What has confused is when I display my ships spec in outfitting it reads: JUMP MIN / CURRENT / MAX 26.17 / 29.14 / 31.14LY. Is the MIN fully loaded (my cargo is not to capacity) ? - obviously I get 29.14LY is my current range - but what about the 31.14LY - how does relate to the 35.15LY ?
Those calculations in the outfitting screen refer to your jump range with your ship fully laden (min), your range with your current cargo load (current) and your range with your ship unladen (max). The min and maximum values are calculated assuming you're carrying your maximum fuel load although in practice as your fuel mass changes these numbers would also change.
Where it can get confusing is with your "current" jump range which varies both based on cargo mass as well as your current fuel mass. If your fuel tank is filled to less than maximum then the outfitting screen calculations will accurately calculate the "current" jump range based on your actual fuel load in the same was as with cargo. The min/max numbers will still be calculated assuming you have a full tank of fuel however. Presumably if you were to replace your fuel tank with a smaller tank then the min/max numbers would be re-calculated but I haven't done this myself.
The other way to check your jump ranges is shown in the right ship info screen inside your ship cockpit. This shows your current jump range followed by your maximum jump range in brackets. The difference compared to the outfitting screen is that the "maximum" jump range is shown not based on unladen mass but assuming an empty fuel tank. The "current" jump range will get close to the "maximum" number shown in brackets as you use fuel on jumps but will never quite reach this number.
Generally these issues won't make much difference other than in a few special circumstances. For example, if you plot a trip before refuelling your tank you might find that after refuelling this increases the ship mass enough that you can't make one of the plotted jumps and you will need to re-plot the trip. This can happen with the larger ships where they are sometimes limited more by their fuel limit per jump than by the FSD range itself. I have had this happen in my Anaconda a few times when I plotted a jump course before refuelling, and then when I leave the station and try to jump it tells me that I can't make the jump because it would use more than 8 tons of fuel (which is the limit for a class 6 FSD). The other issue that this can cause even if you can still make the jumps is that some of the longer-range jumps will become much less efficient in terms of fuel consumption if you are operating near the absolute upper limit of your jump range and this can make the jumps less optimal if you're taking on a large enough amount of fuel mass. As a result I've gotten into the habit of refuelling first before plotting any jumps in my Anaconda or Python.
