OpenAI's only footprint figure: one sentence in a CEO blog post

In "The Gentle Singularity", Sam Altman offered the first official numbers for ChatGPT's footprint: about 0.34 watt-hours per average query — "about what an oven would use in a little over one second" — and about 0.000085 gallons of water, "roughly one fifteenth of a teaspoon".

The figures are consistent with Epoch AI's independent estimate of roughly 0.3 Wh for a typical GPT-4o query, but the post provides no methodology, no definition of an average query, no treatment of long inputs (Epoch estimates 2.5 Wh at 10k tokens and almost 40 Wh at 100k) and no training footprint. At OpenAI's scale — hundreds of millions of weekly users — the per-query framing understates the total.

The index treats the figure as disclosed but unverified and caps the efficiency score accordingly.