Your score is 601. You bought the house in 2019 at 5.1%, your payment feels about $300 a month too heavy, and every refinance ad you see assumes a 740 FICO. So the real question isn’t whether refinancing makes sense. It’s whether anyone will actually say yes.
They will, usually. But the approval won’t come from the same lender or the same rate sheet a prime borrower sees, and the gap between “approved” and “worth doing” can be uncomfortably wide. Here’s how underwriting actually treats a bruised credit file, and how to keep the cost from eating the benefit.
What a low score actually signals to an underwriter
Lenders aren’t grading your character. They’re pricing risk. A 590 tells them one or more of three things happened recently: a missed payment, a balance sitting near its limit, or a collection showing up. Which of those is true, and how old it is, changes the answer far more than the number itself.
Roughly, here’s how the bands behave:
- 580 to 619: FHA territory. Expect a rate about 1 to 2 percentage points above what a 740 borrower gets, plus mortgage insurance you can’t escape without 10% down.
- 620 to 659: Conventional loans open up, but loan-level price adjustments add real cost. A 640 borrower often pays around 1.25 points more than someone at 760 on the same loan.
- 660 to 699: Most lenders treat this as near-prime. Conventional approval is routine and the pricing penalty is smaller than people expect.
The story behind the score matters as much as the band. Eighteen months of clean payments after a divorce or a layoff reads very differently to an underwriter than a collection reported six weeks ago.
The three numbers that decide the file
Credit is one input. Three others usually carry more weight, especially when the score is thin or damaged.
Loan-to-value
If your appraisal puts you at 85% LTV, you’re paying mortgage insurance on a conventional loan and the rate adjustment is bigger. At 80% or below, the math improves sharply. It’s worth running a refinance loan-to-value calculator before you call anyone, because a low appraisal can quietly kill a deal that looked fine on paper.
Debt-to-income
Underwriters add your new housing payment to every minimum payment on your credit report, then divide by gross income. Conventional loans typically cap out at 50%, FHA often allows a bit more with compensating factors. If you’re carrying $600 in card payments, paying those balances down does double duty: it lowers DTI and usually lifts your score within a billing cycle. A refinance debt-to-income calculator will show you where the ceiling is before an underwriter does.
Reserves and payment history
Two months of housing payments in the bank is the usual benchmark. Someone with a 600 score, 20% equity and six months of reserves is a much easier approval than a 640 with nothing saved.
Which loan programs tolerate a low score
FHA is the most forgiving: 580 gets you 3.5% down, and scores between 500 and 579 are possible with 10% down at some lenders. VA has no official score minimum, though most lenders overlay 620 on top of it. USDA usually wants 640. Conventional bottoms out at 620. Above that, non-QM and portfolio lenders will underwrite on 12 to 24 months of bank statements or asset depletion rather than tax returns, which suits self-employed borrowers whose low score comes from a messy year rather than genuine credit problems.
The dollar cost of a low score, spelled out
Say you owe $280,000 on a 30-year loan. At 5.35% your principal and interest is about $1,564. At 6.10%, the same balance costs roughly $1,697. That’s $133 a month, or $1,596 a year, for a score that’s 120 points lower.
Now add the fees. A 1.5-point pricing adjustment on $280,000 is $4,200, and mortgage insurance at 0.55% annually is another $1,283 a year until you hit 20% equity. Suddenly the refinance you were pitched doesn’t break even for three or four years. That’s why the headline “one percent lower” pitch deserves a hard look rather than a handshake; the article on what a one percent rate drop actually saves runs the real arithmetic, fees included.
If PMI is part of your picture, model the full payment before you commit rather than guessing at it. There’s a PMI calculator walkthrough that shows how the insurance premium, the rate and the term stack up together.
What actually moves the needle in 60 to 90 days
You can’t rewrite history, but you can change how the file reads.
- Drop utilization below 10%. Paying a $4,000 balance down to $400 can lift a middle score by 30 to 50 points in one cycle. This is the single fastest lever most people have.
- Ask for a rapid rescore. If a collection was paid or an error is genuinely wrong, a lender can submit documentation for a rescore in 3 to 5 business days instead of waiting a month for the bureau to catch up.
- Don’t open new accounts. A car loan or a store card three weeks before application can drop you a band and change your pricing.
- Become an authorized user. A family member’s old, low-balance card added to your report can add years of average account age.
- Leave old collection accounts alone unless advised. Paying a four-year-old collection can restart its reporting clock and hurt more than it helps. Get advice specific to your state before you send a check.
Where to actually apply
Big banks are the worst fit here. Their automated systems decline anything below a cutoff, and loan officers rarely fight an automated no. Better odds come from specialty lenders, community banks and credit unions that portfolio their loans, and independent brokers with wholesale access to a dozen rate sheets. Knowing which of those refinance lenders genuinely approve bad credit files saves you from a week of hard inquiries and thin envelopes.
One practical note: every application is a hard pull, but mortgage inquiries within a 14 to 45 day window (depending on the scoring model) count as a single inquiry. Shop three or four lenders inside two weeks and the score damage stays minimal.
The paperwork that turns a borderline file into an approval
Most declines on low-score files aren’t about the score at all. They’re about an unexplained deposit, a gap in employment, or a debt the borrower forgot to disclose. Get ahead of it.
Write a short letter of explanation for every negative item: what happened, when it happened, and why it won’t recur. A medical collection with a one-paragraph note about a hospital stay and insurance lag is a completely different document than a silent blemish. Have two months of statements ready for every account you’ll use for reserves, and be prepared to document any deposit over 50% of your monthly income. If a family member is helping with closing costs, get the gift letter signed before underwriting asks.
And check your own credit reports at AnnualCreditReport.com first. Roughly one in five reports contains an error, and disputing a wrong balance or a collection that isn’t yours is free, fast, and occasionally worth 40 points. Do that before you apply, not after a denial.