There is often a confusion surrounding a sworn translation versus a certified translation. 

Google offers the following definition:

sworn translation
A sworn translation is a translation officially signed and stamped by a sworn translator and accompanied by the translator’s statement testifying to the truthfulness of the translation.

To clarify, sworn translators produce sworn translations. Informally, the translations may be called certified translations or official translations, but the correct terminology is a sworn translation.

A sworn translator is a linguist appointed by the High Court (in some countries the Ministry of Justice et cetera) to provide certified translations of official documents. They essentially have the power to translate and notarize official documents. This ensures that the document has been translated correctly and is as true to the original as possible. Official documents usually require the translation into the official languages of the relevant jurisdiction. The requirements differ from country to country.

Purely having a document translated and someone else notarize it is not the same.

Linguists are required to register themselves as ‘sworn translators’ so that they can do the translating work. 

Examples of documentation that require a sworn translation include:

•    Medical Reports
•    Contracts
•    Educational Certificates
•    Divorce Orders
•    Marriage Certificates
•    Birth Certificates
•    Death Certificates
•    Wills
•    Forensic Reports
•    Company Articles of Association
•    Patents
•    Affidavits
•    Constitutions

Once the translation is complete, the document still needs to be verified by officials. The translator will be present the translation to officials, who then check that the translation is true to the original. Once they are happy, officials will stamp the document to declare that the translator’s declaration is indeed true and the document approved for use.