The Sun has several billion years of life left as a star similar to what it is today. Eventually it will swell into a red giant and then end as a white dwarf.
Main sequence lifetime
Astronomers estimate the Sun will spend about 10 to 11 billion years total in its current “main sequence” phase, steadily fusing hydrogen into helium in its core. The Sun is about 4.6 billion years old, so it is roughly halfway through this long stable period.
Time until major changes
Models of stellar evolution indicate the Sun will start to exhaust hydrogen in its core and leave the main sequence in about 5 to 6 billion years. At that point it will swell into a red giant, becoming much larger and more luminous and eventually shedding its outer layers and leaving behind a white dwarf.
Habitability for Earth
Even though the Sun will last billions of years, conditions on Earth will worsen much sooner because the Sun slowly brightens over time. Its luminosity is expected to increase enough over roughly the next 1 billion years to drive ocean evaporation and make Earth uninhabitable at the surface. Long before the Sun’s final red giant phase, Earth will likely be too hot for liquid water, and in later stages the expanding Sun may engulf or severely scorch the inner planets.
