Today, 1.00 (one) Euro is worth 1.09 Dollar, ie, €1.00 = $1.09. That's because the current exchange rate, used to convert to Dollar, is 1.09. So, to make Euro to Dollar conversion, you just need to multiply the amount in EUR by 1.09, the currency rate today.
Euro (EUR) to US Dollar (USD) Cheat Sheet Table
You can print out and cut this "currency table" also known as currency 'cheat sheet' for travellers or 'pocket guide' and keep it with you. During your travel you can compare currency amounts in foreign currency with your own home currency and vice-versa, so you will not need any calculator or mobile app get an idea of how much you will pay for a product or service.
Print out this Euro to US Dollar Currency Table