UPS Sizing Calculator
The UPS Sizing Calculator picks the UPS kVA rating and reports loading for a critical load and backup time. Example: for a 50 kW critical load on an online double-conversion UPS with 15 min backup, Recommended UPS = 100 kVA, Load = 55.56 kVA, Loading = 55.6 % (per IEEE 1184:2006 | IEC 62040-3:2021 | IEEE 446 | BICSI 002).
How it works
Computed from your inputs per IEEE 1184:2006 | IEC 62040-3:2021 | IEEE 446 | BICSI 002.
Worked example (Electrical & Power)
Inputs: a 50 kW critical load on an online double-conversion UPS with 15 min backup.
| Result | Value |
|---|---|
| Recommended UPS | 100 kVA |
| Load | 55.56 kVA |
| Loading | 55.6 % |
Computed live by WorkHive's calculation engine; standard: IEEE 1184:2006 | IEC 62040-3:2021 | IEEE 446 | BICSI 002.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a 50 kW critical load on an online double-conversion UPS with 15 min backup.
- The calculator returns Recommended UPS, Load, Loading, computed per IEEE 1184:2006.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a UPS sizing calculator kVA?
The UPS Sizing Calculator is a free online tool that computes picks the UPS kVA rating and reports loading for a critical load and backup time. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following IEEE 1184:2006. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive UPS Sizing Calculator in WorkHive: free, no sign-up needed for the calculators.