* Dynamics of the dollar exchange rate without days off against the euro, ruble, etc.. currencies - this is the latest data, constantly in motion and changing every second, around the clock on weekdays. Usually the time is indicated - point of sale in the market. On different sites and from different sources, the course differs slightly. Difference between buying and selling (bid и ask) on the currency exchange is very small (usd / eur - less 0,001 $), therefore, often only the average value between buy and sell or the rate of the last transaction is indicated. Suitable for "private traders", merchants, and it is this course that is more often laid down in currency converters. Most likely this is the dollar rate you are interested in..
** Dynamics of exchange rates against the Central Bank ruble – official exchange rate of the dollar and euro to the ruble. Issuance of the Central Bank used for special purposes mainly by financial state institutions (state reporting, accounting and bookkeeping) and etc. It is more often indicated in informers on websites, but it rather reflects the course of yesterday. Hence the concept - "Dynamics of the dollar for tomorrow". Use the Central Bank exchange rate if you know exactly what it is.
*** Dynamics of the euro rate on the currency exchange against the dollar, ruble, etc.. currencies - these are the freshest courses, constantly changing many times a minute as a result of trading on weekdays. Usually the time of the course is indicated. Guide for exchange offices, for private transactions with currency, merchants. This course is also laid down in currency calculators. Most often this euro rate - what you need. Difference between buying and selling (bid и ask) on the currency exchange is very small (usd / eur - less 0,001 $), therefore, often only the average value between buy and sell or the rate of the last transaction is indicated.
See also descriptions of dollar rates here:
**** Forecast for exchange rates - analysts assumptions about the dynamics of the dollar, euro, etc.. currencies. Forecasts, news, studying the dynamics of exchange rates on charts allow you to make good money on the currency exchange, despite the fact that it is associated with risk. Trade currencies via the Internet with brokers, forex dealing centers. To do this, it is enough to have an amount in 100 - 1000 dollars.