AI & sustainability
Prompt Carbon Index
Make the CO₂ footprint of AI prompts visible.
Generative AI uses computing power every time it runs. The Prompt Carbon Index from Institute for AI helps you make sense of the associated CO₂ footprint and see how estimates vary with the model and token count.
AI and sustainability
Responsible AI use covers data protection, governance and legal requirements.
It also means paying attention to the resources behind digital technology.
The Prompt Carbon Index helps people understand and put the environmental footprint of AI use into context.
- Transparency
- Make the less visible impacts of AI use easier to see.
- Context
- Make CO₂ figures easier to understand through familiar comparisons.
- Informed use
- Make considered choices about how to use AI.
Make the footprint visible
Start an analysis in one click. The Prompt Carbon Index shows you:
- estimated CO₂ emissions per prompt
- differences between AI models
- comparisons with everyday activities
- the effect of different prompt lengths
Select EN in the calculator for its English interface. The calculator asks for an email address if you want to receive the detailed report.
Features at a glance
- Quick calculation
- Paste a prompt or enter a token count to start the analysis.
- Model comparison
- Select different AI models and see how their estimated CO₂ profiles differ.
- Everyday comparisons
- Put CO₂ figures into context with comparisons such as driving a car or using a desktop computer.
- Transparency
- See how model choice and prompt length affect the result.
An illustrative calculation
In this example, a 92-token GPT prompt comes to 0.30 grams of CO₂. That is roughly equivalent to driving a car for two metres.
The figure is illustrative. The calculator provides estimates.
From idea to tool
We first spoke publicly about the CO₂ impact of AI at the Green Peak Festival in 2025. That conversation became the starting point for this tool.
Anyone who uses AI should be able to understand the resources it takes to run it.
Green Peak Festival 2025- Our vision
- Transparency is the first step towards responsible use.
- Our approach
- Understanding technology includes making its impacts visible.
- Our contribution
- Bring education and awareness together.
Lilia Schraut
Vibe Coding Specialist
Developer of the Prompt Carbon Index
Prompt Carbon Index for organisations
Businesses and education providers can use the Prompt Carbon Index as a starting point for further analysis.
- Understand usage patterns
- Compare models
- Document AI use transparently
- Build awareness of resource-efficient use
- Identify practical recommendations
Test. Understand. Apply.
Explore the CO₂ footprint of your own prompt.
Start the Prompt Carbon Index