Autonomous duties
Customs duties unilaterally set by the EU in its Common Customs Tariff, as opposed to negotiated conventional duties.
Autonomous duties are customs duty rates that the European Union sets unilaterally in its Common Customs Tariff (CCT), independently of any international commitment. They represent the maximum level of tariff protection the EU can apply.
In parallel, conventional duties are rates resulting from negotiations within the WTO (World Trade Organization), particularly commitments made under the GATT. These conventional duties constitute a ceiling that the EU has committed not to exceed ("bound" duties).
In practice, the actually applied duty is the lower of the autonomous and conventional rates. For many tariff lines, both rates are identical. When the autonomous duty is lower than the conventional duty, the EU has unilaterally chosen to reduce its protection, often for industrial supply reasons.
Autonomous duties are periodically revised by the Council and Commission. The TARIC database displays both columns (autonomous and conventional) as well as the actually applicable rate, taking into account any preferences, suspensions, or quotas.