This is way more useful to calculate other people’s private jet carbon footprints.

Or at least in my case it is.

once I get my jet I will use this

no way to enter cruise speed or altitude. i guess i could just multiply the fuel burned by some number and get better results. but i don't even know how much fuel i buy, it's so cheap.

Useless as is. Needs to be combined with something like https://www.greatcirclemap.com

Also winds/jet stream at actual flight level at the time flown, and finally the price of Jet-A(1)/B at the involved FBOs.

Or just use something made by Jeppesen, Universal Weather and Aviation, Air Routing International, ForeFlight, ...

Or use the stuff built into the flight deck of any contemporary Jet not belonging into a museeum :)

Or let the pilots handle that, which come with the Jet, anyways, when you charter one.

Delegate!