AI Energy & Water Use per Query (2026): What One AI Prompt Actually Costs

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Technical Performance · Index

AI Energy & Water Use per Query 2026

A single AI text prompt uses roughly 0.2–0.3 watt-hours of electricity — far less than the alarming numbers that circulated in 2023, but the fleet-level total is what’s exploding. Every figure is linked to its primary source and dated.

By The AI Index · Updated · 5 min read · 6 sourced figures

Key takeaways

  • ~0.24 Wh per prompt. Google’s Aug 2025 report puts a median Gemini text prompt at 0.24 Wh; Sam Altman cited ~0.34 Wh per ChatGPT query; Epoch AI estimates ~0.3 Wh for GPT-4o. (Google / Altman / Epoch)
  • Water is tiny per query, big at scale. Google reports ~0.26 mL per prompt; the totals add up across billions of queries. (Google)
  • The macro number that matters. The IEA puts data-center electricity at ~415 TWh in 2024, rising to ~945 TWh by 2030 — roughly a doubling, with AI the main driver. (IEA)
  • “Methodology wars.” Per-query estimates vary 10×+ depending on model size, PUE, grid mix, and whether one-time training is counted — treat any single figure with caution.

0.24 Wh

per median text prompt (Google)

~945 TWh

data-center electricity by 2030 (IEA)

0.26 mL

water per prompt (Google)

Per-query energy estimates compared

The headline figures cluster around 0.2–0.3 Wh — close to a Google web search — but an older, widely-circulated estimate of 2.9 Wh per query (from 2023–24) is roughly 10× higher. The gap is the “methodology war” in a single chart: Google’s Gemini at 0.24 Wh, Epoch’s GPT-4o estimate at ~0.30 Wh, and Sam Altman’s ~0.34 Wh figure for ChatGPT all sit near a reference Google search (~0.30 Wh), while the older estimate towers over them.

SourceWatt-hours per query
Google Gemini (2025)0.24
Epoch GPT-4o est.0.30
ChatGPT — Altman0.34
Google search (ref.)0.30
Older 2023–24 est.2.90
Watt-hours per query, by source. Sources: Google, Epoch AI, Altman.

“Each query is cheap; the fleet is not. The real story is data-center demand more than doubling by 2030.”

Why the estimates disagree so much

Model size & routing. A small distilled model costs a fraction of a frontier model; “per query” hides which model answered. Boundary choices — some figures count only the GPU; others add cooling, networking, idle capacity, and data-center overhead (PUE). Training vs inference — training is a large one-time cost; amortizing it across queries changes the per-query number dramatically. And grid & location: a query on a coal-heavy grid emits far more CO₂ than the same query on hydro — even at identical energy use.

The numbers in full

MetricValueSource & date
Energy, median Gemini text prompt0.24 WhGoogle, Aug 2025
Water, median Gemini text prompt0.26 mLGoogle, Aug 2025
Energy, ChatGPT query~0.34 WhSam Altman, Jun 2025
Energy, GPT-4o query (est.)~0.3 WhEpoch AI
Data-center electricity, 2024 → 2030~415 → ~945 TWhIEA, 2025
GPT-3 training emissions (one-time)~552 tonnes CO₂Patterson et al., 2021

Per-query vendor figures are self-reported and exclude some lifecycle stages; agency/peer-reviewed figures (IEA, Patterson) carry higher confidence. Sources: Google, Altman, IEA.

Frequently asked

How much energy does one AI prompt use?

Current vendor and research estimates cluster around 0.2–0.3 watt-hours for a typical text prompt — Google reports 0.24 Wh, Sam Altman cited ~0.34 Wh, and Epoch AI estimates ~0.3 Wh. That’s comparable to a Google search and far below older 2.9 Wh estimates. (Google / Altman / Epoch)

If each query is small, why the concern?

Scale. The IEA projects data-center electricity roughly doubling to ~945 TWh by 2030, with AI the main driver. Billions of queries plus training and idle capacity add up even when each query is cheap. (IEA)

How much water does an AI prompt use?

Google reports about 0.26 mL per median Gemini text prompt — a fraction of a millilitre per query, though the totals add up across billions of queries and during training. (Google, Aug 2025)

Cite this page

The AI Index (2026). AI Energy & Water Use per Query 2026. Retrieved Jun 20, 2026, from report-ai.org/indexes/technical-benchmarks/ai-energy-water-per-query/

Related: Technical Performance · Compare year over year · Large Language Model · Tokens

On this page

Primary sources

  • Google — technical report, Aug 2025 · 0.24 Wh · 0.26 mL per prompt
  • IEA — Energy & AI, 2025 · 415 → 945 TWh by 2030
  • Altman / Epoch / Patterson — ~0.34 Wh · ~0.3 Wh · GPT-3 training CO₂

10×

Gap between current ~0.24 Wh estimates and the older 2.9 Wh per-query figure — the “methodology war” in one number.

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