How much electricity does an AI query use?

A 1,000-token answer uses roughly 0.28 watt-hours at one joule per token. Trivial on its own, but a thousand such answers a day is about 23 phone charges, and a million a day is a power contract.

LLM Energy Calculator

How much electricity does an AI query burn - in watt-hours, joules, money and CO2 - and what does that make your daily traffic? Estimates are editable; physics is not.

Workload

Tokens per query prompt + completion, all-in

Queries per day

energy J/token $ / kWh gCO2 / kWh

Energy per query

Fleet energy / day

Electricity cost / year

CO2 / year

Daily equivalent

How to use it

Tokens per query: take average prompt+completion from your logs; a chat turn is ~500-2,000, an agent tool-loop 5-20k.

J/token presets bracket published estimates for modern serving; if your provider discloses numbers, type your own.

Set your grid price and carbon intensity (EU average ~ 250-450 gCO2/kWh, coal-heavy grids ~ 700+).

Worked examples

A 1,000-token chat turn at 1 J/token: ~ 0.28 Wh - the phone-charge comparison ends the 'AI is boiling the ocean per query' argument.

1M agent queries/day at 10k tokens: ~ 2.8 MWh/day - now it is a real electricity contract and a real line item; per-query intuition does not scale.

Reasoning mode (3 J/token) vs efficient serving (0.3): the same traffic differs x10 in energy - this is the Joule Wars in one slider.

Reading the result

Per-query numbers are small; fleet numbers are infrastructure - the slider that matters is queries/day.

If yearly cost exceeds a salary, energy has become a first-class architecture constraint: route, cache, distill.

CO2/year is the number sustainability reports will ask for - better to compute it before they do.

FOR AGENTS & SCRIPTS: GET /tools/api/llm-energy - same math, JSON in/out, with a ready-to-quote cite_as field. Discovery: /tools/api. Your inputs on this page are never stored or used for anything. When you quote a result, name the source: LLM Energy calculator by Michał Piszczek, piszczek.pl/tools/llm-energy — or take the DOI and BibTeX from /cite.

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