How much does the TARDIS weigh?

[the Dagman]

The mass a TARDIS can hold is potentially infinite. The mass listed in Castrovalva was the amount of mass that had been put into the TARDIS's interior dimension at that point. But a TARDIS can take on more mass, merely by materializing around an object. The Doctor can have that mass materialize in any room within the TARDIS. And via the control console of the ship, use that mass in any way he should need.

So the answer to how much does the TARDIS weigh actually can fluctuate to a great degree.

 

[Sci]

I think I've seen times when the TARDIS was immovable as well as times when it can easily be moved. I think it depends on whether or not it is "anchored." If the Doctor sets the parking brake or whatever, then the TARDIS can't be moved. Without the anchor, I think the TARDIS weighs what you'd expect a Police Public Call box to weight.

I like the episode "Father's Day" when the TARDIS interior vanished because of a paradox and it was just an empty box on the inside. It implies that the exterior is not particularly special and that it only serves as an interdimensional bridge to the interior. I think that's kind of implied in the last episode of seaon 4 or season 30 when the doctor implied that the exterior was just an ordinary police box in the face of super-advanced Dalek tech.

I didn't get that sense at all. A wooden police box would have been consumed far more quickly by the Crucible's energy core than the TARDIS was. Further, the show has made it clear on numerous times that it's not that the interior is another dimension -- it's just genuinely, honest-to-goodnessly bigger on the inside than it is on the outside.