A sworn translation is a translation produced by a sworn translator and certified as legally valid by them. Authorities accept it as an official document; an ordinary translation is not accepted.
A sworn translation carries the translator’s signature and stamp, together with their number from the national register. It includes a statement in which the translator confirms the translation is complete and faithful. The translation is attached to a copy of the source document, so it stays clear which paper was translated.
Whenever an authority requires an official document in another language. Think of a municipality registering a foreign birth certificate, a court, a notary during a purchase or an inheritance, an embassy handling a visa application, or an employer or educational institution assessing a diploma. If the receiving party asks for a "sworn", "certified" or "assermentée" translation, this is what they mean.
In substance, an ordinary translation can be just as good. The difference is legal: only with a sworn translation does a translator vouch for its accuracy under oath, and only that one is accepted as an official document. An ordinary translation is refused in such a procedure, however good it may be.
With us the price depends on the language combination, not on the type of document. A standard document from Dutch into French, German or English costs €70 excluding VAT; rarer languages cost more. We deliver within five working days as standard, two to three days with rush delivery and 24 hours with express.