What does "Ex Nunc" Mean?

Jessica Ellis
Jessica Ellis

Ex nunc is a Latin term that means “from now” or “from now on.” It is frequently found in legal terminology, where it can be used to describe the jurisdiction of a ruling or contract. It is also used in contrast with ex tunc, another Latin phrase that translates as “from the outset” or “from the beginning.” An ex nunc ruling can affect things only from the moment of its existence onward.

Woman standing behind a stack of books
Woman standing behind a stack of books

Contrasting ex nunc and ex tunc is a little like understanding the difference between a divorce and an annulment. While a divorce means that a marriage is ended from the point of the final decree onward, an annulment stretches back into the past to declare that the union never legally existed. Similarly, an future-altering decision or situation deals with events moving forward, such as the termination of a legal contract. An ex tunc ruling, however, might declare that a contract was invalid from its inception.

There are several instances when this concept is important to legal procedure. Contract law is one such situation, in which clauses may specify actions, agreements, or conditions for the future of the contract, but do not refer to prior agreements. Laws or legal systems that permit amendments are also usually subject to measures that take effect ex nunc.

Knowing when this type of clause or ruling comes into effect can have a profound impact on criminal and civil law proceedings. If in 2002, a nation outlawed square-dancing ex nunc, a person could not be prosecuted or ticketed for square-dancing prior to the law taking effect. On the other hand, if in 2004 the nation added an exemption that allowed high schools to have square-dancing fundraisers ex nunc, fundraisers held before the exemption took effect could potentially be in danger of prosecution.

The institution of Prohibition in America in the early 20th century is an example of ex nunc laws. The 18th amendment of the US Constitution banned the sale and production of alcohol “after one year from the ratification of this article.” This ruling dictated future behavior, making it a perfect example of a law that took effect “from now on.” When the 21st amendment repealed Prohibition, it also took effect ex nunc. Repealing a law through these types of rulings does not mean that the law was illegal, or that those prosecuted under a former law were treated unlawfully. As opposed to the annulment of a law, a repeal merely says that the law is now changed.

Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a wiseGEEK writer.

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Discussion Comments


I have to ask how the term ex post facto plays into the ex nunc? I am guessing that they have similar meanings and may even play hand in hand with each other.

I know that someone in the United States cannot be prosecuted for something committed ex post facto, which means it was committed before the law was in place, and this sounds strikingly similar and almost identical to the term ex nunc.

I am wondering what are the differences, if any of the terms ex nunc and ex post facto and maybe if they are just different terms for the same thing?


@jcraig - I think that this article is simply outlining a relatively common term that is used in the legal system and probably did not specify how common it actually is.

I am also under the same assumption, but I know that there are always exceptions to the law and that there are certain instances in which a law that has been created can be broken in such a way that the person will not be prosecuted.

I do not know if ex nunc also means that there are exceptions to the law or if it is taking a stand that everyone is forgiven and will not be punished and will only do so in the future, no questions asked, or if there are exceptions to this term.


I know that ex nunc seems to be something in the legal system that is supposed to create a precedent that will be observed from here on, but in reality is not every single law that is created on the books like that?

To my knowledge when the law is changed or adding it means the legal laws and codes that form societies have been altered from here on. That one change in the law is supposed to cover instances from here on that otherwise would have been illegal before.

I do not really understand the importance of this term, when it seems to me like every single law out there creates a change with the intention of being etched in stone, from here on, at least until the law is changed or repealed later on.

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