How long has the Sun taken to use up half of its hydrogen fuel?

The Sun is approximately 4.6 billion years old and has already used up about half of the hydrogen in its core through nuclear fusion. It is currently in the main sequence phase of its life cycle, where it fuses hydrogen into helium to produce energy. Scientists estimate that the Sun will remain in this stable phase for another 5 billion years before transitioning into a red giant and eventually becoming a white dwarf. This long lifespan is due to its relatively moderate size and efficient energy conversion process.