What size UPS do you need?

UPSs are given a power rating in volt-amperes (VA) that range from 300 VA to 5,000 kVA. This rating represents the maximum load that a UPS can support, but it shouldn’t match exactly the power load you have. To allow room for growth, the best practice is to choose a UPS with a VA rating that is 1.2x the total load you need it to support. If your UPS will be supporting motors, variable-speed drives, medical imaging devices or laser printers, add more VA capacity to your requirements to account for the high power inrush that occurs when those devices startup.

Companies that are anticipating rapid growth should use a higher multiplier than 1.2x. Newer server hardware tends to have higher power requirements than older models, so factoring in additional VA will account for adding more and newer equipment.