The Catechism in Questions & Answers

230. What is the distinction between sin and guilt?

Sin is absolute. It can therefore not be relativised. It separates from God.
By contrast we may assume that God, in His righteousness and mercy, assesses the degree of guilt an individual incurs with Him through sin differently in each case.

Explanation concerning the extent of guilt incurred: A distinction must be made in assessing the amount of guilt associated with a sin, for example, if someone has stolen out of hunger or to satisfy a craving for some luxury. In both cases a sin has been committed, namely a violation of the Seventh Commandment. However, the degree of guilt a person incurs through this sin can be different. In His omniscience, God will always be fair in judging the degree to which a person has incurred guilt through this sin. Certain influences and situations to which people are exposed, for example, societal structures, situations of need, and pathological dispositions, will also play a role.