Enter the address for the building you work at and the address of the location you will be traveling to and click Get Directions (and do the same for the return trip). This will give you the number of miles you will use in your GSA mileage rate calculation. Remember to get directions for both the trip out and the trip back, these will each need to be printed and submitted with your Conference Requisition Form. Also, don't forget to add the "to" and "from" number of miles together to get the amount of miles it will be roundtrip, that is the number you will multiply by the current GSA mileage rate.