I apologize if something like this has been posted before, but I couldn't find it when I was searching today so I figured out a rough formula for ship transport costs. It will not be exact, but it will give you a good idea. I'll put up the formula first and then explain how I got it with 'proofs'.
Formula: (modifier*distance in light years)*ship value=transport cost or (M*LY)*V=TC
The modifier (M) is roughly 0.0000682
So to figure out the modifier I checked the transport costs and value of two ships in the same system. One is valued at 50,260,816 and the TC is 518,393 this will be marked KP. The other is 329,830,709 with a TC of 3,396,334 this will be marked A. Guess the ships. Anyway, to get the modifier I divided the TC by the distance. Use the Galaxy map for the distance. The in game menu listed it at 155, but the Galaxy map had it at 151.08 and using this gave a more accurate result.
So for KP 518,393/151.08=3431.25. This represents credits per light year. For A it was 3,396,334/151.08=22,480.37.
I took that number and divided it by each ship's value.
KP: 3431.25/50,260,816=0.0000682689
A: 22,480.37/329,830,709=0.0000681573
Using their respective modifiers I plugged in the formula.
KP: (0.0000682689*151.08)*50,260,816=518,393.25
A: (0.0000681573*151.08)*329,830,709=3,396,334.30
The problem here is you need to know the transport costs to figure out the most accurate modifier. There must be some other variable I'm unaware of or not factoring. Or the numbers I'm using aren't exact and hidden somewhere in the game files. However, I settled on 0.0000682 being serviceable. Using that modifier I got the following results.
KP=517,870 vs 518,393
A=3,398,462 vs 3,396,334
Obviously the difference will be more dramatic with higher value ships and longer distances, but it gives you a pretty small ball park to work with. As I get further from the bubble I'll try and fine-tune the modifier.
Oh, I tested the formula on a third ship:
(0.0000682*151.08)*6,595,618=67,959
The transport cost for that ship is 68,896.
Formula: (modifier*distance in light years)*ship value=transport cost or (M*LY)*V=TC
The modifier (M) is roughly 0.0000682
So to figure out the modifier I checked the transport costs and value of two ships in the same system. One is valued at 50,260,816 and the TC is 518,393 this will be marked KP. The other is 329,830,709 with a TC of 3,396,334 this will be marked A. Guess the ships. Anyway, to get the modifier I divided the TC by the distance. Use the Galaxy map for the distance. The in game menu listed it at 155, but the Galaxy map had it at 151.08 and using this gave a more accurate result.
So for KP 518,393/151.08=3431.25. This represents credits per light year. For A it was 3,396,334/151.08=22,480.37.
I took that number and divided it by each ship's value.
KP: 3431.25/50,260,816=0.0000682689
A: 22,480.37/329,830,709=0.0000681573
Using their respective modifiers I plugged in the formula.
KP: (0.0000682689*151.08)*50,260,816=518,393.25
A: (0.0000681573*151.08)*329,830,709=3,396,334.30
The problem here is you need to know the transport costs to figure out the most accurate modifier. There must be some other variable I'm unaware of or not factoring. Or the numbers I'm using aren't exact and hidden somewhere in the game files. However, I settled on 0.0000682 being serviceable. Using that modifier I got the following results.
KP=517,870 vs 518,393
A=3,398,462 vs 3,396,334
Obviously the difference will be more dramatic with higher value ships and longer distances, but it gives you a pretty small ball park to work with. As I get further from the bubble I'll try and fine-tune the modifier.
Oh, I tested the formula on a third ship:
(0.0000682*151.08)*6,595,618=67,959
The transport cost for that ship is 68,896.