Penalties for criminal offences are typically based on four key principles: deterrence, retribution, prevention and rehabilitation.

Deterrence prevents a crime from happening again (or reduces the chance of such occurrence) by instilling fear of the consequences; retribution is based on the principle that the punishment should reflect the degree of harm the offender caused and the extent of culpability; prevention is the idea of putting an offender behind bars so he or she can't harm other victims; and rehabilitation gives an offender a chance at turning over a new leaf.