A cash-out refinance calculator answers three connected questions at once. How much equity can be released before the lender's loan-to-value ceiling stops you? What does the replacement mortgage cost each month? And what is the extracted cash really costing across the life of the new loan?
Arb Digital publishes this in its free tools library, and the boundaries against the adjacent tools matter because they are three genuinely different transactions. The mortgage refinance calculator assumes a like-for-like balance and answers whether a rate change is worth the closing costs. The HELOC calculator draws a revolving second lien and leaves the first mortgage untouched. This page replaces the first mortgage with a larger one and hands you the difference — which is the only one of the three where LTV limits, the size of the new balance and the cost of the equity you withdraw are the whole point.
What This Cash-Out Refinance Calculator Does
It starts from the LTV ceiling. Multiplying the home value by the maximum LTV gives the largest new loan a lender will write; subtracting the existing balance and the closing costs gives the maximum cash that can come out. That figure is the hard constraint, and it is the first thing worth knowing because it frequently rules the whole idea out.
It then builds the new loan you actually want — existing balance, plus the cash requested, plus closing costs if rolled in — amortises it at the new rate over the new term, and compares that payment against the one you have. The resulting LTV is shown so you can see how much headroom remains and whether mortgage insurance thresholds are in play.
The last figure is the one most calculators leave out: the additional interest across the life of the loan compared with simply keeping the existing mortgage to term. It combines the rate change and the term reset, and it is normally a much larger number than the cash withdrawn.
How to Use It
- Use a defensible home value. The lender's appraisal governs, not an online estimate. If the appraisal comes in lower than expected, the maximum cash falls by the LTV percentage of the shortfall.
- Enter months remaining, not the original term. A loan taken eight years ago on a 30-year term has 264 months left, and comparing against 360 would understate the cost of resetting the clock.
- Set the LTV cap your lender has actually quoted. Caps differ by programme, by occupancy and by credit profile, and a cash-out refinance is normally capped lower than a rate-and-term one.
- Decide how closing costs are paid. Rolling them in preserves cash today and adds to the balance you pay interest on for decades; paying them separately does the opposite.
- Compare the extra lifetime interest against what the cash is for. That comparison, not the monthly payment, is the decision.
The Formula / How It's Calculated
Four steps:
Maximum new loan = home value × maximum LTV. Maximum cash out = maximum new loan − current balance − closing costs when costs are rolled in. New loan amount = current balance + cash taken + rolled costs, and resulting LTV = new loan ÷ home value.
The payment uses the standard amortisation formula, M = P × r × (1 + r)n ÷ ((1 + r)n − 1), with r the monthly rate and n the number of months. Extra lifetime interest is the total interest on the new loan minus the interest still to be paid on the existing one.
Worked example, matching the values the page loads with. A $450,000 home with a $265,000 balance at an 80% LTV cap supports a new loan of $360,000, so the maximum cash available is $88,500 after $6,500 of costs. Taking $70,000 with the costs rolled in makes the new loan 265,000 + 70,000 + 6,500 = $341,500, a resulting LTV of 75.9%. At 6.5% over 30 years the payment is $2,158.51, against $1,475.63 on the existing 3.75% loan with 264 months left — a rise of $682.88 a month. Interest still owed on the old loan totals $124,566; interest on the new loan totals $435,564. The extra lifetime interest is therefore $310,998, or about $4,443 per $1,000 of cash extracted. The CFPB explains why the ratio itself matters in what is a loan-to-value ratio and how does it relate to my costs.
Separating the Rate Change From the Term Reset
The $310,998 figure above looks catastrophic, and reading it correctly requires pulling apart two effects that arrive together.
The first is the rate. Moving a balance from 3.75% to 6.5% costs money on every dollar, including the $265,000 that was already borrowed and was never the point of the exercise. This is the defining feature of a cash-out refinance and the reason it is a poor fit for anyone sitting on a low legacy rate: you cannot re-price only the new money, because the transaction replaces the entire first lien.
The second is the term. Replacing 264 remaining months with a fresh 360 adds eight years of payments regardless of rate. Even at an identical rate, restarting the clock increases total interest substantially, and it is the effect people consistently overlook because the monthly payment moves in the comforting direction.
Two adjustments follow directly. Shortening the new term — 20 or 25 years rather than 30 — removes most of the term-reset penalty at the cost of a higher payment. And when the existing rate is far below current rates, a second-lien product that leaves the first mortgage alone is often the cheaper structure, because it prices only the new borrowing. That is precisely the comparison the HELOC calculator and the home equity loan calculator exist for, and it is worth running before assuming a refinance is the right instrument.
The LTV Ceiling and What Sits Just Beneath It
Loan-to-value is the constraint that decides whether the transaction is possible at all, and it does more than cap the cash.
Cash-out refinances are almost always capped below rate-and-term refinances, because a lender writing a larger loan against the same collateral is taking more risk. Investment properties and second homes are capped lower again, and multi-unit properties lower still. The figure to enter is the one your lender quotes for your specific situation, not a general market number.
Pricing tightens as LTV rises even within the cap. Loans are priced in bands, and crossing a threshold moves you into a worse one — so a borrower who takes cash right up to the ceiling often pays a higher rate on the entire balance than one who stops a few points short. The trade is between the last few thousand dollars of cash and a rate applied to the whole loan for its full term, and that trade usually favours stopping short.
Below 80% LTV, mortgage insurance generally falls away on conventional loans. Extracting equity that pushes the new loan above that line can reinstate a monthly premium that the payment comparison will not show unless you add it, and that premium can persist for years. Anyone currently just under the threshold should treat 80% as a genuine wall rather than a guideline.
One more constraint applies regardless of arithmetic: the appraisal. Every number here depends on a value the lender determines, and a valuation below expectation reduces the maximum loan by the LTV percentage of the gap. On the worked example, an appraisal $20,000 low removes $16,000 of available cash.
What the Cash Is For Changes the Analysis Entirely
The calculator produces the same numbers regardless of purpose, but the numbers mean different things depending on what the money does.
Consolidating higher-rate debt. This is the case where the arithmetic can genuinely favour a cash-out refinance, because replacing short-term debt at a much higher rate with mortgage debt at a lower one reduces the interest paid. Two cautions apply. Unsecured debt becomes secured on the home, which converts a credit problem into a housing problem if payments fail. And stretching a balance that would have cleared in four years across thirty can increase total interest even at a much lower rate — the debt consolidation calculator is built to test exactly that.
Home improvement. Here the money produces an asset, though rarely one worth its full cost at resale. The relevant comparison is the extra lifetime interest against the value the work adds and the use you get from it.
Investment or consumption. Borrowing at a known long-term cost to pursue an uncertain return is a leveraged position, whatever it is called, and the security is the house. Spending equity on consumption converts a durable asset into a temporary one and adds three decades of interest to the price. The FTC's overview of home equity loans and home equity lines of credit covers the risks that attach to any borrowing secured on a home.
Arb Digital maintains a free library of mortgage, refinance and debt calculators so you can test a structure from several directions before committing to one.
Browse the Free Tools Talk to Arb DigitalCommon Mistakes to Avoid
- Judging the deal on the monthly payment — a lower payment achieved by resetting to a 30-year term can hide a six-figure increase in lifetime interest.
- Repricing a low legacy rate to reach new money — a cash-out refinance re-rates the entire balance, so a second lien is often cheaper when the existing rate is far below current ones.
- Taking cash right up to the LTV cap — the last few thousand dollars can push the loan into worse pricing that applies to the whole balance for its full term.
- Forgetting mortgage insurance above 80% — crossing that line can reinstate a monthly premium that no payment comparison shows unless you add it.
- Assuming an online valuation — the lender's appraisal governs, and a shortfall reduces available cash by the LTV percentage of the gap.
Related Free Tools From Arb Digital
Test a like-for-like refinance with the mortgage refinance calculator and its payback with the refinance break-even calculator, then compare second-lien routes using the HELOC calculator, the home equity loan calculator or the second mortgage calculator. The mortgage calculator and mortgage amortization calculator show the new loan month by month, and the debt consolidation calculator tests whether folding other balances in genuinely saves money. Everything else is in the free online tools hub.
Frequently Asked Questions
Multiply the appraised value by the lender's maximum loan-to-value, then subtract the existing balance and closing costs. On a $450,000 home with a $265,000 balance and an 80% cap, that leaves $88,500 after $6,500 of costs. The cap, not your equity, is normally the binding constraint.
A rate-and-term refinance replaces the existing balance with a similar one to change the rate or term. A cash-out refinance replaces it with a larger loan and pays you the difference, which raises the balance, raises the loan-to-value ratio and usually carries a lower LTV cap and different pricing.
They solve the same problem differently. A refinance re-prices the entire first mortgage, which is costly if the existing rate is far below current rates. A HELOC or home equity loan adds a second lien and prices only the new borrowing, but typically at a higher rate and often on a variable basis.
Because it combines two effects. The new rate applies to the whole balance, not just the cash withdrawn, and resetting a partly repaid loan to a fresh full term adds years of payments. Shortening the new term removes most of the second effect.
Rolling them in preserves cash at closing but means paying interest on them for the life of the loan, and it consumes part of the LTV headroom that would otherwise be available as cash. Paying separately costs more today and less overall.
Every figure scales down with it. Maximum cash falls by the LTV percentage of the shortfall, so a $20,000 low appraisal at an 80% cap removes $16,000 of available cash, and it may push the resulting ratio into worse pricing or reinstate mortgage insurance.
It can. On conventional loans, insurance generally falls away below 80% loan-to-value, so extracting equity that pushes the new loan back above that line can reinstate a monthly premium. That cost does not appear in a payment comparison unless it is added deliberately.
Tax treatment of mortgage interest depends on jurisdiction, on how the funds are used and on limits that change over time. This calculator makes no tax assumptions and applies no deduction, so any tax effect has to be assessed separately with someone qualified to advise on it.
This tool performs mortgage arithmetic on figures you supply, and every rate, cost and limit on this page is an input rather than an offer. It is not financial or tax advice, does not reflect any particular lender's terms or underwriting, and borrowing secured against your home carries the risk of losing it. Speak to a qualified adviser before acting.
