It is much too small.
Example: "Unfortunately, the shirt is much too small. I think it should be at least one size bigger."
Das ist viel zu klein. 
Den är alldeles för liten 
Den er alt for lille 
Den er altfor liten 
Se on aivan liian pieni 
See on liiga väike 
Gerokai per maža 
Tas ir daudz par mazu 
Það er allt of lítið