Common Method For Ups Requirements And Max PoE Switches

We have a scheduled office move where we are consolidating 2 remote offices into one. I’ve been asked to spec out the correct size UPS to support all of the network equipment for this new office.I went to the Cisco website and I see on the datasheet for the switches and router where they talk about the wattages and BTU’s but how can I go about deciphering from that information what my total wattage and BTU will be for each switch and router?What numbers should I be looking at? For instance, we have 3 3750 48 port PoE switches. So if I look at the datasheet for that switch they have 4 different columns, one for 100% throughput power consumption, one for 5% throughput, another one for 100% throughput for max PoE load and one for 5% throughput with 50% PoE loads?Is there a common method for deremining UPS requipments? For the switches I pretty sure I need to assume max PoE load in the event every port has a phone plugged into each port.