Adding a co-signer?. Create a co-signer agreement →
A co-signer agreement (also called a lease guaranty) is a signed promise by someone other than the tenant to pay the rent and other money the tenant owes under the lease if the tenant doesn't. It lets you approve an applicant who falls short on income or credit history without taking on all the risk. A good agreement names the lease it guarantees, says exactly what the co-signer is liable for and for how long, and is signed before the tenant moves in.
This guide covers when to ask for a co-signer, how to screen one, what the agreement should say, and the mistakes that make guaranties hard to enforce.
Co-signer vs guarantor vs co-tenant
The words get used loosely, so define them in your documents:
| Role | Lives in the unit? | Liable for rent? | Signs the lease? |
|---|---|---|---|
| Co-tenant | Yes | Yes, usually jointly with the other tenants | Yes |
| Co-signer | No | Yes, if the tenant doesn't pay | Signs the lease or a separate agreement |
| Guarantor | No | Yes, if the tenant doesn't pay | Usually signs a separate guaranty |
In practice, landlords use "co-signer" and "guarantor" for the same thing: a non-occupant who backs the lease. What matters is the language of the signed document, not the label. A separate guaranty is often cleaner, because the co-signer gets no right to live in the unit and the lease doesn't have to be rewritten.
When to ask for one
Common situations:
- Students or first-time renters with little rental or credit history
- Income below your standard, for example rent above a third of gross income (the rent-to-income ratio calculator checks this)
- Thin or damaged credit in an otherwise solid application
- A new job that hasn't produced pay stubs yet
Write down when you require a co-signer and apply it to every applicant the same way. Requiring co-signers only from some applicants, for reasons tied to a protected characteristic, violates the Fair Housing Act.
Adverse action notice
If you require a co-signer because of something in a consumer report, such as a credit or background check, federal law treats that as an adverse action. You must give the applicant a notice naming the reporting company and explaining their right to a free copy of the report and to dispute it (FTC, Using Consumer Reports: What Landlords Need to Know). See how to screen tenants for the full screening process.
Screen the co-signer like an applicant
A co-signer is only as good as their ability to pay. Ask for:
- A rental application with income, employment and contact details
- Written consent to a credit check
- Proof of income. Many landlords look for a higher multiple of rent than for tenants, because the co-signer also pays their own housing.
- Their address, and whether they live in your state. Collecting from someone out of state is harder.
Get the co-signer's consent before pulling any report, and use the same standards for every co-signer.
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What the agreement should say
| Clause | What it covers |
|---|---|
| Parties and lease | Co-signer's full name and address, the tenant's name, the property, and the lease date |
| Scope of liability | Rent only, or rent plus late fees, damage beyond the deposit, utilities the tenant owes, court costs and attorney's fees where the lease allows them |
| Cap, if any | A dollar limit or a number of months' rent, if you agree to limit it |
| Duration | The initial term only, or also renewals and any month-to-month holdover |
| Changes to the lease | Whether the co-signer must consent to renewals, rent increases or added tenants |
| Notice | How you'll tell the co-signer about missed rent, and their address for notices |
| No right to occupy | That signing gives the co-signer no right to live in or enter the unit |
| Signatures | Co-signer's signature and date; some landlords also get the tenant's acknowledgment |
Duration is the clause most often fought over. A guaranty that covers "the lease" may not clearly reach a renewal at a higher rent. If you want the co-signer to back renewals, say so, and send them a copy of each renewal. Otherwise, get a new signature at every renewal.
Our free co-signer agreement form includes these clauses. Fill it in, preview it and print it to sign alongside the lease.
Signing and keeping it
- Sign before move-in, at the same time as the lease or earlier. Once you've handed over keys, you've lost your leverage to get the signature.
- Give the co-signer copies of the lease and the agreement.
- Keep the signed original with the lease file, and update the co-signer's contact details each year.
- E-signing is fine to plan for if you e-sign the lease; the same rules apply, covered in is an electronic signature on a lease legally binding.
When the tenant stops paying
- Follow your normal late-rent steps with the tenant first: reminder, late fee, written notice. See what to do when a tenant pays rent late.
- Notify the co-signer in writing, as the agreement requires, with the amount owed and a copy of the ledger.
- If neither pays, any eviction is against the tenant. A claim for money against the co-signer is usually a separate step, often in small claims or civil court, depending on the amount and your state's rules.
Keep communication factual and documented. The co-signer is your backstop, not a collections target to pressure.
Alternatives to a co-signer
- A larger security deposit, where your state's deposit limit allows it
- Prepaid rent, where state law allows it
- A shorter lease term, or month-to-month, to limit exposure
- A third-party lease guarantee company, which the applicant pays for
Sources
Official sources cited above (checked 2026-10-28):
Frequently asked questions
Is a co-signer responsible for the whole lease?
Only for what the agreement says. A well-drafted guaranty states whether it covers rent only or also fees, damage and costs, any dollar cap, and whether it extends to renewals and month-to-month holdovers.
Do I need to send a notice if I require a co-signer?
If the decision was based on a credit or background report, yes. Federal law treats it as an adverse action, so you must tell the applicant which company supplied the report and explain their right to a free copy and to dispute it.
Adding a co-signer?
Fill in a co-signer agreement, preview it and print it to sign with the lease. Free, no account needed.
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