udvostručiti

1. to double
   Firma je prošle godine udvostručila profit. — The company doubled its profit last year.
   Moramo da udvostručimo napore ako želimo da uspemo. — We have to double our efforts if we want to succeed.
2. (udvostručiti se) to double; to increase twofold
   Cene stanova su se udvostručile za pet godina. — Apartment prices doubled in five years.

Without se it takes an object (+ acc.); with se it means to double or increase twofold.