Add to Chrome
Add to EdgeUses ChatGPT, Gemini or Claude every day and has no idea what a session adds up to.
What they get: A running token estimate beside the page while they chat, kept on their machine in guest mode.
CrbonFree for Chrome and Edgev1.0.1Measure what you use
The token counter that runs inside your AI chats.
One click adds it to Chrome or Edge, and it estimates the tokens in each ChatGPT, Gemini and Claude session while you chat. Guest mode keeps everything on your machine, and signing in keeps the history in your dashboard.
estimate on methodology v1.2
250,000
- Tokens
- 250K
- Active energy
- 24.3 Wh
- CO₂e
Band of 28 percent: 40 g to 71 g
- Layer 1, active energy12 g
- Layer 2, facility operation48 g
- Layer 3, full lifecycle55 g
This is the aggregate medium-tier estimate, with the methodology’s 75 to 25 split of input to output tokens. The extension estimates each session on its own, so its per-session number will differ.
3
chat products covered: ChatGPT, Gemini and the Claude apps
1
click to add from either store
3
layers in the carbon methodology, version 1.2
28
percent uncertainty band on every estimate, stated
What is the Browser extension?
The CrbonFree browser extension is a token counter for Chrome and Edge that covers your AI chat sessions across ChatGPT, Gemini and the Claude apps, including Claude Code. Added from either store, it shows the estimate while you chat. Guest mode keeps everything on your machine. Signing in sends the usage to your CrbonFree dashboard, where the backend converts tokens to CO2e with methodology v1.2.
Last checked against the product on 5 September 2026. Carbon figures follow methodology v1.2.
At a glance
- Store
- Chrome Web Store and Microsoft Edge Add-ons
- Version
- 1.0.1
- Requires
- Google Chrome or Microsoft Edge
- Covers
- ChatGPT, Gemini and the Claude apps, including Claude Code
- Counts
- Token estimates per session, exact where the site provides one
- Modes
- Guest, on your machine, or signed in
- Data direction
- Nothing leaves in guest mode, usage uploads when signed in
- Price
- Free
An estimate for every chat session, on the sites you already use
Open ChatGPT, Gemini or one of the Claude apps and the extension estimates the tokens in the session while you chat. There is nothing to configure and no key to paste, and the store listing says it uses an exact count where the site makes one available.
Guest mode on your machine, or sign in to keep the history
The store listing states that guest mode keeps everything on your machine and sends nothing to CrbonFree. Sign in and your usage is kept as history you can review conversation by conversation, grouped by account and organisation. The listing also states that private chat messages are not sent to or stored by CrbonFree.
The same methodology as the rest of the product
When a session reaches your dashboard, the backend converts its tokens to CO2e with methodology v1.2: active energy first, then facility operation, then the full lifecycle. Every figure carries the same 28% uncertainty band as a provider connection or a coding agent session, so chat usage sits in the same report as everything else.
One click to add, nothing else to set up
The extension installs from the Chrome Web Store or Microsoft Edge Add-ons in one click and runs in Chrome or Edge. There is no package to install, no API key to create and no scheduler to register, and guest mode works without an account at all.
How the Browser extension moves your data
- 1
You chat
You open ChatGPT, Gemini or one of the Claude apps and use it the way you already do. The extension runs in Chrome beside the page.
- 2
The extension estimates the session
It estimates the tokens in the session as it grows and shows the running figure while you chat. Where the site provides an exact count, the listing says it uses that instead.
- 3
The estimate runs through the methodology
Tokens become energy and then CO2e with methodology v1.2, and every figure carries its 28% uncertainty band.
- 4
Sign in to keep the history
In guest mode the numbers stay on your machine. Signed in, the usage lands in your dashboard next to your provider connections and coding agents, and private chat messages are not sent.
How to get started
- 1
Add it to Chrome or Edge
Open the listing on the Chrome Web Store or Microsoft Edge Add-ons and add the extension. It needs one of the two browsers and nothing else, and it is free.
- 2
Open a chat site and watch the estimate
Go to ChatGPT, Gemini or one of the Claude apps and start a conversation. The extension shows its estimate for the session while you chat, with nothing to configure.
- 3
Sign in to keep the history
Guest mode keeps everything on your machine and keeps nothing once the session is gone. Sign in with your CrbonFree account and each session is kept, grouped by account and organisation, and reported in your dashboard as CO2e.
It lands in your dashboard
Signed-in sessions arrive in the dashboard beside your provider connections and coding agents, converted with methodology v1.2 and reported with the same uncertainty band. The sample account shows what that report looks like without a login.
Open the sample accountWhat it does not do
It estimates. The extension produces a token estimate per chat session rather than the metered count a provider connection returns, and the listing says an exact count is used only where the site makes one available. Chrome and Edge are the browsers with a store listing, and coverage is ChatGPT, Gemini and the Claude apps, with nothing else today. The guest mode and privacy statements on this page come from the store listing and have not been checked against the source.
Who reaches for the Browser extension
Wants the team’s chat usage in the same place as its API and coding agent usage without asking anyone to change tools.
What they get: Everyone adds the extension and signs in, and the sessions land in the dashboard grouped by account and organisation.
Needs the chat tools staff use in the same report as the production workloads, with a stated method behind the figure.
What they get: Signed-in sessions are converted with methodology v1.2 and carry the same uncertainty band as everything else, reported as estimates rather than metered counts.
Which CrbonFree surface do I need?
Three of them put usage in: the dashboard through provider connections, the CLI for coding agents and the browser extension for chat sessions. The other four read the numbers back into your own code. The Browser extension is highlighted.
| Surface | Meters usage | Reads numbers back | Runs | Needs | Language |
|---|---|---|---|---|---|
| Dashboard | In the browser | An account; the sample account opens without one | None | ||
| CLI | status | On your machine | An account; device code for headless machines | Node 20 or newer | |
| Browser extensionthis page | estimates | In Chrome | Optional, per the store listing | None | |
| TypeScript SDK | Node 18 or newer | An API key | TypeScript or JavaScript | ||
| Python SDK | Python 3.8 or newer | An API key | Python | ||
| MCP server | Beside your MCP client | An API key from login | Any MCP client | ||
| REST API | Over HTTPS | An API key | Any |
Questions
Questions about the Browser extension.
Short answers. The package page and the API reference have the long ones.
Add to ChromeFor chats in the browser, add the extension and open ChatGPT, Gemini or a Claude app: it estimates the tokens in the session as you go, and signing in keeps the history per conversation in your dashboard. For API and coding-agent usage, a provider connection or the CLI gives metered counts rather than estimates.
The store listing states that private chat messages are not sent to or stored by CrbonFree. In guest mode nothing leaves your machine at all. When you sign in, the extension sends usage information so the dashboard can keep the history.
ChatGPT, Gemini and the Claude apps, including Claude Code, as the store listing describes. Nothing else is covered today.
The extension estimates the tokens in a session rather than reading a metered count from the provider, and the listing says it uses an exact count where one is available. Once a session reaches the dashboard, those tokens are converted to CO2e with methodology v1.2 and reported with a 28% uncertainty band, the same way as every other source.
Yes. The extension is free on both stores, and tracking usage and carbon estimates on the free plan costs nothing. Signed receipts, audit packs and trust assets are part of the paid plans.
Google Chrome and Microsoft Edge, through the Chrome Web Store and Microsoft Edge Add-ons. We have not tested other browsers that can load Chrome extensions, so treat those two as the requirement for now.
Goes well with
All productsDashboardEvery provider, project and coding agent in one report. The sample account opens without a login.CLIMeter your local AI coding agents automatically, synced to the dashboard every hour.TypeScript SDKA typed client for your usage, emissions, receipts and audit packs from Node.js or TypeScript.
See your own number instead of ours.
However your team already runs AI, that is how you connect. Paste a read-only provider key, drop in an SDK, add the MCP server, install the CLI or switch on the browser extension, and the first measured tokens reach your dashboard within seconds.
Create your free account
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