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How much energy does GPT-5.2 Pro use?

OpenAI · released 2025-12-11

GPT-5.2 Pro uses about 31.2 Wh of electricity to answer a typical question. A long, complex answer costs about 23× more, at 728 Wh. That places it 264 of 266 among the models we can measure, and every figure here is calculated the same way as every other model.

A typical question
31.2 Wh
≈ 58 metres of driving
A long, complex answer
728 Wh
≈ 1.3 km of driving
Capability
155.4
Energy rank
264 of 266

How capable is it, really?

The capability figure of 155.38 is a composite over 58 benchmarks — Epoch AI's Capabilities Index, which folds in software engineering, agentic tool use, long-context comprehension and creative writing as well as science reasoning. It is one number standing for a lot of separate tests, so treat a small gap between two models as noise rather than a ranking.

No human head-to-head votes exist for this model. It has been benchmarked but not, as far as we can tell, put in front of people to compare against anything else — worth knowing before treating its scores as a verdict on its answers.

What this figure is

Day-one estimate  Calculated from an estimated parameter count — the maker hasn't published one. Every model on this site is calculated the same way, so the comparison holds even where the absolute value carries uncertainty. Our figures are good to roughly a factor of two to three, which is why we only ever state a difference of 5× or more.

The figure above is an understatement. GPT-5.2 Pro generates reasoning text you never see, and that text costs energy to produce. Our calculation counts a fixed answer length, so the real figure is higher — we cannot say by how much, because the amount is not published.

Is there a better choice?

A lighter model that does the job
OpenAI · capability 159.1. It scores higher than GPT-5.2 Pro on Epoch's Capabilities Index (159.12 against 155.38), the composite over 58 benchmarks that the capability figure above comes from, and uses about 32× less energy per answer: 22.5 Wh against 728 Wh.

What OpenAI publishes

Energy cannot be worked out without knowing how big a model is. Of the 36 models from OpenAI that we track, 27 can be assessed at all — the rest publish too little for anyone outside the company to calculate anything.

Where these figures come from

Capability and the roster come from Epoch AI, whose Capabilities Index is the 58-benchmark composite quoted above. Energy is calculated with EcoLogits and calibrated against laboratory measurements from ML.ENERGY. Human preference comes from LMArena. All four are public and free; the full method is here.

These figures are published under CC BY 4.0 — use them anywhere, including commercially, with credit to The AI Footprint.

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Figure calculated 2026-09-20 · how these numbers are made · the full comparison of 266 models