A certified translation is a translation which is accompanied by a declaration by a sworn translator attesting to its accuracy and completeness. A certified translation is sometimes referred to as an ‘official' translation or 'sworn' translation. A certified translation can only be produced by a sworn translator.
A sworn translator attaches a declaration to the translation with an official stamp and his or her signature. The declaration attests that the translation of the original document is correct, faithful and complete. The translation and declaration must be attached to the original document or a certified copy of the original document.
A certified translation can also be ‘legalized’ by a District Court in the Netherlands. This is confirmation that the signature is indeed that of a sworn translator. In this case, mine.