A UPS Power Supply Calculator is an online tool that helps determine the required UPS capacity in Volt-Amperes (VA) based on the power consumption of your devices and the backup duration you require. Estimate recommended UPS wattage, VA capacity, runtime energy, and battery pack count for routers, servers, PCs, switches, and security gear before the next outage. Follow these steps to get accurate results: 1. Enter Total Wattage (W): This is the combined wattage of all devices that will be connected to. In today's world, uninterrupted power supply is critical for both home and business environments. But how do you know which UPS is. Due to the potential complexity of these configurations, we recommend working with an Eaton Power Specialist to determine the best combination of products.