If you want to convert one currency value to another, you can use a formula that automatically updates all the results if the conversion rate changes.
Follow these steps to do it.
1) Open your Excel file with 3 columns «Value in dollar», «Exchange rate» and «Value in euro».
2) Then open Google.com and search «dollar to euro». Find out the current exchange rate between dollar and euro, then copy and paste it in a blank cell (B2).
3) Write the formula =A2*$B$2 in the cell C2 and press Enter.
4) Drag the fill handle over the range cell that you want to contain the formula.