About
0xCarbon is an independent, openly licensed dataset on the carbon cost of European travel. It earns affiliate commission on accommodation bookings and nothing else; the emissions figures are computed from published government sources by a pipeline that knows nothing about it.
Why this exists
There are many carbon calculators. Nearly all of them work the same way: you tell them the trip you have already chosen, and they tell you what it cost. That is a receipt, not a decision aid — by the time you use it, the decision is made.
0xCarbon runs the other way. It starts from what people actually want — somewhere warm, in a particular month, within a journey they will tolerate — and shows which places deliver that for the least carbon. The answer is usually shorter and more surprising than expected, and it contains a cliff: a point where one more degree of warmth suddenly costs an order of magnitude more.
How it is funded
By affiliate commission on accommodation, and by nothing else. Every destination page, every monthly frontier, every departure hub and the homepage carries a map of places to stay, provided by Stay22. If you book through it, 0xCarbon earns a commission and you pay no more than you otherwise would. Every one of those maps carries a disclosure; the methodology, data, about and departures-index pages carry no map at all.
There are no adverts and no display advertising. Stay22's script also rewrites outbound travel links on this site into affiliate links; that script and the accommodation map embeds are the only third-party code this site itself loads. Fonts are served from this domain, and there is no tag manager and no advertising pixel.
One thing is added after the fact and should be named: the site is hosted on Cloudflare, and Cloudflare injects its own Web Analytics beacon into every page at the edge. It is not in the source and is not something the site requests, but it does load and it does count visits. It sets no cookie, builds no cross-site profile and is not used for advertising — it measures page loads and how fast they were, and nothing about it reaches Stay22 or affects any figure here.
Why the money cannot reach the numbers
This matters more here than on most sites, because the whole proposition is that the figures are trustworthy — and the figures frequently tell younot to take the expensive trip.
The emissions and climate data are computed by a pipeline that has no knowledge of Stay22 at all — the file that builds every frontier contains no reference to it, to affiliates, or to money, and you can check that in the published source. Carbon comes from UK Government conversion factors applied to distance; temperature, sunshine and rainfall come from ERA5 reanalysis. The frontier is then a Pareto selection over those two numbers alone: a place appears only if nowhere else is both better and lower-carbon. Where two places are within a fraction of a degree of each other, the better-known one is shown — decided by how many languages name it, which is again data rather than a choice made here.
The ranking is finished before anything commercial happens: the accommodation map is generated from the coordinates of whichever destination the data already chose. What a booking pays is set by Stay22 and its partners, is not visible from here, and is not an input to anything. The whole dataset is published under CC BY 4.0 so that anyone can check all of this rather than trust it.
Independence
0xCarbon is not affiliated with, endorsed by, or funded by any airline, rail operator or tour operator. Its only commercial relationship is the affiliate arrangement with Stay22 described above.
Corrections
If a figure looks wrong, it may well be — the methodology page lists the known weaknesses, the largest being that rail journey times are modelled rather than taken from timetables. Corrections are genuinely welcome.
Contact
General enquiries, corrections and data questions: hello@0xcarbon.com.
The 0xcarbon.com domain and this project may be available to the right owner. Enquiries: hello@0xcarbon.com.
Colophon
Built with Astro as a fully static site — no server, no database, no client-side data fetching. Every frontier is computed in advance by a Python pipeline and shipped with the page. Type is Inter. The dataset was generated on 2026-09-03.
Emissions factors: UK Government GHG Conversion Factors 2026 (DESNZ/DEFRA), OGL v3.0. Place data: GeoNames, CC BY 4.0. Climate: Open-Meteo (ERA5), CC BY 4.0.