THe software does what it promises, calculating distances between zips and zips within a given radius. However, if you have any difficulties--such as with wanting to reset your license after rebuilding your desktop, etc--don't expect much customer support as Spheresoft is unresponsive. Also, the functions are slow to calculate if you use them in many cells at once, so once you've done the calculation, you may want to replace the cells' formulas with exact values. ("alt","e","s","v", "enter")