This PUE calculator works out a data centre’s or server room’s Power Usage Effectiveness: how much of the energy you pay for actually reaches the IT equipment, and what the rest costs each year. It runs entirely in your browser: nothing you type is sent to our server.
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Table of Contents
What PUE means
PUE = total facility energy ÷ IT equipment energy. A PUE of 1.0 would mean every kilowatt goes to servers, storage and network gear; 2.0 means you use as much again for cooling, UPS losses, power distribution and lighting. DCiE is the inverse, as a percentage.
| PUE | DCiE | Typical of |
|---|---|---|
| 1.1-1.2 | 83-91% | Large modern sites with free cooling |
| 1.3-1.5 | 67-77% | Well-run colocation and enterprise data centres |
| 1.6-2.0 | 50-63% | Older data centres |
| Over 2.0 | Under 50% | Small server rooms with comfort air conditioning |
Measuring it properly
- Measure total power at the utility meter and IT power at the UPS output or the PDUs.
- Use a full year of energy (kWh), not one instant reading: cooling load changes with the seasons. ISO/IEC 30134-2 defines the method.
- Server rooms gain most from blanking panels, hot/cold aisle separation and raising the cold-aisle temperature within the ASHRAE recommended range.
How we checked it
We checked the outputs on 11-12 October 2026: 1,500 kW total and 1,000 kW IT gives PUE 1.50, DCiE 66.7%, 4,380 MWh of overhead a year and 657,000 at 0.15 per kWh.
Frequently asked questions
What is a good PUE?
Below 1.5 is good for an enterprise data centre; large hyperscale sites run around 1.1-1.2. A small server room cooled by office air conditioning is often above 2.0.
How do I calculate PUE?
Divide the total power drawn by the facility by the power drawn by the IT equipment. 1,500 kW total and 1,000 kW IT gives a PUE of 1.5.
Can PUE be less than 1?
No. The IT load is part of the total, so PUE is always 1.0 or more. A lower value means a measurement error.