CarbonInk

CarbonInk is a free, open-source desktop application for building greenhouse-gas inventories and preparing disclosures. It is best suited to organizations that need local control over Scope 1, 2, and 3 data rather than a browser-based collaboration hub. Its strongest case is a no-subscription workflow with traceable calculations; the main compromises are desktop-only access and bringing your own LLM API key for document extraction.

Overview

CarbonInk keeps the accounting workflow on a macOS or Windows computer and runs fully offline. User data stays on the device, a meaningful advantage for organizations with strict data-residency or connectivity requirements. The same design rules out browser access and makes it less suitable when several people need a shared, always-online workspace.

The MIT License permits use and modification without a commercial subscription. Installation comes from the macOS and Windows releases, and no activation key is required. AI-assisted intake is optional, but using it requires an LLM API key supplied by the user rather than a bundled service.

Key features

Scope 1–3 inventory with traceability

The inventory records emission sources, activity data, and pinned emission factors across all three GHG scopes. Pinned factors preserve the basis used for calculations, while audit-grade calculation snapshots provide a point-in-time record for review. That combination is valuable when figures must be explained or revisited; users seeking only a quick, lightweight estimate may find the accounting structure more than they need.

AI document extraction

CarbonInk can extract activity data from utility bills, fuel receipts, freight, travel, and purchase documents. This can reduce manual transcription across varied records, but the bring-your-own-key model adds setup and an external API dependency. It is therefore a fit for organizations comfortable managing their own LLM access, not for buyers expecting an included AI allowance.

Disclosures, suppliers, and reports

Inventory data can populate customer or rating-agency disclosure forms, and the app can collect supplier data for Scope 3 Category 1. A one-click ISO 14064-1 inventory report in PDF gives users a defined reporting output instead of leaving them to assemble a document manually. The built-in MCP server also exposes inventory data to Claude, Cursor, and Pi, extending the data into those tools while preserving CarbonInk as the inventory source.

Pricing

CarbonInk has one plan: Free at free. It includes no account, no cloud service, and no subscription, with Scope 1–3 coverage, automated data collection, and supplier engagement. There is no free trial because the product is already free. The absence of accounts and cloud hosting suits individuals or organizations that want a self-contained installation, while teams needing centralized administration or shared browser access should look elsewhere.

Platforms

Desktop builds are provided for macOS and Windows. CarbonInk does not offer a web platform or mobile application, so access depends on having one of those supported computers.

Who it's for

Choose CarbonInk if you need a no-cost Scope 1–3 inventory, supplier Category 1 collection, disclosure preparation, and ISO 14064-1 PDF reporting while keeping records offline. Its pinned factors and calculation snapshots are particularly relevant where traceability matters. It is a weaker choice for distributed teams that require browser collaboration, or for users who do not want to obtain and manage an LLM API key for AI extraction.

Pros and cons

• Pros: Fully offline operation keeps user data on the device.
• Pros: Scope 1–3 tracking includes pinned factors and audit-grade calculation snapshots.
• Pros: Disclosure forms, supplier Scope 3 Category 1 collection, and one-click ISO 14064-1 PDF reporting cover downstream workflow needs.
• Pros: MIT licensing, no account, no cloud, and no subscription remove financial and access barriers.
• Cons: macOS and Windows are the only supported platforms, with no browser workspace.
• Cons: AI extraction requires the user's own LLM API key rather than an included service.

Alternatives

For a broader directory of options, see Carbon Accounting Software.

• Carbonfact is the better choice when you need API and web access, with a free supplier exchange and paid product-LCA capabilities.
• CarbonTool suits organizations wanting a web/API service with a 30-day full-access starter period and paid Core plan.
• EcoReko fits users who prefer a web app with a forever-free single-user, single-site tier and paid expansion.
• Greenio is preferable for web/API deployment with unlimited data entry, four free PDF reports per year, and AI recommendations on its free tier.
• Hedgehog Carbon Platform offers a web-based free tier limited to five emission sources, one user, and one entity.
• Persefoni provides a free self-service web/API plan for one user with unlimited assets and historical reporting years.
• Vaayu is an alternative web/API platform with scope depending on the selected plan and paid pricing available on request.
• 50X Impact is a web-based alternative.

Verdict

CarbonInk is a strong recommendation for organizations that want free, offline Scope 1–3 accounting with supplier collection, disclosures, traceable calculations, and PDF reporting. Look elsewhere if browser collaboration, broader platform support, or an included AI service is more important than local control and zero subscription cost.