It depends on the size of the UPS. In every datasheet the maxium capacity is given in watt and VA. Most devices like PC’s, printers, etc, show watt usage/consumption. When selecting appropriate UPS for your load, you need to consider not only nominal power consumption but also maximum power consumption, peaks, in-rush currents and even harmonic distortions. On top of that a safety margin is advised. We suggest not to connect more than 75% of the nominal watt power capacity of the UPS.