1. The importance of the Interbank Rate
What you would like to see online is the interbank rate so you could truly ascertain whether your rate was good or not.
The interbank rate is the rate at which banks buy and sell currency to each other (lets call this trade price) and this is not freely available to members of the public. In fact organisations such as ourselves have to pay a subscription in order to be able to access interbank currency rates.
Importantly, you should also be aware that exchange rates float freely against one another, which means they are in constant fluctuation. They do not change once per hour or even once per second but constantly.
Therefore, the currency rate you see online is more than likely a rate which already has a margin applied to it or is out of date.