If you cosigned a student loan and now want to buy a house, expect the loan to shrink how much mortgage you qualify for. Lenders treat the cosigned balance as your own debt, count the full monthly payment against your debt-to-income ratio, and read any late payment on your credit report as if you were the one who missed it. The effect can be significant, but there is a well-established way to get the debt excluded from the calculation if someone else has been paying it.
How Lenders Count the Cosigned Payment
Every mortgage application turns on your debt-to-income ratio: total monthly debt payments divided by gross monthly income. A cosigned student loan gets folded in at its full monthly payment amount, no matter who actually writes the check each month.
The ceiling depends on the program. Manually underwritten conventional loans backed by Fannie Mae cap at a 36 percent total DTI, stretching to 45 percent for borrowers with strong credit and reserves, and loans run through Fannie Mae’s automated underwriting can be approved up to 50 percent.1Fannie Mae. Debt-to-Income Ratios FHA uses a 31 percent front-end ratio for housing costs and a 43 percent back-end ratio for all debts combined.2FHA.com. FHA Debt-to-Income Ratio Requirements
The dollar impact is easy to see. If you earn $6,000 a month and your lender caps DTI at 45 percent, your total debt payments can run up to $2,700. A cosigned loan with a $500 monthly payment cuts your available room to $2,200 before the mortgage payment, property taxes, or homeowners insurance are even counted. Depending on rates, that $500 line item can translate to roughly $75,000 less in mortgage borrowing power. In a tight market that is an entire price tier gone.
What the Loan Does to Your Credit
The cosigned loan sits on your credit report as if you borrowed the money yourself. Bureaus track the balance, the payment history, and the age of the account. The balance adds to your total amounts owed, which drives roughly 30 percent of your FICO score, and a large remaining balance relative to the original loan can look like elevated risk to a mortgage underwriter.
Payment history is where the real damage lives. If the primary borrower is 30 days late, the delinquency lands on your report too. A single 30-day late can drop a previously strong score by 60 to 80 points according to FICO, enough to push you out of the interest-rate tier you were counting on, or out of qualification altogether. And you may not find out until after the fact, because the servicer contacts the primary borrower first.
Getting the Cosigned Loan Excluded From Your Application
This is the part worth planning around. Both Fannie Mae and FHA let lenders leave a cosigned student loan out of your DTI calculation if you can prove someone else has been paying it. The standard across programs is 12 consecutive months of on-time payments made entirely by the primary borrower, with none coming from your account.3Fannie Mae. Monthly Debt Obligations Freddie Mac has a similar exclusion for cosigned student loans with documented third-party payment history.4Freddie Mac. Guide Section 5401.2
Documentation is strict. You will need 12 months of bank statements or canceled checks from the borrower’s account showing each payment leaving their bank and arriving at the loan servicer. One payment from your account, or one late payment from theirs, and the lender counts the full debt against you.5HUD. FHA Single Family Housing Policy Handbook
If a home purchase is a year or two out, engineer this now. Have the primary borrower set up automatic payments from their own bank account and start saving the statements. Twelve months arrives faster than most people plan for, and clean records at application time can be the line between qualifying and being told to come back next year.
When the Payment Shows as $0
This one mostly applies to federal parent loans rather than cosigned private loans, but it comes up. Fannie Mae will let a lender qualify you using a $0 monthly payment if the borrower is enrolled in an income-driven repayment plan and documentation confirms the payment is genuinely $0.3Fannie Mae. Monthly Debt Obligations FHA does the opposite: when the credit report shows $0, the lender must use 0.5 percent of the outstanding balance as the monthly obligation.5HUD. FHA Single Family Housing Policy Handbook On a $40,000 balance, FHA imputes a $200 monthly payment when no one is actually paying anything.
Getting Off the Loan Before You Apply
Excluding the debt is one option. Removing your name is the permanent one, and there are two ways to do it.
Cosigner Release
Many private lenders offer a cosigner release once the primary borrower proves they can carry the loan alone. Terms vary, but the pattern holds: typically 12 to 24 months of consecutive on-time payments, proof of income, and a credit review showing the borrower would qualify on their own. Recent delinquencies, defaults, or hardship forbearance usually disqualify. Not every lender offers release and not every borrower will pass it, so check the promissory note for the specific requirements.
Refinancing Into the Borrower’s Name Only
When release is not on the table, the borrower can refinance the loan solo. The new loan pays off the old one, only they sign, and your obligation ends. The borrower needs enough credit and income to qualify without help. If the loan being refinanced is federal, moving it to a private lender means giving up income-driven repayment, deferment, and forgiveness programs, so the tradeoff has to be weighed. For a private-to-private refinance those protections were never in play.
Why Underwriters Take the Debt So Seriously
Cosigning is not a backup role. You are equally responsible for the full balance from the first day. Federal regulations require lenders to give you a notice before you sign, and the language is direct: “The creditor can collect this debt from you without first trying to collect from the borrower. The creditor can use the same collection methods against you that can be used against the borrower, such as suing you, garnishing your wages, etc.”6eCFR. 16 CFR 444.3 – Unfair or Deceptive Cosigner Practices
That is exactly how a mortgage underwriter sees the loan. The lender can pursue you directly without going after the student first, and the underwriter prices that risk into your file. If the loan does default, the consequences reach beyond your credit score: lawsuits, wage garnishment, and liens on property you own are all on the table.7Federal Student Aid. Student Loan Default and Collections FAQs For a mortgage applicant, that legal exposure is the reason the payment gets counted in full unless you can prove someone else has been carrying it clean for a year.