CarbonInk

CarbonInk is a free, open-source desktop app for greenhouse-gas accounting. It suits teams that want an offline Scope 1–3 inventory, disclosure workflows, and PDF reporting without a cloud account. Its desktop-only reach and reliance on your own LLM API key for AI extraction are the main trade-offs.

Overview

CarbonInk brings emissions tracking, supplier data collection, disclosure forms, and inventory reporting into one offline workflow. Keeping data on the device is a strong fit for organizations that want local control; it also means the app is not a web-based shared workspace.

The MIT License and no-cost plan make it accessible without a subscription commitment. In return, users need a macOS or Windows machine, and anyone seeking AI document extraction must supply their own LLM API key.

Key features

Scope 1–3 inventory and audit trail

The inventory records emission sources, activity data, and pinned emission factors across Scopes 1, 2, and 3. Pinned factors and calculation snapshots support traceability, which matters when figures need to be reviewed or explained later.

Document extraction and supplier data

AI can extract activity data from utility bills, fuel receipts, freight, travel, and purchase documents. Because it uses the user's own LLM API key, this is not a turnkey AI service: users must bring a key and account for that dependency. CarbonInk also supports collecting supplier data for Scope 3 Category 1.

Disclosures, reporting, and connected tools

Users can populate customer or rating-agency disclosure forms from their inventory, then generate a one-click ISO 14064-1 inventory report as a PDF. A built-in MCP server exposes inventory data to Claude, Cursor, and Pi, giving users of those tools a way to work with their inventory without changing the app's offline-first approach.

Pricing

Free: free. There is no account, cloud service, or subscription, and no free-trial countdown or activation key. That makes it a straightforward option for individuals and teams willing to use a desktop workflow; there are no paid tiers described to add seats, cloud collaboration, or other capacity.

The free plan includes the core Scope 1–3 inventory, automated data collection, supplier engagement, disclosure workflows, and PDF reporting. AI extraction still requires the user's own LLM API key, so free access to CarbonInk does not remove that separate requirement.

Platforms

CarbonInk runs on macOS and Windows, with builds obtained from its releases page. It runs fully offline, and user data stays on the device. This is a clear advantage for local data control, but rules out browser-based access and limits use to the supported desktop platforms.

Who it's for

CarbonInk is best for users who need a no-cost, locally stored Scope 1–3 inventory with a traceable calculation record and a PDF reporting path. It is also a sensible fit for organizations that collect supplier Scope 3 Category 1 data or complete customer and rating-agency disclosures.

Look elsewhere if your workflow requires a web app, a platform beyond macOS or Windows, or AI extraction without arranging your own LLM API key. Teams looking for cloud collaboration should not mistake an offline desktop tool for a shared hosted system.

Pros and cons

• Pros: Free, open-source, and usable without an account, cloud service, subscription, or activation key.
• Pros: Scope 1–3 tracking combines pinned emission factors with calculation snapshots, supporting a more auditable inventory.
• Pros: Disclosure workflows, supplier data collection, and ISO 14064-1 PDF reporting cover several steps beyond basic emissions tracking.
• Cons: macOS and Windows are the only supported platforms, so it does not suit browser-first or other-platform workflows.
• Cons: AI extraction depends on the user's own LLM API key rather than being ready to use on its own.
• Cons: Fully offline operation keeps data local but does not provide a cloud workspace for teams.

Alternatives

For a broader comparison, browse Carbon Accounting Software.

• Carbonfact is a better fit for product-focused work: it offers Product LCA and a free supplier environmental-data exchange with free LCA verification and supplier-controlled data visibility.
• CarbonTool is worth considering if you prefer API or web access and want to start with a 30-day full-access trial covering core Scope 1 and 2 measurement.
• EcoReko suits users who want a web-based option with a free forever plan capped at one user and one site, while still tracking Scopes 1, 2, and 3.
• Greenio is a web and API alternative whose free plan includes unlimited data entry, Scope 1–3 tracking, AI recommendations, an activity log, and four PDF reports per year.
• Hedgehog Carbon Platform may suit users who want a web-based free tier with an AI onboarding guide, though its free plan is limited to five emission sources, one user, and one entity.
• Persefoni offers a free self-service Pro plan for a single user with unlimited assets and historical reporting years, making it an alternative for users who prefer API or web access.
• Vaayu is a web and API alternative with a free plan whose scope depends on the selected plan; paid-plan pricing is available on request.
• Carbonstop Ccloud is an enterprise carbon-management alternative offered for web and self-hosted use, with pricing available on request.

Verdict

Choose CarbonInk for free, offline Scope 1–3 accounting with disclosure workflows, supplier data collection, and a traceable PDF reporting path. Its strongest reason to choose it is the combination of local control and broad inventory functionality without a subscription; its strongest reason to look elsewhere is the desktop-only footprint, especially if you need a web workspace or built-in AI access without your own API key.