Google Maps will calculate driving, walking, cycling, public transit or flying distance between two locations on a map. Free Map Tools will calculate the geodesic distance ("as the crow flies") between two locations.
From the Google homepage, the Maps feature is located by clicking the grid in the top right corner and then clicking the Maps icon. Entering any location by state, city or full address will display it on the map, and selecting the Directions icon will allow entering a second location to calculate the distance. The icons at the top of the Directions box allow selection of driving, walking, cycling, public transit or flying distance.
From FreeMapTools.com, selecting "How far is it Between" will display the distance tool. Entering two locations by state, city or full address and clicking "Show" will calculate the geodesic distance between the two locations and display the route on a map.