CarbonWatch
The questions that keep coming up about the estimate, privacy, and what the figures are worth. Every answer stands on its own.
How much CO₂ does one AI request cost?
A 500-token answer — about 350 words — costs roughly 2 Wh of electricity under the CarbonWatch model. That is 0.38 gCO₂e if the service computes in the United States, 0.05 g if it computes in France, 0.58 g in China: the gap comes from the electricity grid, not from the model. For comparison, one kilometre in a petrol car emits about 120.
Does a model running on my own machine pollute less?
Not necessarily, and CarbonWatch does not settle it: it counts both separately. A local model is billed on inference time, 0.75 Wh per minute — about 45 W — using the carbon intensity of your own grid. A laptop is far less efficient per token than a data-centre accelerator serving dozens of requests in parallel; on the other hand it may run on cleaner power, and there is no network trip. Both totals are shown side by side, with no winner declared.
Does CarbonWatch read my conversations?
No. No content is read, no connection is decrypted, no certificate is installed. The application observes the volume of bytes per connection and the remote address, which it compares with the addresses of known services — never the hostname, never the payload. It requires no administrator rights, no network extension, no account.
Does my data go anywhere?
Nothing leaves the machine until sharing to the global total has been turned on, and it is off by default. Once on, what is sent is, per hour and per service: estimated energy, CO₂e, estimated tokens, service type, electricity grid code and application version. Never sent: IP address, machine name, process names, visited addresses, content. The installation identifier is a random number, and the application can erase every trace of it.
Why does Gemini not appear among the detected services?
Because Google serves its AI from the same addresses as Drive, Gmail and Cloud Storage: detecting them would amount to billing a photo backup as inference. The entry was removed after measurement. The global total therefore undercounts, by an amount nobody can quantify — which is stated on the page about absent services.
Why does this figure differ from the provider's own?
Because they do not measure the same thing. CarbonWatch counts operational emissions only: the electricity of inference. A full life-cycle analysis, such as the one published by Mistral with Carbone 4 and the French ADEME, adds server manufacturing and amortised training — typically 20 to 40% more. Two figures are comparable only if they share the same scope.
How much does a generated image cost?
Image, audio and video generation is not counted in tokens: what arrives is the media itself. CarbonWatch bills it per megabyte received, 2 Wh per megabyte. A 2 MB image therefore costs about 4 Wh, or 1.52 gCO₂e on an American service. No rate cap applies: the media is the payload.
Is this a measurement?
No, and it is written all over this site: it is an estimator, not a meter. The real energy of an inference is known only to the provider. CarbonWatch starts from the volume of bytes received, derives a number of tokens, applies a rate per service type and a carbon intensity per region. Each of those three steps is an order of magnitude, and the ratio between bytes and tokens is the most uncertain of them.
Does it work on Windows and Linux?
On Linux, yes, just as on macOS: the volume exchanged is read per connection, with no special rights. On Windows, the system exposes that volume to no application without administrator rights; the estimate there falls back on established connection time, which makes an idle open tab weigh. Figures are upper bounds, the application says so, and the global total counts them separately.
What does CarbonWatch cost, and what does it do with my money or my data?
The application is free, with no account, no advertising and no telemetry. It resells nothing because it collects nothing: by default, no data leaves the machine. The only possible upload is sharing to the global total — voluntary, anonymous and revocable at any time.