Generator and UPS calculation: power selection in 5 minutes (Excel)

Generator and UPS calculation: power selection in 5 minutes (Excel)

Which generator should you buy? Which UPS should you install? Calculate it in 5 minutes.

Are you an electrician or a DIY enthusiast? You know that to select a generator, you must account for operating power, starting currents, and power factor (cos φ). For a UPS, you also need to consider the load type. Manual calculations are time-consuming and prone to errors, and such mistakes can be costly: an undersized generator will ´stall´ when starting a pump, and an undersized UPS will fail to protect your equipment.

This calculator solves that problem. Simply enter your list of devices, and receive an instant answer: which generator and which UPS you need.

What it calculates:

For the generator: active power, apparent power (VA), peak power (including starting currents), and recommended nominal rating (kVA) with a 30% safety margin.

For the UPS: required power (VA), recommended power with a 20% safety margin, and UPS type (standby, line-interactive, online).

Reference data: average device power ratings and cos φ values for different types of loads.

Why it’s convenient:

Accounts for starting currents—often overlooked.

Selects the appropriate UPS type—no need to guess.

Secure: formulas are hidden, so users won’t accidentally break the calculations.

Includes examples in the table for easy understanding of how to use it.

Who is it for:

Electricians—to help select equipment for clients.

DIY enthusiasts—for personal use.

Homeowners building or renovating their homes.

Important note: Power ratings are averages. Always verify actual values in the device manual. Starting coefficients apply to devices with motors.

File format: Archive (Excel + Word). Compatible with Microsoft Excel and Google Sheets.