Loan-to-Value: The Ratio That Decides Your Mortgage Terms
What a 100% loan-to-value mortgage means, why the 80% LTV line triggers PMI, and how the ratio gets re-measured when you refinance — with worked examples
A 100% loan-to-value mortgage is a loan for the entire value of the property — no down payment, no starting equity. The ratio itself is just the loan divided by the value: borrow $350,000 against a $350,000 home and you're at 350,000 ÷ 350,000 = 100% LTV. Two mainstream U.S. programs actually lend at that level: VA loans for eligible veterans and service members, and USDA loans on properties in designated rural areas. Neither charges private mortgage insurance — the VA takes a one-time funding fee instead, and USDA charges an upfront guarantee fee plus an annual fee. Outside those two, 100% financing is rare: a handful of credit unions and niche lenders offer it, usually only to borrowers with excellent credit.
What makes 100% LTV risky isn't getting approved — it's what happens the day after. With zero equity, any decline in value puts you underwater. If that $350,000 home slips just 3% — 350,000 × 0.03 = $10,500 — it's worth $339,500 while the debt is still $350,000, and the ratio becomes 350,000 ÷ 339,500 = just over 103%. Owing more than the home is worth means a sale requires bringing cash to closing, and most refinances are off the table. Every other mortgage number — your rate tier, whether you pay PMI, how much cash you can pull out later — hangs on this same ratio, so it pays to know exactly how lenders read it.
What LTV means on a mortgage
LTV = loan amount ÷ property value × 100
For a purchase, lenders set "property value" at the lower of the contract price and the appraised value — so an appraisal that comes in low pushes the LTV up even though your offer hasn't changed. Take the standard case: a $320,000 mortgage on a $400,000 home is 320,000 ÷ 400,000 = 80% LTV. Equity is the mirror image: 400,000 − 320,000 = $80,000, which is 80,000 ÷ 400,000 = 20% of the value. LTV and equity percentage always sum to 100. The loan-to-value ratio calculator returns both, along with the largest loan the property can carry before mortgage insurance kicks in.
A second version of the ratio trips people up: combined LTV (CLTV) counts every lien on the property, not just the first mortgage. The classic piggyback structure — that same $320,000 first mortgage plus a $40,000 home-equity loan on the $400,000 house — keeps the first mortgage at 80% and dodges PMI, but the combined ratio is (320,000 + 40,000) ÷ 400,000 = 360,000 ÷ 400,000 = 90%. Lenders underwrite to both figures, because total leverage determines how much cushion exists if the property has to be sold in foreclosure. The 2008 crisis made the distinction brutal: national home prices fell roughly 30%, and borrowers stacked past 100% CLTV were underwater even where the first mortgage alone had looked conservative.
The 80% threshold, and what crossing it costs
Conventional loans above 80% LTV require private mortgage insurance — a policy that protects the lender, not you, and gets billed to you every month. Concretely: put 10% down on a $400,000 home and the down payment is 400,000 × 0.10 = $40,000, leaving a 400,000 − 40,000 = $360,000 loan at 360,000 ÷ 400,000 = 90% LTV. At an annual rate of 0.75% — the default in the PMI calculator — the premium is 360,000 × 0.0075 = $2,700 a year, or 2,700 ÷ 12 = $225 a month. Actual rates run from about 0.3% for strong-credit borrowers to 1.5% at the risky end of the pricing grid — on this loan, anywhere from 360,000 × 0.003 = $1,080 to 360,000 × 0.015 = $5,400 per year.
The threshold works in both directions. On that $400,000 home, the largest loan that avoids PMI entirely is 400,000 × 0.80 = $320,000. And once you're paying PMI, the Homeowners Protection Act of 1998 defines the exit: you can request cancellation when the balance reaches 80% of the original value — on the original amortization schedule, or earlier with a new appraisal showing appreciation — and the lender must terminate it automatically at 78%. For the 90% borrower above, the request point arrives after paying the balance down by 360,000 − 320,000 = $40,000. FHA loans play by harsher rules: those originated after June 3, 2013 with less than 10% down carry their mortgage insurance premium for the life of the loan, and refinancing into a conventional mortgage is the only way out.
PMI is the visible cost of a high ratio; the quieter one is pricing. Conventional lenders apply loan-level pricing adjustments in LTV bands, and each 5-point step up in LTV can add 0.125 to 0.25 percentage points to the interest rate. Two buyers with identical credit scores can be quoted different rates on the same house purely because one is borrowing 75% of its value and the other 85%.
Where each loan program draws its line
Every program's maximum LTV is just 100 minus its minimum down payment — for FHA, 100 − 3.5 = 96.5.
| Program | Minimum down | Maximum LTV | Mortgage insurance |
|---|---|---|---|
| Conventional, first-time buyer programs | 3% | 97% | PMI above 80% LTV, cancellable |
| Conventional, standard | 5% | 95% | PMI above 80% LTV, cancellable |
| FHA | 3.5% | 96.5% | 1.75% upfront + 0.15–0.75% annual; life-of-loan below 10% down |
| VA | 0% | 100% | None — one-time funding fee |
| USDA | 0% | 100% | Upfront guarantee fee + annual fee |
Jumbo loans sit outside the table: they typically demand 10% to 20% down, so their effective LTV ceiling is lower than any government-backed program's.
Refinancing: the ratio gets re-measured
At refinance, the denominator resets. LTV is calculated against a fresh appraisal, not what you paid — which means appreciation does the same work as principal payments, only faster. Keep the $320,000 balance from earlier and let the home appraise at $450,000 instead of $400,000: the ratio drops to 320,000 ÷ 450,000 = about 71%, deep inside the best pricing tiers, and — if the loan carried PMI — comfortably below the removal threshold. This is why a refinance after a strong market run can kill PMI even when the balance has barely moved.
The thresholds tighten when you want cash out. Conventional and FHA cash-out refinances cap at 80% LTV — you must leave 20% equity behind after the new loan funds — while VA cash-outs allow up to 90%. In the opposite, underwater case, an ordinary refinance is generally unavailable because the new lender would be undersecured; FHA streamline refinances, which skip the appraisal entirely, are the main route to a lower rate with LTV above 100%. Whatever the scenario, weigh the closing costs — typically 2% to 5% of the loan amount — against what the new loan actually saves.
The one input you control
All of the above is arithmetic on two numbers, and at purchase you only control one of them: the loan amount, through your down payment. On a $400,000 target, 20% down means 400,000 × 0.20 = $80,000 in cash, while the FHA minimum of 3.5% means 400,000 × 0.035 = $14,000. Between those two figures sits every trade-off in this post — PMI or no PMI, standard pricing or the best tier, a thick equity cushion or a thin one. The down payment calculator turns whichever target you choose into a total cash-needed figure with closing costs included, plus the monthly savings required to get there by your purchase date.
LTV gets measured at three moments: the day you buy, the month your balance crosses the 80% and 78% marks, and any time you refinance. Run your own figures before a lender runs theirs — the rest of the mortgage toolkit lives on Quanta. One parting diagnostic: when a lender's LTV disagrees with yours, the numerators almost never differ. It's the denominator — they're dividing by the appraisal while you're dividing by the contract price. If the gap survives that explanation, send us both sets of numbers and we'll trace where they diverge.