Navigate to a currency website, such as oanda.com, XE.com or x-rates.com.
Look for the website's exchange rate chart. The website will usually display this on the front page. Find out what 1 yen is worth in U.S. dollars. For example, as of December 18th, 2009, 1 yen was equal to 0.0111 U.S. dollars.
Multiply the amount of yen you have by the exchange rate. This will convert the yen into U.S. dollars. For example, 5000 yen multiplied by 0.0111 equals about 55.50 U.S. dollars.
