Power Usage Effectiveness
Calculate PUE, the ratio of total facility power to IT equipment power, for a data center.
About Power Usage Effectiveness
PUE is the ratio of total facility power to the power actually delivered to IT equipment. A PUE of 1.0 is the theoretical ideal — every watt goes to computing, none to overhead — but is not achievable in practice, since cooling, power distribution losses, and lighting always consume some energy. Most modern facilities fall in the 1.4-1.6 range; hyperscale operators with advanced cooling (free-air, liquid) push below 1.2, while older or poorly optimized facilities can exceed 2.0.
Formulas
Power Usage Effectiveness
PUE = total_facility_power / IT_power
Data Center Infrastructure Efficiency
DCiE% = (1 / PUE) × 100
Worked example
With the default values below, Power Usage Effectiveness returns PUE of 1.500. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total Facility Powerminimum 0.01 kW
- 150 kW
- IT Equipment Powerminimum 0.01 kW
- 100 kW
Results
- PUE
- 1.500
- Efficiency Rating
- Typical — industry average range
- Data Center Infrastructure Efficiency (DCiE)
- 66.7%
- Non-IT Overhead Power
- 50.0 kW
Step by step
- 1Values used
- 2Power Usage Effectiveness
- 3Data Center Infrastructure Efficiency
- 4PUE= 1.500
- 5Efficiency Rating= Typical — industry average range
- 6Data Center Infrastructure Efficiency (DCiE)= 66.7
- 7Non-IT Overhead Power= 50.0 kW
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What is a good PUE value?
1.0 is the theoretical ideal (all power goes to IT, zero overhead) but is unachievable in practice. Values of 1.2-1.4 are considered excellent for modern facilities, 1.4-1.6 is typical/average, and anything above 2.0 signals substantial non-IT overhead worth investigating.
What drives PUE above 1.0?
Cooling systems (chillers, CRAC/CRAH units, fans), power distribution losses (transformers, UPS conversion inefficiency, PDU losses), and facility lighting/support systems all consume power without contributing to computing — the sum of these is the 'overhead' that pushes PUE above the ideal 1.0.
How is DCiE related to PUE?
DCiE is simply the inverse of PUE expressed as a percentage — it answers 'what fraction of total facility power reaches IT equipment?' A PUE of 1.5 corresponds to a DCiE of about 66.7%, meaning roughly two-thirds of facility power is used productively.