The AI Footprint ← All 266 models

How much energy does Gemini 2.5 Flash use?

Google DeepMind · released 2025-06-17

Gemini 2.5 Flash uses about 0.301 Wh of electricity to answer a typical question. A long, complex answer costs about 23× more, at 7.02 Wh. That places it 192 of 266 among the models we can measure, and every figure here is calculated the same way as every other model.

A typical question
0.301 Wh
under a metre of driving
A long, complex answer
7.02 Wh
≈ 13 metres of driving
Capability
140.0
Energy rank
192 of 266
Human votes
1417

How capable is it, really?

The capability figure of 139.97 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.

122,732 people have voted on it in blind head-to-head comparisons on LMArena, giving it a rating of 1417. This is the only figure here that measures whether anyone actually prefers the answers, rather than how the model scores on a test. Broken down, people rate it 1423 on coding, 1402 on creative writing, 1405 on following instructions.

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. Gemini 2.5 Flash 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
Alibaba · capability 146.5. It scores higher than Gemini 2.5 Flash on Epoch's Capabilities Index (146.49 against 139.97), the composite over 58 benchmarks that the capability figure above comes from, and uses about 20× less energy per answer: 0.351 Wh against 7.02 Wh. It has not faced human head-to-head voting, where Gemini 2.5 Flash carries 122,732 votes — worth weighing. See them side by side →

What Google DeepMind publishes

Energy cannot be worked out without knowing how big a model is. Of the 27 models from Google DeepMind that we track, 18 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.

Compare it with something

Share this

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