Why do my numbers in Gravity differ from another report?

Emission figures for the same trips can legitimately differ between two reports. The most common reasons:

• Methodology: methodologies such as DEFRA and TIM use different factors and assumptions, especially for flights. Read How to Pick a GHG or Carbon Calculation Methodology?
• Non-CO2 effects of flights: some reports apply a Radiative Forcing Index (RFI) and others do not. Read What is the Radiative Forcing Index (RFI)?
• CO2 or CO2e: CO2e includes other greenhouse gases, so it is higher than CO2 alone. Read What is the difference between CO2 and CO2e?
• Sources included: Gravity can include rail, hotels, car rental, mobility and expense data, not only what your TMC booked.
• Timing: a trip only appears once its source has delivered it, so a recent period can still be filling up. Read How often is the data in Gravity updated?
• Period and changes: reports may count trips by booking date or by travel date, and treat cancellations and changes differently.

If a difference still does not add up, submit a request with the period and both figures, and we will go through it with you.