Bestimmtheitsgebot

Bestimmtheitsgebot, or the determinacy principle, is a fundamental rule in German private law, especially contract law, requiring the essential terms of a contract to be definite or determinable at the time of formation. The doctrine serves to ensure legal certainty by guaranteeing that the rights and obligations created by an agreement can be identified and enforced. It is closely linked to the concept of essentialia negotii—the essential elements of a contract.

In practice, the Bestimmtheitsgebot means that key terms such as the subject matter and price, the time for performance, and the quantity must be fixed or capable of determination by reference to objective criteria. Determination can be achieved through a stated method (for example, a price index, a price list, or a formula agreed by the parties) or by reference to external standards that are ascertainable.

If essential terms cannot be determined or determined by a valid mechanism within the contract, the agreement may be regarded as lacking determinacy, potentially rendering it ineffective. However, German courts recognize some flexibility: terms may be left to future determination if the contract provides a clear, objective mechanism to achieve determinacy.

The principle influences contract drafting, standard form covenants, and the interpretation of open-ended agreements under German civil law. It also interacts with related concepts such as offer and acceptance, and it is used to assess the validity and enforceability of contracts in practice. While rooted in German jurisprudence, the underlying idea—ensuring determinacy of essential terms—appears in various forms in other civil-law systems.