In 2018, the exchange rate between the US dollar and the euro varied throughout the year. The value of $1 to the euro began the year around 0.83 euros and reached its peak at approximately 0.88 euros in early summer. However, as the year progressed, the exchange rate fluctuated and by the end of 2018, $1 was worth around 0.88 euros again. It is important to note that exchange rates can be subject to continuous change due to various economic factors.