The Sun is not the big one
How Big Do Stars Get?
Our Sun is enormous compared with Earth and thoroughly ordinary compared with other stars.
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Step 1 of 4
The Sun already breaks your sense of scale.
You could line 109 Earths across the face of the Sun. That is the comparison most people know, and it makes the Sun sound like the extreme case. It is not.
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Step 2 of 4
Some stars are smaller than our planet.
When a star like the Sun finishes, it collapses into a white dwarf — roughly the size of Earth, but still carrying most of the star's material.
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Step 3 of 4
And some would swallow the inner solar system.
The largest red supergiants are so wide that if one replaced the Sun, Mercury, Venus, Earth and Mars would all be inside it, with room to spare.
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Step 4 of 4
Big does not mean heavy.
A red supergiant is vast but incredibly thin — spread out until it is closer to a vacuum than to air. A neutron star is city-sized and unimaginably dense. Width and weight are different questions.
A teaspoon of neutron star material would weigh about as much as a mountain.
The short version
Stars run from city-sized to wider than Jupiter's orbit, and our Sun sits unremarkably in the middle of that range.
Try it yourself
Find a scale picture comparing Betelgeuse with the Sun. The Sun usually has to be drawn as a single dot to fit.