Interactive Tools
Black Hole Size Comparison
How big are black holes really? Compare the sizes of a stellar black hole, Sagittarius A*, Interstellar's Gargantua and the giant M87*, against the Earth and the Sun.
Last updated 23 May 2026 · How we research
Smallest to largest · logarithmic scale
Bars use a logarithmic scale: each step represents roughly a tenfold change in size, because the real range, from a city-sized black hole to one larger than the solar system, is far too vast to show directly. Tap any bar for detail.
Black holes come in an astonishing range of sizes, from objects a few times the mass of our Sun to monsters billions of times heavier. This comparison shows their event horizons side by side, set against familiar objects like the Earth and the Sun, so you can grasp just how vast the difference is.
From stellar to supermassive
The smallest black holes form when massive stars collapse, and are only a few kilometres across despite weighing more than the Sun. At the other extreme sit the supermassive black holes that lurk at the centres of galaxies, like Sagittarius A* at the heart of our own Milky Way and the colossal M87*, the first black hole ever photographed. Because a black hole's event horizon grows in direct proportion to its mass, these giants are wider than entire solar systems. The understanding of these objects rests on the work Hawking did on black holes throughout his career.