To calculate the distance in miles between two points in Excel, you can use the the Haversine formula.

=ACOS(COS(RADIANS(90-Lat1)) *COS(RADIANS(90-Lat2)) +SIN(RADIANS(90-Lat1)) *SIN(RADIANS(90-Lat2)) *COS(RADIANS(Long1-Long2))) * 3958.756

This was inspired by BlueMM: Excel formula to calculate distance between 2 latitude, longitude (lat/lon) points (GPS positions) .