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LoadCairn / Facility efficiency

PUE calculator (and DCiE).

Compare total facility power with IT load to estimate power usage effectiveness, infrastructure efficiency, and non-IT overhead. Change assumptions in your browser.

Want to review the method first? Read the PUE & DCiE calculator guide

Facility inputs

Illustrative example · editable

The starting example is 500 kW facility power and 400 kW IT load. These editable values do not describe a LoadCairn customer site or an industry target.

Enter facility input power for the measurement interval and boundary you are evaluating.

Enter IT equipment power measured over the same interval and boundary.

Unsaved · Calculated in your browser

Live planning estimates

Facility efficiency results

Power usage effectiveness (PUE)
Planning estimate only
1.25ratio
Data center infrastructure efficiency (DCiE)
Planning estimate only
80%
Non-IT overhead
Planning estimate only
100kW
Checking Pro access…Download PUE reportExport CSV

Estimates for planning only, not a substitute for a licensed engineer’s design or manufacturer data.

Calculation details

Current input snapshot

Total facility power
500 kW
IT load
400 kW
Annual estimate
Off

Formulas and live calculation trace

  • PUE = total facility power ÷ IT load
  • DCiE (%) = IT load ÷ total facility power × 100 = 100 ÷ PUE
  • Non-IT overhead (kW) = total facility power − IT load
  • Annual energy (kWh) = total facility power (kW) × 8760 hours/year
  • Annual cost = annual energy × entered electricity price ($ / kWh)

500 kW ÷ 400 kW = 1.25 PUE — planning estimate only

400 kW ÷ 500 kW × 100 = 80% DCiE — planning estimate only

500 kW − 400 kW = 100 kW non-IT overhead — planning estimate only

Calculations use unrounded values; displayed results are rounded for readability.

Assumptions

  • The kW inputs represent power measured over one matching interval and at one matching facility and IT boundary.
  • IT load is greater than zero and does not exceed total facility power; equal values produce PUE 1, DCiE 100%, and zero overhead.
  • The optional annual energy estimate assumes constant total facility load for 8,760 hours, with no leap-year adjustment.
  • The optional annual cost uses the entered dollar-denominated energy-only price as a constant rate.

Limitations

  • The Green Grid defines PUE using energy over a common period; this calculator uses power inputs and cannot verify that the measurement intervals or meter boundaries truly match.
  • The annual estimate does not model seasonal or load variation, meter-boundary errors, demand charges, taxes, or other tariff terms.
  • This is not an audited annual PUE, engineering design, equipment selection, or compliance result.

Sources

Planning estimate only. This is a power-based calculation from user-entered values, not an energy-metered PUE or a substitute for verified operating data and engineering review.

LoadCairn / Facility efficiency guide

How to calculate PUE and DCiE.

Review how the LoadCairn planning calculator compares total facility power with IT load, what its optional annual estimate assumes, and where the calculation stops.

Open the PUE & DCiE calculator

Calculation method

Power inputs / planning only

  • PUE = total facility power ÷ IT load
  • DCiE (%) = IT load ÷ total facility power × 100 = 100 ÷ PUE
  • Non-IT overhead (kW) = total facility power − IT load

PUE compares facility power, the numerator, with IT load, the denominator. In this calculator, DCiE is the reciprocal percentage calculation shown above; it is not a separate benchmark claim.

Illustrative example · not a target or industry benchmark

500 kW facility ÷ 400 kW IT = PUE 1.25

400 kW IT ÷ 500 kW facility × 100 = DCiE 80%

500 kW facility − 400 kW IT = 100 kW non-IT overhead

These match the calculator’s editable starting values and demonstrate the arithmetic only.

01 / Inputs and assumptions

Match the measurement basis

The calculator uses entered power values for a planning comparison. Its optional annual energy and cost estimates extend those inputs with fixed assumptions.

02 / Limitations

A planning estimate, with boundaries

03 / Further reading

PUE source references

These references discuss PUE and its measurement. DCiE on this page is the calculator’s reciprocal calculation.

04 / Run an estimate

Explore your own inputs

Adjust facility power and IT load in the browser, then review the calculation trace and planning assumptions.

Try the PUE & DCiE calculator

Facility efficiency / Benchmarks

Typical PUE ranges

These indicative planning bands are synthesized from published reference points, not a classification or universal standard. They are not guarantees: climate, IT utilization, redundancy, measurement boundary, and reporting period affect results. Use measured site data for decisions.

Legacy enterprise data center

PUE 1.8–2.2

A planning band around the roughly 2.0 reference reported for older, less efficient enterprise facilities; cooling and electrical overhead can approach the IT load.

Average colocation

PUE 1.5–1.8

A broad midrange around published non-hyperscale averages. Shared-facility climate, utilization, and meter boundaries can move an individual site outside it.

Efficient modern build

PUE 1.2–1.4

A newer, well-operated facility may approach or beat 1.3, but the result depends on climate, load, and design choices.

Hyperscale

PUE 1.1–1.2

Large operator fleets have reported averages in this neighborhood; one company’s fleet result is not a promise for every site.

Source context: the U.S. Department of Energy guide describes 1.6 as average and 1.4/1.1 as “good” / “better” examples; a 2026 Focus on Energy evaluation summarizes older enterprise sites around 2.0, non-hyperscale sites around 1.7, and hyperscale averages around 1.1–1.2. Uptime Institute reports that new, larger facilities routinely achieve 1.3 or lower, and Google reports a 1.09 global fleet average for 2025. The bands above are rounded working ranges around those references.

Facility efficiency / Reciprocal metric

DCiE: the reciprocal of PUE

Data Center Infrastructure Efficiency (DCiE) expresses the IT share of total facility energy as a percentage. It reverses PUE’s ratio: as PUE falls, DCiE rises.

DCiE = 1 / PUEDCiE (%) = 100 / PUE

Formula and measurement context: The Green Grid’s PUE guidance and the U.S. Department of Energy guide.

PUEDCiE
2.050%
1.567%
1.471%
1.377%
1.283%
1.191%

Percentages are rounded to the nearest whole percent from (100 ÷ PUE). The reciprocal relation and measurement caveats follow the U.S. Department of Energy guide and The Green Grid’s PUE guidance.

Facility efficiency / Worked example

Estimate annual overhead cost

This fixed-input example assumes a constant operating load for a non-leap year and an energy-only electricity rate. It prices facility overhead, not the IT load or total facility energy.

Illustrative planning estimate · assumed inputs

  1. Total facility power600 kW
  2. IT load500 kW
  3. PUE = total facility power ÷ IT load600 kW ÷ 500 kW = 1.20
  4. Non-IT overhead = facility power − IT load600 kW − 500 kW = 100 kW
  5. Assumed annual hours and energy-only rate8,760 h/year · $0.12/kWh
  6. Annual overhead cost100 kW × 8,760 h/year × $0.12/kWh= $105,120/year

Assumptions: the 600 kW facility draw and 500 kW IT draw remain constant for 8,760 hours; $0.12/kWh is a sample energy-only rate, not a quoted tariff. The cost excludes demand charges, taxes, and other tariff terms. Annual overhead energy is 100 kW × 8,760 h = 876,000 kWh, so the cost uses non-IT energy rather than total facility energy.

Facility efficiency / Component examples

Illustrative facility scenarios

Each row is a synthetic planning example, not measured data from a named facility. The assumed categories are non-overlapping: total facility power = IT load + cooling + power distribution losses + lighting/other load; PUE = total facility power ÷ IT load.

Small enterprise room

IT load
80 kW
Cooling
55 kW
Power-distribution losses
12 kW
Lighting / other
8 kW
Facility total
155 kW
PUE
1.94

Colocation hall

IT load
500 kW
Cooling
170 kW
Power-distribution losses
45 kW
Lighting / other
25 kW
Facility total
740 kW
PUE
1.48

Efficient modern build

IT load
1,000 kW
Cooling
160 kW
Power-distribution losses
75 kW
Lighting / other
35 kW
Facility total
1,270 kW
PUE
1.27

Hyperscale hall

IT load
5,000 kW
Cooling
450 kW
Power-distribution losses
250 kW
Lighting / other
100 kW
Facility total
5,800 kW
PUE
1.16

High-density compute hall

IT load
1,200 kW
Cooling
220 kW
Power-distribution losses
85 kW
Lighting / other
35 kW
Facility total
1,540 kW
PUE
1.28

Scenario arithmetic is derived directly from the displayed component loads and rounded to two decimal places. These estimates do not specify equipment, redundancy, or a real site’s operating performance.

Related planning tools

Facility efficiency / FAQ

PUE questions and answers

What is a good PUE for a data center?

There is no universal target. A lower PUE means less facility overhead per unit of IT power, but compare sites only with matching meter boundaries, reporting periods, climates, and operating loads. Published ranges are context, not a design guarantee.

Can PUE be below 1.0?

No, not under the standard PUE boundary with complete, consistent measurements. Total facility energy includes IT energy plus overhead, so PUE is at least 1.0. A result below 1.0 usually points to mismatched meters, boundaries, units, or time periods.

What is the difference between PUE and DCiE?

PUE is total facility energy divided by IT energy. DCiE is IT energy divided by total facility energy, expressed as a percentage. They are reciprocal views of the same relationship: DCiE (%) = 100 / PUE.

How often should PUE be measured?

Use matching facility and IT meter intervals, ideally from continuous interval data, then report a clearly stated period such as a month or year. Consistent boundaries and an energy-based period make seasonal and load changes easier to compare.

Does a low PUE mean a data center is efficient overall?

No. PUE measures facility overhead relative to IT energy; it does not show how much useful computing the IT equipment delivers, or measure water use, carbon impact, or reliability. Review workload efficiency and other operating metrics too.

What is partial PUE?

Partial PUE (pPUE) applies the PUE ratio to a defined portion of a data center, such as one data hall, using the facility energy serving that scope divided by that scope’s IT energy. State the boundary and do not compare it directly with a whole-site PUE unless the scopes match.

All benchmark and example values are planning estimates. They do not replace a licensed engineer’s design, verified meter data, or manufacturer specifications.