to be looking for your cell phone at the bottom of you bag, or worrying about if it’s dead.

Do YOU have any easy tricks in order to convert money on the spot?  Let’s hear how YOU do it!

One comment

  1. A few tricks: do the math ahead of time and carry a small card with the basic numbers done as a reference. Or pay attention to what you usually pay for things. If a cappuccino is always 2 euros and someone wants 6, something is wrong. Try to get a feel for the lifestyle there. If Coke is imported and is $4 a can, see what the locals are drinking. A Fanta (like 7 Up) in Spain was 30 cents when Coke was $2.50. I also found that the ATM was the cheapest way to exchange money in most of Europe. With my Visa card the exchange rate was only 1% compared to 4% at the banks and that plus a commission at the currency exchanges. I like your system of using $100 as a base and then doing multiples. You really explained that well.

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