UsesLevel 3 of 6 useUse, level 3 of 6Calculated with 2 entries, levels 1 and 3Database structure 
6Territories
5Organisations
4Occupations and activities
2Machine operations
1Calculation factorsQuestion to Claude, Projet Celsius estimate
A question written to Claude and its answer of about half a page. Projet Celsius estimate.
- The calculation covers computing the answer on the servers and cooling the data centre.
- 100% of the calculation rests on database assumptions; it does not measure actual use.
- Out of scope: the manufacturing of servers and chips, model training, the internet network and the user's device.
Sentence to citeQuestion to Claude, Projet Celsius estimate: 0.14 gCO2e per question, for 0.3 Wh of electricity, servers worldwide (458 gCO2e/kWh).
- Calculated with
Breakdown of emissions by item
0.14 gCO2e in total: 0.3 Wh of electricity × 458 gCO2e/kWh (servers worldwide).
Inputs of the calculation
PUE of the data centre, Read 1,000 tokens, Write 1,000 tokens
How the calculation is built
Calculated like the database's quick question, Sonnet, offered with Haiku in the free plan, being placed in the medium class. Anthropic publishes neither the electricity of its responses nor the size of its models, and the class selected for each is a Projet Celsius assumption.
Comparison with the other uses
↓ The heaviest use in the topic, "Deep research": 45 gCO2e, 330 times more
Emissions of one use, linear scale, 7 of the 21 uses in the topic. For calculated values, servers worldwide.
Characteristics
| Unit | 1 question |
|---|---|
| Default location | world, 458 gCO2e/kWh (Ember 2025, life cycle); 11 other locations to choose from |
| Counted | the computation of the answer on the servers and data centre cooling |
| Not counted | the manufacturing of servers and chips, model training, the internet network and the user's device |
| Status | estimated, 2 other published values |
All the characteristics
| Identifier | IA-0230, projetcelsius.com/en/ai/database/IA-0230/ |
|---|---|
| Version | 0.1 of 13 November 2026 |
| Category | Uses, a request to AI |
| Choice of the selected value | database calculation from the entries this one is made of, at the quantities of the unit |
| Sources | calculation of the database |
| Licence | CC BY 4.0 |
Usage parameters
Advanced settings
Result for the chosen case
For a carbon footprint
| Item | purchases of services (GHG Protocol scope 3, category 1); regulatory BEGES, category 4 |
|---|---|
| Quantity | 1 question |
| Factor | 0.14 gCO2e per question, IA-0230 version 0.1, based on the local grid (location-based), servers worldwide |
| Total | 0.14 gCO2e · not counted: the manufacturing of servers and chips, model training, the internet network and the user's device |
Breakdown by item
Quantity, unit value, contribution and nature of the data for each item
| Item | Quantity | Unit value | Contribution | Share | Nature of the data |
|---|---|---|---|---|---|
| Quick question | × 1 | 0.3 Wh | 0.3 Wh | 100 % | assumption |
Entries that use it
No other entry in the database is calculated from this one.
Sources of the calculation
7 publications, for this entry and those used to calculate it, with the chosen parameters.
The result is calculated by Projet Celsius. The sources below support its uses, its factors and its conversion; they do not all measure this total.
Uses and assumptions
These publications shed light on AI tasks and uses. They do not measure the carbon footprint of the case calculated.
Anthropic · November 2026
Role and limits : Anthropic
What the publication covers. price and relative use of the Free, Pro, Max and Ultra plans
What it does not cover. any number of messages or tokens
Reading by the database. Page read on 2 November 2026; no quantified cap
Question to Claude → : Quick question →
The database's quick question, 100 tokens read and 400 written, put to the chosen model; Anthropic does not publish the size of its models, so the class of each is an assumption
Scope of the figure used. computation of the response, data centre
Limit. The quantity and the share entrusted to AI are database assumptions, not a measured footprint.
Energy and factors
The references of the selected values and of the entries used in this calculation.
Epoch AI · February 2025
Role and limits : Epoch AI
What the publication covers. the calculation from the hardware and the assumed size of the model
What it does not cover. actual measurements
Reading by the database. A public, transparent calculation
Reference of the selected value
Scope of the figure used. GPT-4o, 500 tokens written, full scope
Limit. A public calculation, from the hardware and the assumed size of the model
Role and limits : Google
What the publication covers. chips, host, standby machines, data centre, on-site water
What it does not cover. manufacturing, training
Reading by the database. The only production measurement published by a provider
Reference of the selected value
Scope of the figure used. Median of a text prompt; chips, host, standby machines, data centre
Limit. The only production measurement published by a provider, not audited by a third party
Microsoft Research · 2026
Estimation de l'énergie des requêtes en production (Joule) ↗ (new tab)
Role and limits : Microsoft Research
Author. Microsoft Research, Oviedo et al.
What the publication covers. H100 nodes, production
Reading by the database. Calibrated on production
Reference of the selected value
Scope of the figure used. Median, 500 tokens read and 300 written, H100 nodes
Limit. Not a measurement, but calibrated on production; judges public estimates to be 4 to 20 times too high
OpenAI · June 2025
Role and limits : OpenAI
Author. Sam Altman, OpenAI
What the publication covers. an average query
What it does not cover. method, scope
Reading by the database. One sentence, no method
Reference of the selected value
Scope of the figure used. "An average query", with no published method
Limit. No published scope; consistent with Google
Watershed · Aug. 2026
Estimating GHG Emissions from AI Use: Framework for Corporate-Level Measurement ↗ (new tab)
Role and limits : Watershed
Author. Bistline, Ulissi, Davis, Glidden, Joyce, Li, Mohsenin and Suh (Watershed)
What the publication covers. factors per 1,000 tokens read and written at the server before PUE (host and standby machines included), PUE separate (1.10 for a large operator, 1.56 for an unknown operator)
What it does not cover. clean measurements, the model and the hardware
Reading by the database. Default factors proposed for review (public data as of June 2026); for a large operator, taken from Google's measurement published in 2025 (Elsworth et al.), which already contains the data centre overhead; constant per token, they underestimate long contexts and agents according to the authors
Reference for the variant "Medium model, Watershed default factor"
Scope of the figure used. Default factor for 1,000 tokens read, medium model, large operator, at the server before PUE (Watershed table 2, public data as of June 2026)
Limit. A default value that Watershed derives from Google's measurement (0.24 Wh for the median text query of the Gemini app), with about 500 tokens per query and a written token costing 3 times a read token; Watershed does not give the split between read and written tokens. The 0.24 Wh already include the overhead of Google's data centre (0.02 Wh, 8%): with 375 tokens read and 125 written, the simplest reading, the factor contains it, and the PUE of 1.10 applied afterwards counts it a second time (about 9%). Values proposed for review, final at the next version of the framework
Reference for the variant "Medium model, Watershed default factor"
Scope of the figure used. Default factor for 1,000 tokens written, medium model, large operator, at the server before PUE (Watershed table 2, public data as of June 2026)
Limit. 3 times the reading factor, based on the ratio between writing and reading selected by Watershed (Patel et al., Splitwise, 2024). Same derivation and same caveat as for reading: Google's 0.24 Wh already include about 8% of data centre. Values proposed for review, final at the next version of the framework
Quick question → : Data centre PUE →
The data centre, convention C3
Scope of the figure used. building cooling and losses
Limit. This figure covers part of the calculation; it does not measure the whole entry.
Reference of the selected value
Scope of the figure used. Default factor for a large operator, from the server to the data centre; 1.56 for an unknown operator
Limit. A default value, not a measurement
Conversion into carbon
The source of the electricity factor of the selected location.
Worldwide: 458 gCO2e/kWh, life cycle.
Role and limits : Ember
Author. Ember, Our World in Data
What the publication covers. electricity generation over the life cycle, by country
What it does not cover. guarantees of origin
Reading by the database. The same source for all countries
Conversion of electricity into carbon: worldwide
Scope of the figure used. the production of electricity over the life cycle, including power plant construction and fuels
Limit. An average for the chosen country, not the electricity contract or the data centre of a specific service.
Published values
2 figures for the same operation, each within its own scope.
| Source | Date | Electricity | What the figure measures | Scope | Status |
|---|---|---|---|---|---|
| Question to Claudeselected by the database, v0.1 | 2026 | 0.3 Wh | the value selected by the database | same scope | estimated |
| Jegham et al. ↗How Hungry is AI? Benchmarking Energy, Water, and Carbon Footprint of LLM Inference | 2025 | 0.95 Wh | Claude 3.7 Sonnet, short question of 100 tokens read and 300 written, data centre included; model classed as large by the authors' assumption, on 8 GPUs | other scope | estimated |
| Jegham et al. ↗How Hungry is AI? Benchmarking Energy, Water, and Carbon Footprint of LLM Inference | 2025 | 0.975 Wh | Claude 3.5 Haiku, same short question, same hardware assumption | other scope | estimated |
The published figures do not all count the same scope; the scope of each figure is written next to it. Why do the estimates diverge?
Nature of the data
Published readings, conventions, assumptions
- Projet Celsius assumptions 100 %
Calculation assumptions
Quantities, nature and source of each assumption
Quick question : counted 1 times
The database's quick question, 100 tokens read and 400 written, put to the chosen model; Anthropic does not publish the size of its models, so the class of each is an assumption
Methodology conventions
With their alternatives
| The standard query | A query counts 100 tokens read and 400 written |
|---|---|
| The data centre | Server electricity is multiplied by 1.10 for the data centre |
| The default location | Without other information, the servers are in the world, at the world average electricity |
| Electricity, location-based, on a life cycle basis | The kilowatt-hour is that of the servers' country, on a life cycle basis, from a single source for all countries |
| Two significant figures | A calculated value is rounded to two significant figures, a published value is reproduced with the precision of its source; the calculation keeps full precision |
| The formula | the sum of what makes up the entry, then CO2e: electricity (Wh) multiplied by the carbon intensity of the server location (gCO2e/kWh), divided by 1,000 |
| Calculate a case without an entry | The formula, the default values and a step-by-step example |
History
Entry in version 0.1 of 13 November 2026, in the database in version 0.4
- 13 November 2026Version 0.1 of the entry, as of the date of its current value.
- 31 October 2026Creation of the database, in its first version (0.1).
