Star Life Expectancy Calculator
See how long stars live—from short-lived giants to trillion-year red dwarfs.
Big, bright stars burn out in millions of years. Small red dwarfs can shine for trillions of years—longer than the universe has existed! Enter a star's mass to see how long it will live, how hot and big it is, and how it will end.
Choose your star mass
Enter mass in solar masses (1 = our Sun). Minimum ~0.08; above ~50 the formula is less accurate. Lifetime, temperature, and radius are main-sequence values (hydrogen core burning).
Time spent burning hydrogen in the core
(5,505 °C) effective
(~696 thousand km)
Earth-sized remnant; slowly cools over billions of years.
Stable main-sequence star. Our Sun is in this group—roughly middle-aged.
Why does mass matter?
Bigger stars are much brighter, so they use their fuel faster. They have more fuel (more mass), but not enough to make up for how fast they burn. So heavy stars live shorter lives. The Sun will shine for about 10 billion years. A tiny red dwarf can shine for over 10 trillion years!
Bigger stars are also hotter and larger. But they burn so fast that their lives are still shorter than small, cool stars.
The Paradox of Stellar Lifetimes
Here's a funny thing about stars: the biggest, brightest ones die first. Tiny, dim stars can keep shining longer than the universe has existed! A huge blue star with 50 times the Sun's mass burns out in just a few million years. A small red dwarf can shine for over 10 trillion years.
This calculator uses a star's mass to work out how long it will live and how it will end (white dwarf, neutron star, or black hole). The Sun is about 4.6 billion years old—roughly halfway through its life.
Why Bigger Stars Don't Live Longer
Bigger stars are much brighter. They burn their fuel (hydrogen) much faster. A star twice the Sun's mass is about 11 times brighter—but it only has twice the fuel. So it runs out in about one-fifth of the time. That's why star lifetimes range from millions of years to trillions.
Types of Stars by Mass
Red Dwarfs (0.08 – 0.5 × Sun's mass)
Small, cool stars that burn fuel very slowly. A red dwarf with 0.1 times the Sun's mass can shine for about 10 trillion years. They use almost all of their hydrogen. When they finally run out, they fade into white dwarfs—but the universe isn't old enough for any to have done that yet!
Sun-like Stars (0.5 – 2 × Sun's mass)
Our Sun will shine for about 10 billion years. It's already 4.6 billion years old. Later it will swell into a red giant, then shed its outer layers and leave a white dwarf. A star twice the Sun's mass lives only about 1.5 billion years—too short for life like on Earth to develop.
Massive Stars (2 – 8 × Sun's mass)
These stars live fast and die young. A star with 5 times the Sun's mass lives about 100 million years—enough time for dinosaurs to come and go! They end up as white dwarfs after a lot of changes in their later life.
Very Massive Stars (8+ × Sun's mass)
The biggest stars explode as supernovae. Their cores collapse in a flash and become neutron stars or black holes. A star with 20 times the Sun's mass lives only about 8 million years.
How Stars End Their Lives
A star's mass decides both how long it lives and how it dies.
- White Dwarfs (under about 8 × Sun's mass): The star blows off its outer layers and leaves a small, dense ball (about Earth's size). It slowly cools over billions of years. None have cooled completely yet—the universe is too young.
- Neutron Stars (about 8–25 × Sun's mass): The star explodes in a supernova. The core squashes into a neutron star—as heavy as the Sun but only as big as a city. Some spin fast and beam light like a lighthouse (we call those pulsars).
- Black Holes (above about 25 × Sun's mass): The heaviest stars collapse so much that they form a black hole.
Stars and the Chance for Life
Life on Earth took about 4 billion years to develop. A star has to live that long (and stay stable) for something like us to have a chance. Very big stars don't live long enough. Small red dwarfs live long enough, but they often have fierce flares and their habitable zone is so close that a planet might get "tidally locked" (one side always facing the star). Orange "K-type" stars (between about 0.5 and 0.8 times the Sun's mass) are sometimes called Goldilocks stars—they live 15–30 billion years and are calmer than red dwarfs, so they might be good places to look for life.
Stars Through Cosmic Time
- First stars: The earliest stars were huge and had no heavy elements. They lived only millions of years, then exploded and spread those elements into space. None of them are still around.
- Today: New stars are still forming, but more slowly. Most new stars are red dwarfs—the most common kind.
- Far future: In about 100 trillion years, galaxies will run out of gas to make new stars. Only red dwarfs will be left, slowly fading until the universe goes dark.
Frequently Asked Questions
- Why do big stars live shorter lives?
- Big stars have stronger gravity, so their cores are hotter and they burn fuel much faster. A star twice the Sun's mass burns about 11 times faster but only has twice the fuel. So it runs out in about one-fifth of the time.
- How much longer will the Sun live?
- The Sun will keep shining as it does now for another 5–6 billion years. Then it will swell into a red giant for about a billion years, then shrink to a white dwarf. Earth might be swallowed when the Sun becomes a red giant, or at least get too hot for life.
- Could we make a star last longer?
- In theory, a very advanced civilization could try to "stir" a star and bring more hydrogen to its core. That's still science fiction—but not impossible according to physics.
- What's the longest a star can live?
- The smallest true stars (about 0.08 times the Sun's mass) can shine for over 10 trillion years. Anything smaller doesn't fuse hydrogen properly—we call those brown dwarfs, or "failed stars."