ChatGPT energy use calculator
OpenAI says an average ChatGPT query uses about 0.34 watt-hours. That is small for one message and adds up over a year of daily use.
This calculator turns your daily prompts into watt-hours and compares the total with things you already know.
Result
2.48 kWhEnergy per year
- Energy per day
- 6.8 Wh
- Energy per month
- 207 Wh
- Full phone charges per year
- 165
- Hours of one LED bulb per year
- 248
- Litres of water boiled per year
- 22.6
These are estimates. Real figures depend on the model, the data center and the length of the answer.
How this is calculated
- OpenAI (2025). Sam Altman states an average ChatGPT query uses about 0.34 Wh and 0.32 mL of water. blog.samaltman.com
- Google (2025). A median Gemini text prompt uses 0.24 Wh, 0.03 g CO2e and 0.26 mL of water. arxiv.org
- IEA, Electricity 2024. Earlier estimate of 2.9 Wh per ChatGPT request, used here as the high case. iea.org
- Our assumptions. A phone charge is 15 Wh, an LED bulb is 10 W, boiling one litre of water takes 110 Wh, a petrol car emits 120 g CO2 per km.
Questions
How much energy does ChatGPT use per query?
OpenAI gives 0.34 Wh for an average query. Google reports 0.24 Wh for a median Gemini text prompt. An older estimate quoted by the IEA was 2.9 Wh.
Is that a lot?
One prompt is roughly two minutes of a 10 W LED bulb. Twenty prompts a day for a year come to about 2.5 kWh with the typical estimate, which is about 165 phone charges.