At first glance the charts can be confusing. A x/y chart.

If you look to the graphic at the side of of this blog you will see the two axis of the graph x and y.

In a currency comparison graph the x axis is time and can be expressed in minutes, hours, days, months or years. y is expressed in the number of units of currency which can be bought with 1 unit of your base currency.

We will use the graphic below as an example.

This chart is named AUD/USD (Australian dollar/ United States dollar) and has a period of one week

The position of the currencies in the names tells you which is the base currency, in this case the base currency is AUD

Reading from any random part of the graph will tell you how many USD can be purchased for 1 AUD.

For example, if you want to know what the value of the AUD compared to the USD on the 8th of Jan, you would simply look at the part of the line which crosses the 8th of January. We can see that at that date one AUD would buy approximately 1.02250 USD

If you wanted to know what the current rate is you would look at the far right side of the graph. Here we can see that for every 1 AUD aproximatly1.03500 USD can be bought.

I have taken this graph from xe.com. On the website you can drag your cursor across the line to get an accurate value at any given time.