What’s the distinction? A plenary indulgence removes all temporal punishment due to sin. It is a complete cleansing, as though the disorder caused by sin were fully healed. This means that if a person fulfills the necessary conditions for a plenary indulgence, they can be completely freed from the consequences of their sins, assuming they are in a state of grace and have the intention to receive the indulgence. The conditions typically include sacramental confession, Eucharistic communion, and prayer for the intentions of the Pope, along with performing the specific work to which the indulgence is attached (Catechism, 1471)

A partial indulgence removes part of the temporal punishment. It is a real but incomplete purification, lessening the burden but not entirely eliminating it. The degree of temporal punishment removed is not specified and can vary based on the individual’s disposition and the nature of the act performed. The Church encourages the faithful to seek partial indulgences through various prayers and acts of charity, as these can contribute to one’s spiritual growth and sanctification (Catechism, 1472).

Let’s be clear: an indulgence is not a permission to commit sin.  It is not a permission to indulge in some behavior that would ordinarily be considered sinful.  It is not something that you pay for to get forgiveness. The Catholic Church teaches that indulgences are a means by which the faithful can obtain the remission of the temporal punishment due to sin, the guilt of which has already been forgiven. This teaching is rooted in the Church’s understanding of the interconnectedness of sin, repentance, and the effects of sin on the soul and the community. The Catechism of the Catholic Church provides a thorough explanation of indulgences, particularly in Paragraphs 1471-1479.

An indulgence is a “remission before God of the temporal punishment due to sins whose guilt has already been forgiven [emphasis added], which the faithful Christian who is duly disposed gains under certain prescribed conditions through the action of the Church which, as the minister of redemption, dispenses and applies with authority the treasury of the satisfactions of Christ and the saints.” (CCC 1471)  An important point is that an indulgence does not apply to an eternal punishment (perdition; hell) but only to the temporal punishment for sins that have already been forgiven. And you may have noticed that indulgences are not limited to being applied to the faithful departed, but can be received by the living if disposed under the prescribed conditions.