How much extra space is needed for ALTER TABLE MOVE

I have a table allocating more 1T with a very high percentage of waste space (estimated less than 100GB used)

So planned for

alter table TABLE_NAME move;

and index rebuilding

to gain back wasted space

This activity need temporary space and I need to calculate how much.

what's the best way to evaluate how much space I need for moving ?

I suppose it's non necessary 1TB of free space for the activity.

Furthermore, before exeuting move command, does this space need to be allocated in the tablespace or having it free in disk group is enough ?