Originally posted by DeadpoolXXXNamek's size was never directly referenced in canon.
how large is namek though? because unless it's at least 7 times bigger than earth, then it's not a light speed feat.
The only evidence(if you can even call it that) we ever got was King Cold stating that Earth was "such a small planet":
https://ibb.co/GH6PwX5
And Dodoria stating that Namek "isn't such a big planet":
https://ibb.co/nDD8Zn4
Some people have interpreted that as: "not too big" (Namek) > "really small" (Earth)... Which could very well be true, but it still gives us nothing definitive regarding Namek's actual size.
Aside from that, the only 'calcs' you'll see out there are entirely fanmade headcanon. ie. some people will use scans like these to "prove"(via pixel counting, lol) that Namek is actually star-sized or w/e... But that is obviously a huge asspull, and holds no real validity.
You'll also see people argue that since 1st form Freeza destroyed planet Vegeta with no discernible effort, Namek must have been vastly larger because it took a charged attack from 4th form Freeza to destroy its core(which eventually destroyed the planet itself.) However, the actual reason why Freeza didn't instantly vape Namek was provided in the story:
https://ibb.co/vX5zVT8
Freeza held back against Namek because he was worried about getting caught in the subsequent explosion(even though he obviously would have survived)... But he didn't have to worry about that when he destroyed Vegeta, because he was already outside the blast radius. This proves nothing.
Another thing you might see people argue is that Namek must have been waaaay bigger than Earth, because it took some of the Z Fighters several hours to fly from one location to the other:
https://ibb.co/WVRQg4M
But it's worth pointing out that they were suppressing their ki(and therefore overall power) most of the time, as to avoid being detected by scouters. This also proves nothing.
At the end of the day, I feel like Earth is typically *the* measuring stick when it comes to the comparative sizes of fictional planets... So unless an 'alien' world is explicitly stated to be larger(or smaller) than Earth, we can generally assume they are intended to be about the same size. /shrug