A 645 credit score won’t stop you from buying a house. It will change what the house costs you every month, sometimes by $200 or more on the exact same property, the same down payment, and the same loan officer.
Fair credit sits roughly in the 580-to-669 band on the FICO scale. Lots of lenders will happily write that loan. The catch is that mortgage pricing is stacked in layers, and your score decides which layer you land in. Once you can see those layers, a quote stops looking like a magic number and starts looking like something you can argue with.
What “fair credit” means to a mortgage underwriter
The consumer-facing labels are tidy: 300–579 poor, 580–669 fair, 670–739 good, 740–799 very good, 800+ exceptional. Mortgage pricing is messier. Lenders pull three scores and use the middle one, and many use older FICO models (Score 2, 4, or 5) rather than the version you see in a banking app. A 668 on Credit Karma might come back as 651 on the report your loan officer pulls. That gap matters, because pricing buckets are 20 points wide.
Minimums vary by program. Conventional loans typically need a 620 middle score. FHA goes down to 580 with 3.5% down, and 500–579 with 10% down at some lenders. VA has no official floor, though most lenders set one around 580 to 620.
The real price tag, in points and dollars
Conventional loans price credit risk through loan-level price adjustments, or LLPAs. These are percentage-of-loan fees baked into your rate. Rough numbers for a 30-year loan at 75% loan-to-value look like this:
- 760+: about 0.375 points
- 740–759: about 0.500 points
- 700–719: about 1.000 points
- 680–699: about 1.250 points
- 660–679: about 1.750 points
- 640–659: about 2.750 points
- 620–639: about 3.000 points
One point equals 1% of the loan. On a $350,000 mortgage, the gap between the 640–659 bucket and the 760+ bucket is roughly 2.375 points, or about $8,300. Rolled into the rate instead of paid upfront, that’s somewhere near 0.6% to 0.7% higher — a 6.4% quote drifting up to about 7.05%. On a $350,000 loan that’s around $150 a month, or $54,000 over thirty years.
To see what the top of that ladder looks like, it helps to understand what a 760+ score really buys you in rate and fee savings. The gap is real, and it’s mostly about where you land in the grid above.
Loan programs where fair credit stings less
Not every loan prices credit the same way, and picking the right program can offset a mediocre score better than three months of credit repair.
FHA
FHA leans on mortgage insurance instead of credit-based pricing. A 600-score borrower and a 700-score borrower often get nearly identical FHA rates. You pay for it elsewhere: a 1.75% upfront mortgage insurance premium and an annual premium around 0.55% on most 30-year loans with less than 10% down. On $350,000 that’s roughly $1,925 upfront and $160 a month.
VA and USDA
VA loans skip the credit-based rate grid entirely and cap the funding fee structure by down payment and service history. USDA similar — the guarantee fee doesn’t shift much with score. If you qualify for either, the fair-credit penalty largely evaporates.
Conventional with a bigger down payment
LLPAs shrink as loan-to-value drops. At 60% LTV, the 640–659 bucket drops from about 2.75 points to roughly 1.5. Putting more down can be cheaper than paying the fee.
Finding your credit penalty on paper
Every lender must give you a Loan Estimate within three business days of application. Page 2, Section A, line for “Loan Costs” — that’s where discount points show up, and a fair-credit adjustment often gets buried there or folded into the rate itself. Ask directly: “What is my LLPA, and what would this quote be at a 760 score?” A good loan officer will answer in about ten seconds. One who dodges is telling you something.
The full mechanics are worth learning, and this walkthrough of how mortgage rates are determined shows exactly where each adjustment lands on a real quote.
Five levers that move your rate as much as your score
Credit is one input. These often swing the number harder:
- Loan-to-value. Moving from 95% to 80% LTV can cut pricing by 0.75 points or more.
- Discount points. Buying the rate down costs 1% of the loan per point and typically cuts the rate about 0.25%.
- Lender overlays. Two lenders can price the same 645 score a full half-point apart. Shopping three or four is standard practice, not a red flag.
- Debt-to-income ratio. A 49% DTI with thin reserves prices worse than a 38% DTI with six months of savings.
- Property type. Condos, manufactured homes, and 2–4 unit properties carry their own add-on fees.
Region matters too. A plan built around beating your state’s average mortgage rate will often get you further than chasing twenty extra credit points.
Credit moves that pay off in 60 to 90 days
You can’t fix a score overnight, but some changes hit fast because payment history and utilization are recalculated every cycle.
Drop revolving balances below 10% of your limits. Utilization is about 30% of your FICO score, and the jump from 45% to 8% on two cards can be 30 to 40 points. Dispute genuine reporting errors — a collections account that isn’t yours can be removed in three to five weeks, and a rapid rescore through your lender can push the update through in days rather than a month. Leave old accounts open. Ask a family member with a clean, long-standing card to add you as an authorized user, which can lift a thin file considerably.
What not to do: open a new card for the furniture, finance a car, or co-sign a sibling’s loan in the six months before you apply. Each of those can cost more in rate than it saves in convenience.
When waiting six months actually pays
Run the numbers before you assume waiting is smart. Suppose you’re at 638 and a program of paying down two cards and disputing one error would get you to 682. That move from the 620–639 bucket to the 680–699 bucket is worth roughly 1.75 points on a $350,000 loan, about $6,100. If waiting costs you six months of rent at $1,900 — $11,400 — and home prices in your area are climbing 4% a year, waiting is a losing trade.
Reverse the scenario. If you’re at 658 and one more clean payment cycle puts you in the 660–679 bucket, that’s worth about $3,500 for a 45-day delay. Take the delay. The decision is arithmetic, not principle.
Shop the quote, not the headline rate
Fair-credit borrowers get hurt most by not shopping. Advertised rates are usually built on a 740 score, 20% down, and a single-family home — a profile that isn’t yours. This is exactly why the quote you see isn’t the one you get, and why the only number worth comparing is a written Loan Estimate with your actual credit score, LTV, and property address filled in.
Get three of them, same day if possible, and compare the rate plus total points and fees side by side. A 645-score borrower who collects four estimates routinely beats a 720-score borrower who takes the first offer, sometimes by half a point. Your score sets the starting line. Where you finish depends on how many lenders you make compete for the loan.