This calculator will tell you the recharge efficiency for your Access Level and distance to the portal you wish to recharge. The calculator uses this equation to power its results: Efficiency (%) = 100 - (distance from portal in km)/(5 * Player Level)
To use the calculator, select your player's access level and the distance between you and the portal you wish to recharge in kilometers. Then click the calculate button.
The results below will give you an indication of the effectiveness of your recharge. Meaning the lower recharge efficiency will yield less of a charge at the same cost. You use XM to recharge resonators on a portal. Lets say you use 100XM to recharge a portal. If you are at 100% recharge efficiency, then you are getting more bang for your XM buck versus being at 60% efficiency. Please keep in mind, that below 50% efficiency, it is not possible to complete the recharge action and you will receive a response stating you are out of range.