Estimated · ML.ENERGY 2025

Claude Water Footprint

Formula v1.3.1 · ML.ENERGY 2025 · ±50%
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How we calculate — ML.ENERGY Leaderboard v3.0 · NeurIPS 2025

Formula chain

Water flows through: effective token count → model multiplier → water rate (low / mid / high). All three scenarios are always reported — never just one number.

effective_tokens = (output_tokens × 1.000) // autoregressive decode — formula baseline + (fresh_input_tokens × 0.200) // pricing proxy: $3 / $15 MTok + (cache_creation_tokens × 0.250) // pricing proxy: $3.75 / $15 MTok + (cache_read_tokens × 0.001) // floor value — see note below scaled_tokens = effective_tokens × model_multiplier water_mL = scaled_tokens × rate // three scenarios

Water rates (mL / effective token)

ScenarioRateWUEBasis
Low (optimistic)0.0000360.18 L/kWhAWS modern, cool climate
Mid (central) ✶0.000361.8 L/kWhML.ENERGY 2025 US average
High (pessimistic)0.000794.0 L/kWhHot climate, older facility

✶ Charts and main values show mid. The low–high band reflects WUE uncertainty across different data centre locations. Anthropic does not disclose which AWS regions handle inference.

Model multipliers (pricing-derived, verified 2026-06-12)

ModelOutput priceMultiplier
Haiku 4.5$5/MTok0.33×
Sonnet 4.5$15/MTok1.00×
Sonnet 4.6 (baseline)$15/MTok1.00×
Opus 4.5–4.8$25/MTok1.67×
Fable 5 / Mythos 5$50/MTok3.33×

Multipliers are derived at calculation time as model output price ÷ baseline ($15). Pricing includes margin, so treat multipliers as ±factor-of-2. Verified against the live Anthropic models documentation on 2026-06-12. Directional accuracy (Haiku < Sonnet < Opus < Fable) holds; absolute magnitudes carry the ±50% uncertainty. Models not in the table fall back to the Sonnet baseline (1.00×).

Empirical anchor (v1.3)

ML.ENERGY Leaderboard v3.0 (Dec 2025): Llama 3.1 70B FP8 on 8×H100 = 0.39 J/output token (GPU, measured via NVML). Apply 1.82× server overhead (GPU ≈ 55% of DGX H100 TDP) → 0.71 J/token at IT load. At US average WUE (1.8 L/kWh): 0.71 ÷ 3,600,000 × 1800 = 0.00036 mL/token (mid rate). Llama 70B is used as the closest publicly-measured proxy for Claude Sonnet — Anthropic does not disclose its hardware or energy use.

Prior anchor (Li et al. 2023, GPT-3 era): 0.014 mL/token — 39× higher. The paper's lead author confirmed (2026-05-31) those estimates should not be applied to modern models. See methodology.md for the full correspondence.

Note on cache_read weight (0.001×)

The pricing proxy gives ~0.02× ($0.30/$15 MTok). At that weight, cache reads dominate long-context Claude Code sessions. The 0.001 floor prevents dominance while acknowledging that some compute is involved. A v2 formula will introduce a cache_size × output_tokens cross-term. The deviation from the pricing proxy is documented in formula.json and absorbed by the ±50% accuracy band.

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