The Tyndall Travel Tracker has a fairly simple carbon calculator (https://travel.tyndall.ac.uk/); with respect to offsetting there is an ongoing debate currently about how best to achieve this. It is thought that offsetting carbon alone is quite a grey area at present (e.g., trees planted today will offset over 25 years but the damage is done in the now, also many offsetting schemes are...scammy) - we are currently discussing strategies to offset with more than carbon, including development activities as well as biodiversity protection; the problems can be quite linked.

My personal hope is to liaise with some of the best researchers in the world regarding offsetting and have an approved offsetting scheme, which can be applied anywhere, that updates based on the current best understanding; we would then bring this capability into a newly built travel tracker (it's closer to a prototype atm).

Please let me know if this is something you'd find interesting.