Non-Occupant Co-Borrower FHA 2027 Calculator (Parent Co-Sign)

Calculate how much extra loan amount you qualify for with a non-occupant FHA co-borrower (parent, grandparent). See blended DTI, maximum loan, and the extra purchasing power. Free, private.

Primary borrower monthly income ($)

Primary monthly debts ($)

Co-borrower monthly income ($)

Co-borrower monthly debts ($)

FHA mortgage rate (%)

Loan term (years)

Monthly taxes + insurance ($)

Max back-end DTI (%, FHA 43-50)

Extra loan with co-borrower

vs solo qualification

Primary only — max loan

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DTI %

With co-borrower — max loan

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Combined DTI %

Combined monthly income

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Both borrowers

Metric	Primary only	With co-borrower

Note: The non-occupant co-borrower must be a relative (blood, marriage, adoption, or significant family-like relationship). Both borrowers are equally liable for the debt. The co-borrower\'s name typically appears on title unless explicitly excluded. To remove the co-borrower later, the primary borrower must refinance the loan into their name only — they\'ll need to qualify solo at that time. FHA loan limit for 2027 is ~$498,257 baseline / $1,149,825 high-cost area.

What is a non-occupant co-borrower on an FHA loan?

A non-occupant co-borrower is a person — typically a parent, grandparent, sibling, aunt/uncle, or other close relative — who signs as a full co-borrower on an FHA mortgage but does NOT live in the home. FHA explicitly allows this structure (HUD Handbook 4000.1, Section II.A.5) when the co-borrower has a family relationship to the occupant. The co-borrower's income, credit, and assets are combined with the primary borrower's for qualification, allowing a larger loan than the primary borrower could get alone.

This structure is most useful for: (1) young adults whose income is insufficient for the local market but whose parents have strong financials, (2) recent graduates with high student debt and entry-level salaries, (3) self-employed buyers whose 2-year income hasn't seasoned yet but have W-2 family support, (4) divorcing borrowers needing to qualify on one income but with family willing to backstop temporarily.

How FHA calculates blended DTI

FHA combines both borrowers' incomes and debts into a single DTI calculation. The combined income must support:

Front-end DTI (housing only): typically 31% max, can stretch to 40% with compensating factors
Back-end DTI (housing + all other debts): typically 43% max, stretches to 50%+ with compensating factors (high credit score, reserves, low LTV)

Both borrowers' existing debts count: car payments, student loans, credit card minimums, existing mortgages, alimony. The co-borrower's existing housing payment (their own rent or mortgage) is included as a debt — this is the catch. If your parent has a $3,000 mortgage already, that $3,000 hits the DTI calculation alongside your debts. Often the co-borrower's income only nets 50-70% of the income contribution because of their own housing cost.

Limits, restrictions, and gotchas

Several restrictions to know:

Lower credit score wins. FHA uses the lower of the two borrowers' middle scores for qualification. If primary is 620 and co-borrower is 800, FHA uses 620. Co-borrowers help with income, not credit.
FHA loan limit applies. 2027 baseline is ~$498,257 (high-cost up to $1,149,825). The combined income may qualify you for a larger loan, but it's capped at the FHA limit. If you need more than that, look at conventional Fannie Mae's "income-flexible" non-occupant co-borrower rules.
Both on title. The co-borrower's name typically appears on the deed unless explicitly excluded by a separate Quit Claim Deed at closing. This affects probate, divorce settlements, and the primary's ability to refinance.
Mortgage interest deduction. Only the person who actually pays the mortgage and itemizes can deduct the interest. If parent co-borrower pays nothing but signs, they get no deduction.

How to use this calculator

Enter the primary borrower's monthly income and existing debts, then the co-borrower's monthly income and debts (including their existing housing payment). Enter the FHA mortgage rate, term, and estimated monthly taxes + insurance for the new property. Set your max back-end DTI (FHA allows 43% standard, 50% with compensating factors).

The calculator returns: (1) max loan amount the primary borrower could qualify for solo, (2) max loan amount with the co-borrower's income added, (3) the extra purchasing power, and (4) combined DTI calculation. Use this to evaluate whether adding a parent as co-borrower makes the deal possible — and to budget for the refinance to remove them in 2-3 years.

Removal strategy: plan to refinance into your name only within 2-3 years. By then your income should have grown, your debt may be lower, and you can release the co-borrower from liability. Budget $3,000-$8,000 in refinance costs and verify the FHA Streamline Refinance program is available (simpler underwriting, no income re-verification in some cases).

Source: HUD Handbook 4000.1 (FHA Single Family Handbook), Section II.A.5 — Borrowers and Co-Borrowers — updated May 2026.