Carbon accounting
done right.
c12 is an offline-first desktop app for rigorous Scope 1, 2, and 3 carbon accounting. Fully compliant with GRI 305 and ISO 14064. Includes a complete UNGC COP questionnaire. Free community edition. No account, no internet, no lock-in.
macOS · Windows · Linux · Data stays on your device
Coverage
All three scopes
Scope 1
Direct emissions from sources your organisation owns or controls: combustion, fugitive refrigerants, company vehicles.
Scope 2
Electricity and purchased energy. Both location-based and market-based methods, with contractual instrument tracking.
Scope 3
All 15 value-chain categories per GHG Protocol: upstream supply chain, business travel, employee commuting, investments.
Compliance
Built to standard
No exceptions, no workarounds. Every calculation follows the standard as written.
GHG Emissions
Disclosures 305-1 through 305-7, fully covered
GHG Inventories
Organisational boundary, uncertainty, audit trail
Ten Principles
28-question questionnaire with auto-populate
Corporate Standard
Scope 3 categories, dual Scope 2 methods
Features
Everything you need to report
Offline-first
All data lives on your device in a local SQLite database. No internet required to run, calculate, or report.
GRI 305 reports
Generate disclosure-ready reports for all seven GRI 305 disclosures: intensity, reductions, ODS, air emissions.
UNGC COP
Complete your annual Communication on Progress. Environmental questions auto-populate from your emissions data.
Immutable audit trail
Every data change is logged and cannot be deleted. Required by ISO 14064-1 §8 for verifiable inventories.
Emission factor library
Built-in DEFRA, EPA, IEA, and GHG Protocol factors across AR4, AR5, and AR6 GWP values.
Multi-entity support
Subsidiaries, facilities, JVs, and branches, each with its own boundary and ownership percentage.
Pricing
Two tiers, one tool
Community is free forever. Enterprise adds cloud sync and teams. Start with a two-week trial.
Community
Free
Forever. No account required.
- ✓ Scope 1, 2, and 3 data entry
- ✓ GRI 305 full disclosure report
- ✓ UNGC COP questionnaire
- ✓ Immutable audit log
- ✓ CSV export
- ✓ Unlimited reporting periods
- ✓ No account required
Enterprise
$20 / seat / month
14-day free trial · no card required.
- ✓ Everything in Community
- ✓ Cloud sync across devices
- ✓ Multi-user access with roles
- ✓ Single sign-on (Okta, Azure AD, Google)
- ✓ Priority support with SLA
- ✓ 14-day free trial · no card required
Get started
Start your first inventory today.
Download the desktop app. No sign-up. Your data stays on your device.
Download c12 free →