Updates to how we calculate flight emissions from January 2026
You might have noticed that CO2e for flights recorded in 2026 is lower than in previous years. Well, as of 1st January 2026, the calculator was updated to use the most up‑to‑date flight factors from the UK government (BEIS), and these are noticeably different to the previous factors. This is all part of our ongoing commitment to keep your results accurate, robust and trustworthy over time.
Why are they noticeably different?
Previously, the UK government’s carbon factors the calculator used were based on travel patterns from 2021, when planes and trains were carrying far fewer passengers due to COVID‑19. Because there were fewer people sharing the journey, emissions were spread across fewer passengers, making the CO2e per person, per km travelled much higher.
Now that travel has returned to more normal levels, flights are fuller again. That means emissions are shared across more passengers, resulting in lower emissions per person, even though the total emissions from the vehicle itself haven’t changed. The UK government has now updated their carbon factors to reflect this and this latest update ensures these new factors are used to calculate flight emissions.
As an example, a return flight from Heathrow to Cape Town in Business class was 12.6 tCO2e when measured previously. As of now, the calculator will reference this updated factor, which results in 7.9 tCO2e, more than a third less than before.
What does this mean for us?
To keep your reporting as clear and comparable as possible, we’ve applied this update carefully. All travel entries dated from 1 January 2026 onwards* use the updated data, giving you one consistent approach for the whole of the year. Your 2025 data stays exactly as it was, using the factors that applied at the time, so your previous annual footprint remains a stable baseline.
This means that if you’re reviewing 2026 reports and referring back to previous years, you may notice a drop in People Transport emissions (specifically in flights), if your flight activity is broadly the same year to year.
What do we need to do?
Nothing at all, everything has been updated automatically in the calculator so you can carry on logging activity as usual. This news item is purely for your reference and to help you understand why these differences in flight emissions have occurred, and what you might expect to see when comparing 2026 data to previous years.
I have further questions…
No problem, email us and we’ll be happy to help.
*Note that this update was implemented on 19th January, so for flight activity entries created from 1st - 18th January, the calculations have been re-calculated automatically, and the new factor used.
