Addendum vs amendment
An addendum adds new terms to an existing contract; an amendment changes existing terms. Confusion between the two causes invalid clauses and disputes at renewal time.
What is the difference?
An addendum adds content: new provisions, appendices, or scope, without touching the existing text. An amendment modifies existing clauses — for example a new rate or an updated notice period.
Example
- Addendum: a new module is added to a SaaS contract, with its own pricing and SLA. Original terms remain fully in force.
- Amendment: the monthly fee in article 4 is raised from €2,500 to €2,800. Article 4 is literally overwritten.
When it matters
In price indexation, scope expansion, and renewal negotiations, choosing the right form is essential. An "addendum" that actually alters a clause can be ruled invalid because the original article remains in place.
Common pitfalls
- Using an "addendum" to change prices — legally an amendment.
- Missing cross-reference to the original contract number.
- Forgetting to have both documents signed by the same authorized signatories.
How GuardPilot flags this
The Obligation Radar links every addendum and amendment to its parent contract and flags conflicts: an addendum touching an existing clause is queued for legal review.
Related terms: Contract management · Renewal clause · Side-letter