Simon Willison’s Weblog

In June 2025 Sam Altman claimed about ChatGPT that "the average query uses about 0.34 watt-hours".

In March 2020 George Kamiya of the International Energy Agency estimated that "streaming a Netflix video in 2019 typically consumed 0.12-0.24kWh of electricity per hour" - that's 240 watt-hours per hour at the higher end.

Assuming that higher end, a ChatGPT prompt by Sam Altman's estimate uses:

0.34 Wh / (240 Wh / 3600 seconds) = 5.1 seconds of Netflix

Or double that, 10.2 seconds, if you take the lower end of the Netflix estimate instead.

I'm always interested in anything that can help contextualize a number like "0.34 watt-hours" - I think this comparison to Netflix is a neat way of doing that.

This is evidently not the whole story with regards to AI energy usage - training costs, data center buildout costs and the ongoing fierce competition between the providers all add up to a very significant carbon footprint for the AI industry as a whole.

(I got some help from ChatGPT to dig these numbers out, but I then confirmed the source, ran the calculations myself, and had Claude Opus 4.5 run an additional fact check.)