So for a total capacity of 145.5 tonnes, you could use 129.5 from departure to destination. Assume an average burn of 7.5 tonnes per hour and an average groundspeed of 480 kts gives a flight time of 17hrs 15mins and a range of 8,288 nms.
Quoting my own reply as I see that I didn’t really answer the OP’s question: “How much of the range of an airplane is used for a flight?”
If the total fuel capacity is 145.5 tonnes, then using the same assumptions, the time from take-off to flame-out would be
145/7.5 = 19hrs and 20mins.
The distance travelled would be 9,280 nms.
Both of these values show that in my previous example, the aircraft used 89% of its ultimate range and endurance.