Google apps script custom function that returns latitude and longitude values for given address using the Google Maps Geocoder.

Latitude and longitude values for given address.txt

function GEOCODE_GOOGLE(address) {
  if (address!=""){
    if (address.map) {
      return address.map(GEOCODE_GOOGLE)
    }
    else {
        var r = Maps.newGeocoder().geocode(address)
        for (var i = 0; i < r.results.length; i++) {
            var res = r.results[i]
            return res.geometry.location.lat + ", " + res.geometry.location.lng
        }
    }
  }
}