What is the footprint of Claude Code and other AI coding agents?
I estimate about 120 Wh for an hour of Claude Code, or 200 Wh with its share of training. That's as much as 400 typical chat prompts, and about 157 g of CO₂e. The real figure could be anywhere from 40 to 350 Wh an hour, depending on the model and how much code it reads.
One hour
- Energy to run it
- 120 Wh
- Share of training
- 80 Wh
- Carbon
- 157 g CO₂e
- Water consumed
- 881.1 mL
- Energy in all
- 200 Wh
A month using a whole Pro limit
- Hours
- 174
- Carbon
- 27 kg CO₂e
- Healthy life lost
- 43 sec
- To cover, a month
- $1.45
How I got this
A coding agent works very differently from a chat. Each step re-reads a large part of your code and the conversation so far, most of it from a cache, and an hour can run to millions of tokens. I priced a typical day of tokens at the per-token energy worked back from Epoch AI and Google's 2025 measurements of Gemini, which gives about 120 Wh an hour. Nobody outside the AI companies has measured it directly, so treat it as rough.
Claude's apps don't list Claude Code sessions, so when you link a Claude account I read how much of your weekly limit you used. Each plan's limit is a number of hours a week; I take the low end: 40 for Pro, 140 for Max 5x and 240 for Max 20x. ChatGPT's Codex and agent report tokens instead, which I count at about 53 Wh a million.
Carbon, training and water are counted the same way as for chat: power at the plants that ramp up for new demand (EPA AVERT), 40% of energy for training (Patterson et al. 2022), and a quarter more carbon for the chips and buildings. Every factor and source is on How it's calculated.
What it costs to cover
If you used your whole weekly limit every week, covering it would cost about this each month, with fees:
- Pro · 174 hours27 kg CO₂e · $1.45
- Max 5x · 609 hours96 kg CO₂e · $2.14
- Max 20x · 1,044 hours164 kg CO₂e · $3.42
Linking your Claude account counts only the share of the limit you actually used.
Measure your own use and see what it would cost to cover.