Contract Addendum Template

A free contract addendum template that attaches new terms to an agreement the parties already signed, without changing the language of the original document. Download it in PDF or Word, fill in the bracketed fields, and sign.

Last updated: August 5, 2026

What Is a Contract Addendum?

A contract addendum is a supplemental document added to an existing contract to cover something the original did not address. It is incorporated into the underlying agreement by reference, so the two documents are read as one, but it leaves the original text intact. Typical additions are an extra service, an additional site or property, a new fee schedule, a data protection annex, or a set of rules that did not exist when the contract was signed.

The distinction from an amendment is practical rather than ceremonial. An amendment reaches into the original agreement and rewrites clauses; an addendum sits alongside it and adds. That matters when the original contract has been distributed widely, referenced in financing documents, or built into an operations system, because an addendum leaves every existing reference accurate. It also matters for precedence: an addendum needs to say clearly what happens when its new terms brush up against terms already in the contract.

When to Use This Template

  • You are adding a service, product line, location, or property to an existing contract
  • The original agreement needs a new schedule, exhibit, annex, or fee table appended to it
  • A regulatory or policy requirement — data protection, security, insurance — arose after signing
  • A landlord or vendor needs to add rules or house policies without reopening the base contract
  • You want new terms recorded without disturbing language other documents already reference
  • Both parties agree on something extra and want it enforceable under the written-modification clause

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Full text of the template. Fields in [BRACKETS] are placeholders you fill in.

Contract Addendum

  1. 1. 1. Parties and Underlying Agreement

    This Addendum (the "Addendum") is made effective as of [ADDENDUM EFFECTIVE DATE] between [PARTY A NAME], a [ENTITY TYPE] located at [PARTY A ADDRESS], and [PARTY B NAME], a [ENTITY TYPE] located at [PARTY B ADDRESS] (each a "Party" and together the "Parties"). The Parties are parties to that certain [UNDERLYING AGREEMENT TITLE] dated [UNDERLYING AGREEMENT DATE] (the "Agreement"). Capitalized terms not defined in this Addendum have the meanings given in the Agreement. Each Party represents that the person signing below is authorized to bind that Party.

  2. 2. 2. Purpose and Scope of This Addendum

    The Parties wish to add terms to the Agreement that it does not currently address. The subject of this Addendum is [SUBJECT, e.g., additional services at a second location, a data processing annex, a new equipment schedule, seasonal pricing]. This Addendum adds obligations to the Agreement and does not delete, rewrite, or replace any existing provision of the Agreement. Any change to language already contained in the Agreement must be made by a separate written amendment signed by both Parties.

  3. 3. 3. Incorporation by Reference

    This Addendum is incorporated into and made a part of the Agreement as if fully set out in it, and the Agreement and this Addendum will be read and construed together as a single contract. All general provisions of the Agreement — including confidentiality, insurance, limitation of liability, indemnification, notices, assignment, dispute resolution, and governing law — apply to the subject matter of this Addendum unless this Addendum expressly states otherwise. References in the Agreement to "this Agreement" are deemed to include this Addendum from the Addendum Effective Date forward.

  4. 4. 4. Additional Terms and Obligations

    The following additional terms apply as of the Addendum Effective Date: [ADDITIONAL TERMS — describe the new services, goods, locations, deliverables, standards, or obligations in specific detail]. The Party responsible for performing each added obligation is [RESPONSIBLE PARTY], and performance standards, acceptance criteria, and deadlines for the added obligations are set out in Attachment [ATTACHMENT LETTER]. The added obligations are subject to the same service levels, warranties, and remedies stated in the Agreement, except as modified in Attachment [ATTACHMENT LETTER].

  5. 5. 5. Additional Fees and Payment

    The consideration for the additional terms is [ADDITIONAL FEE AMOUNT], payable as [PAYMENT STRUCTURE, e.g., a one-time charge, an increase of $[AMOUNT] to the recurring monthly fee, an hourly rate of $[RATE], or "no additional charge"]. Amounts due under this Addendum are invoiced and paid on the same terms, methods, and late-payment provisions set out in the Agreement, unless different terms are stated here: [ALTERNATIVE PAYMENT TERMS, or "None"]. Fees under this Addendum are in addition to, and do not replace, the fees payable under the Agreement. All amounts are exclusive of applicable taxes.

  6. 6. 6. Term of This Addendum

    This Addendum begins on [ADDENDUM EFFECTIVE DATE] and continues until [ADDENDUM END DATE, or "the expiration or earlier termination of the Agreement"]. If this Addendum has an end date earlier than the Agreement, expiration of this Addendum ends only the added obligations and does not affect the Agreement, which continues in full force. Termination of the Agreement for any reason automatically terminates this Addendum on the same date. Either Party may terminate this Addendum alone by giving [ADDENDUM NOTICE PERIOD, e.g., 30 days] written notice, without terminating the Agreement.

  7. 7. 7. Effect on the Agreement

    Except for the terms added by this Addendum, the Agreement remains unchanged and in full force and effect, and the Parties ratify and confirm it. Nothing in this Addendum waives any right, claim, or remedy that either Party has under the Agreement, whether it arose before or after the Addendum Effective Date. Execution of this Addendum is not a course of dealing that requires either Party to accept future additions, and it does not create an obligation to negotiate further addenda.

  8. 8. 8. Conflict and Order of Precedence

    If a term of this Addendum conflicts directly with a term of the Agreement, the term of this Addendum controls solely with respect to the subject matter described in Section 2, and the Agreement controls in all other respects. Where a provision of this Addendum can be read consistently with the Agreement, both will be given effect. If this Addendum conflicts with a prior addendum covering the same subject matter, this Addendum controls. Attachments to this Addendum rank below the body of this Addendum unless an attachment expressly states otherwise and is signed by both Parties.

  9. 9. 9. Attachments and Exhibits

    The following attachments are part of this Addendum: [LIST ATTACHMENTS, e.g., Attachment A — Additional Scope of Work; Attachment B — Revised Fee Schedule; Attachment C — Site List]. Attachments added to the Agreement by this Addendum do not replace existing exhibits of the Agreement and are lettered or numbered so that they do not conflict with existing exhibit designations. Where an attachment contains a form, checklist, or specification, it is binding to the same extent as the body of this Addendum.

  10. 10. 10. Representations and Authority

    Each Party represents and warrants that it has full power and authority to enter into this Addendum; that this Addendum has been duly authorized by all necessary action; that no third-party consent, lender approval, or governmental authorization is required other than any obtained and attached here; and that it is not in material default under the Agreement as of the Addendum Effective Date except as disclosed in writing. Each Party further represents that it has the resources, licenses, and permits necessary to perform the obligations added by this Addendum.

  11. 11. 11. Governing Law and General Provisions

    This Addendum is governed by the laws of the State of [GOVERNING STATE], without regard to conflict of laws rules, and the notice, venue, and dispute resolution provisions of the Agreement apply to this Addendum. Any further addition or modification must be in writing and signed by both Parties. If any provision of this Addendum is held unenforceable, the remainder remains in effect and the unenforceable provision will be limited only to the extent required. This Addendum binds and benefits the Parties and their permitted successors and assigns.

  12. 12. 12. Counterparts and Signatures

    This Addendum may be signed in counterparts, each of which is an original and all of which together are one instrument, and electronic or scanned signatures have the same effect as originals. By signing below, each Party confirms it has read this Addendum, understands the obligations it adds, and agrees to be bound as of the Addendum Effective Date. PARTY A: [PARTY A NAME]. Signature: ______________________. Printed Name: [SIGNER NAME]. Title: [TITLE]. Date: [DATE]. PARTY B: [PARTY B NAME]. Signature: ______________________. Printed Name: [SIGNER NAME]. Title: [TITLE]. Date: [DATE].

  13. 13. Disclaimer

    This template is provided for general informational purposes only and is not legal advice. Whether an addendum is enforceable and how it interacts with the underlying contract depend on state law and on the specific integration, precedence, and modification clauses in your agreement. Certain subject matter — consumer terms, residential leases, healthcare, and regulated data — carries additional requirements. Review and adapt this document for your own facts and consult a licensed attorney before relying on it. Use of this template does not create an attorney-client relationship with ScanContract.

Key Clauses Explained

What each important clause does — and what to watch out for before you sign.

Incorporation by Reference

Makes the addendum part of the underlying contract so both documents are enforced together.

Confirm that the general protections you care about — liability caps, insurance, indemnity, dispute resolution — actually carry across to the new subject matter. Some addenda quietly opt out of them. If the added work is riskier than the original scope, check whether the existing liability cap still makes sense for it.

Additional Terms and Obligations

Describes the new work, goods, sites, or standards being added to the relationship.

The addendum should say who performs the added obligation and what acceptance looks like, not just that it exists. If you are the party taking on new work, make sure deadlines and service levels are stated here rather than inherited by default from a section written for something else.

Additional Fees

Sets what the added scope costs and whether it is one-time or recurring.

Watch for an addendum that adds substantial obligations at "no additional charge" — that is fine if it is a genuine concession, and a problem if it was overlooked. On the buying side, confirm the new fee is additive rather than replacing an existing discount, and check whether it changes the renewal baseline.

Term of the Addendum

States how long the added terms last and whether they can end separately from the contract.

An addendum with no end date usually runs for the life of the contract, including through automatic renewals. If the addition is a pilot, a seasonal arrangement, or a single project, put an end date in. Also confirm which party can cancel the addendum alone without killing the whole agreement.

Conflict and Order of Precedence

Resolves what happens when the addendum and the original contract point in different directions.

This clause is the one that turns a supposedly additive document into a stealth amendment. If the addendum says it controls over the entire agreement rather than only its own subject matter, you have effectively rewritten the contract. Narrow it to the subject described in the purpose section.

Effect on the Agreement

Confirms the original contract text is untouched and no rights are waived.

If an existing dispute or unpaid invoice is open, make sure signing this addendum does not read as accepting the current state of performance. Language like "the parties acknowledge all obligations to date have been satisfied" does not belong in an addendum unless you mean it.

Attachments and Exhibits

Identifies the schedules, scopes, and specifications that come with the addendum.

Attachments referenced but not attached are one of the most common defects in signed addenda. Before signing, confirm every listed attachment physically exists, is dated, and does not reuse an exhibit letter already assigned in the original contract.

Frequently Asked Questions

What is the difference between an addendum and an amendment?
An addendum adds new material to a contract that the contract did not previously cover, and leaves the original text exactly as written. An amendment modifies terms that are already in the contract, deleting or replacing existing language such as a rate, a date, or a scope description. A useful test: if you can describe the change as "and also…", it is an addendum; if you have to describe it as "instead of…", it is an amendment.
Does an addendum need to be signed by both parties?
Yes, in virtually all cases. Because an addendum creates new obligations, it needs the same mutual assent as the underlying contract, and most agreements require any supplement to be in writing and signed. Electronic signatures are generally acceptable. A document one party circulates and the other never signs is a proposal, not part of the contract.
Can an addendum be added after a contract is signed?
That is precisely what it is for. An addendum is prepared after execution, references the original agreement by title and date, and takes effect on the date the parties choose. What it cannot do is retroactively rewrite something that already happened, so if you need a change to apply to past performance, say so expressly and expect that to be negotiated.
Which controls if the addendum and the contract disagree?
Whatever the precedence clause says, which is why that section deserves a careful read. Most well-drafted addenda control only over their own subject matter and leave the original contract governing everything else. If the addendum claims priority over the entire agreement, you are looking at an amendment wearing an addendum label.
Do I need a lawyer to write an addendum?
For a straightforward addition — an extra site, an extra deliverable, a revised fee table — a clear written addendum signed by both parties is usually enough. Bring in an attorney when the addition changes risk allocation, touches regulated data or healthcare, affects financing or a guaranty, or when the underlying contract has an unusual integration clause that limits what supplements can do.

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