Buying on a Single Income
Lenders are not allowed to discriminate based on marital status, but a single-income household gets a structurally smaller approval than a two-earner household with the same total.
Why Single-Income DTI Is Harder
Same DTI, less margin. A couple earning $60k each ($120k total) with a $2,000 housing budget has two incomes covering the risk. A single earner at $120k has one income. If either partner in the couple loses a job, the mortgage still gets paid. If the single earner loses a job, the house is at risk.
Lenders price that risk into how strictly they apply the 28/36 rule. A single-income buyer at 36% DTI tends to be pushed to prove more reserves than a dual-income buyer at the same ratio.
Practical Adjustments
Target front-end DTI of 25%, not 28%. On $120k single income, that is $2,500/month housing budget instead of $2,800.
Keep 9 months of reserves, not 6. You cannot lean on a partner's paycheck during a gap.
Avoid ARMs. Variable rate mortgages assume you can absorb a payment shock with additional income. A single-income buyer cannot.
Disability insurance is not optional. Long-term disability (not just life insurance) is the single most overlooked protection for single-income owners.
Co-Signers and Non-Occupant Co-Borrowers
Some lenders allow a parent or sibling to co-sign the loan without living in the house. This boosts your approved amount but makes them equally liable. If you miss a payment, their credit suffers. Use with caution, and only with a parent who can afford the house themselves if you cannot.
The Math Example
Single earner, $110k salary, $300/month car payment, 6.75% rate, 20% down, 1.1% tax:
- At 36% back-end: approves to $340k home.
- At 28% front-end: comfortable at $295k home.
- At 25% front-end (recommended for single income): $265k home.
That $75k gap between lender ceiling and recommended purchase is what keeps you out of "house poor" territory when life happens.