How We Estimate Your Annual Offset Need

Our calculator gives you a fast, transparent estimate using widely recognized emissions references and simple math. It is designed for speed and consistency (not a formal GHG inventory).

Formula used:

Estimated tons CO₂e/year =
(People × 2.5) + (Gas/Diesel Vehicles × 4.6) + (One-way Flights × 0.3) + (Home sq ft × 0.0015)

What each factor means:

• 4.6 tons per gas/diesel vehicle comes from the U.S. EPA’s estimate for a typical passenger vehicle’s annual CO₂ emissions. (epa.gov)

• Flights are estimated using a simplified per-flight factor, informed by ICAO’s passenger-flight emissions methodology (which varies by route, aircraft, load, and cabin class). (ICAO)

• Home-energy component uses a simplified square-foot proxy; official conversion-factor frameworks (like UK DESNZ/BEIS) show that energy emissions depend on fuel mix and local grid factors, which is why this is an approximation. (UK.GOV)

• Household baseline per person is a practical catch-all so users can estimate quickly before doing a full footprint study.

Important note:
This tool is for quick planning and purchase guidance. For formal reporting and more comprehensive purchase options (e.g., corporate inventories, assurance, or compliance), we recommend using a full boundary-based methodology and activity-data audit and scheduling a call with a member of our corporate purchase team here.