Nunc pro tunc is a Latin expression that translates to “now for then”—meaning to do something now, and for it to have retroactive effect, as if it had been done at a previous time. In the legal context, a judgment nunc pro tunc is a new or changed judgment signed by the court that has retroactive effect to the date the corrected judgment was signed.

The purpose of a judgment nunc pro tunc is to correct a clerical error in the judgment after the court’s authority to change the judgment (its plenary power) has expired. Even a significant change to the original judgment may be accomplished through a judgment nunc pro tunc if it merely corrects a clerical error.

Thus, a judgment nunc pro tunc can generally only be used to correct a clerical error the court made when writing or recording (entering) the judgment the court made (rendered)—and not a judicial error (a substantive error in judicial reasoning) in the judgment. In other words, if the signed judgment inaccurately reflects the true decision of the court, then the error is clerical and may be corrected by judgment nunc pro tunc.

In Pennsylvania, the concept of 'nunc pro tunc' is used to correct clerical errors in court judgments or orders after the time to officially modify those judgments has passed. This legal mechanism allows for the retroactive correction of mistakes made in the documentation of a court's decision, ensuring that the written record accurately reflects the court's true intention at the time the decision was made. It is important to note that nunc pro tunc cannot be used to rectify judicial errors, which are substantive mistakes in the court's reasoning or decision-making process. Instead, it is limited to clerical errors, such as typographical mistakes or omissions in the judgment or order. The use of nunc pro tunc is governed by Pennsylvania procedural rules and case law, and requests for such corrections are typically made through a motion filed with the court that issued the original judgment or order.