Enter your latitude and longitude. If you know your latitude and longitude in decimal degrees (e.g., 41.714), enter those values into the "degrees" fields and leave the "minutes" and "seconds" fields blank. If you know your latitude and longitude in degrees, minutes and seconds, enter the values into the appropriate fields. (Don't enter both decimal degrees and minutes/seconds!) Be sure the correct directional buttons are selected.
Note that only the integer degrees (not the fractional part or the minutes and seconds) are needed to calculate the 4-digit grid square, but providing the exact values will allow the program to calculate the distance from the specified location to the nearest edges of the grid square. This is useful for determining how accurately you must know the location to be sure of the correct grid square. Finding the 6-digit grid square requires degrees and minutes.