Mortgage Recast Calculator
Lower your monthly payment without refinancing. See exactly how much a lump-sum principal payment reduces your P&I and total interest cost.
How to Use the Mortgage Recast Calculator
In under two minutes you'll know your new monthly payment, your total lifetime interest savings, and exactly how many months it takes to recoup the lump-sum investment — before you speak to your servicer.
Enter Your Current Loan Details
Input your remaining loan balance (from your most recent mortgage statement — not the original loan amount), your interest rate, and the number of years remaining on the loan. Use the rate slider to quickly explore how different rate scenarios affect the savings. The calculator uses these three inputs to compute your current monthly P&I payment, which becomes the baseline for the before/after comparison.
Set Your Lump-Sum Payment Amount
Use the slider or type the lump-sum amount you plan to apply to principal. The live hint beneath the field instantly shows your new balance and the percentage reduction as you drag. Most servicers require a minimum of $5,000–$10,000 — enter any amount above that minimum to see the full impact. Also enter the recast processing fee your servicer charges, typically $150–$500, which the calculator uses to compute your break-even point.
Set Your Planned Hold Period
Enter how many years you plan to stay in the home in the Break-Even Context section. This unlocks two additional outputs: total savings over your hold period, and whether your break-even point falls within or beyond that window. If the break-even is months but you plan to stay for years, the recast is clearly worthwhile. If the break-even extends beyond your planned ownership, the lump sum may be better deployed elsewhere.
Review All Outputs and Download Your Report
The results panel shows a colour-coded Before vs. After table across three key metrics — balance, monthly P&I, and total interest — plus six summary cards covering monthly savings, total interest saved, new balance, new payment, break-even, and hold-period savings. Click Download Report to save a professional PDF with the full analysis formatted for sharing with your loan servicer, financial advisor, or mortgage broker.
What the Recast Calculator Shows You
Six integrated outputs — from the instant monthly savings to the break-even timeline and cumulative hold-period gains — everything a homeowner needs to make a confident decision before calling their servicer.
Monthly Payment Reduction
The headline number: how much your monthly P&I payment drops after the recast. Displayed prominently in the green hero box at the top of the results panel, with the new balance and break-even months shown in the sub-line. This figure updates instantly as you adjust the lump-sum slider, so you can find the payment target that fits your budget.
Before vs. After Comparison Table
A structured four-column table showing loan balance, monthly P&I, and total remaining interest — before and after the recast — with a dedicated savings column. Colour-coded for instant readability: grey for the "before" column, green for "after," and blue for the savings delta. A totals row at the bottom shows lifetime interest savings in a single green highlight.
Break-Even Point
The number of months until your cumulative monthly savings exceed the total cash outlay (lump sum plus the recast fee). A break-even of 1–3 months is exceptional and very common with recasts. The card turns green when the break-even falls within your planned hold period, signalling the recast is financially justified. It turns red when the break-even extends beyond your hold horizon — a clear signal to reconsider.
Savings Over Your Hold Period
Total cumulative monthly savings over your planned years of ownership — your hold period multiplied by twelve months of lower payments. This figure converts the abstract monthly savings into a concrete total that is easier to compare against alternative uses of the same lump sum. A $200/month saving over 7 years equals $16,800 in reduced payments, which puts the decision in clear financial terms.
Total Lifetime Interest Saved
Interest savings calculated over the full remaining loan term — not just the hold period. Because you are paying the same rate on a permanently lower balance for the entire remaining term, every month generates lower interest charges than without the recast. This figure shows the maximum theoretical saving if you hold the loan to maturity, complementing the hold-period figure which shows the portion actually realised during your ownership.
Downloadable PDF Report
A professional PDF formatted for sharing with your loan servicer when initiating the recast request, or with a financial advisor comparing the recast against investing the lump sum. Includes the full loan details, before/after comparison table, all six summary metric cards, and a clean footer. All values are ASCII-safe and formatted consistently — no garbled characters across any device.
Mortgage Recast — Key Facts for U.S. Homeowners
Three Homeowners Who Should Model a Recast
A recast is not the right move for every homeowner — but for the right person at the right moment, it delivers permanent monthly relief with almost no friction. These three profiles capture the most common situations where a recast produces compelling results.
You've sold your previous home and have more equity than you needed for the down payment on the new one. Rather than leaving the surplus in a savings account or investing it at uncertain returns, a recast applies it directly to the principal on your new mortgage — immediately lowering the monthly payment and locking in a guaranteed return equal to your mortgage rate. For someone with $60,000 in leftover sale proceeds and a $450,000 loan at 6.5%, the monthly payment reduction and lifetime interest savings are measurable and certain, unlike market-based alternatives.
- Wait until your new loan has been active for at least 90 days before requesting a recast — most servicers require this minimum seasoning period
- Compare the guaranteed recast return (your mortgage rate) against the after-tax expected return on investing the same amount
- If you are keeping some proceeds as an emergency reserve, enter a smaller lump sum in the calculator to model the partial recast scenario
You are 3–7 years from retirement and your financial plan requires reducing fixed monthly obligations before income drops. A recast converts a lump sum — from a maturing CD, inherited funds, or an investment that's been de-risked — into a permanent monthly payment reduction that lasts for the remainder of the loan. Unlike paying extra principal without recasting (which shortens the term but keeps the payment the same), a recast immediately frees up cash flow — exactly what a pre-retiree needs. The lower fixed obligation also improves your post-retirement debt-to-income picture.
- Enter your planned retirement date as your hold period to see whether the recast produces savings over your remaining working years
- Confirm the lump sum will not impair your 6-month emergency reserve — the payment relief must not come at the cost of financial resilience
- If your mortgage rate is below 4%, compare the recast against keeping funds in a high-yield savings account or short-term treasuries at current rates
You refinanced in 2020–2022 and locked in a rate between 2.5% and 4%. Today's market rates are 6.5–7.5%, so refinancing is completely off the table — doing so would increase your payment substantially. But your income or expenses have changed and the current payment is straining your budget. A recast is the only way to lower your payment without abandoning your low rate. By applying a lump sum and recasting, you keep the sub-4% rate while reducing the monthly obligation permanently. This is exactly the scenario a recast was designed for.
- Enter your actual locked-in rate in the calculator — the savings will be smaller in absolute terms than for high-rate borrowers, but the rate preservation is the key advantage
- Model different lump-sum sizes to find the minimum payment you need to reach — work backward from a target monthly payment
- Ask your servicer whether they allow multiple recasts per year; if so, you can stage smaller payments over time rather than deploying all capital at once
7 Things Every Homeowner Should Know Before Requesting a Recast
A recast is simple — but the details matter. These tips help you confirm eligibility, use the calculator inputs accurately, and make the right decision about whether a recast beats alternative uses of your lump sum.
Confirm Eligibility Before You Make the Lump-Sum Payment
Call your loan servicer before sending a large payment and explicitly ask: "Is my loan eligible for a recast, and what are the requirements?" FHA, VA, and USDA loans are generally not eligible. Most conventional loans are, but your servicer may have specific seasoning requirements (how long the loan must have been active), minimum lump-sum thresholds, and maximum recasts per year. Making the payment first and then discovering the loan is ineligible leaves you with a lower balance but no payment reduction — and the money cannot be easily recovered.
Use Your Remaining Balance — Not the Original Loan Amount
The most common input error is entering the original loan amount instead of the current outstanding balance. If you took out a $400,000 mortgage five years ago and have been making regular payments, your remaining balance today might be $365,000. Enter $365,000 in the balance field — this is the balance that will be reduced by the lump sum, and the one on which your new payment will be calculated. Your mortgage statement shows the current principal balance; some servicers also offer payoff quotes through their online portal or by phone.
Understand What a Recast Does Not Do
A recast does not change your interest rate, shorten your loan term, remove PMI (though a lower LTV after the lump sum may allow you to request PMI cancellation separately), or consolidate other debts. It does one thing: lower your monthly principal and interest payment by recalculating it on a reduced balance at the same rate and for the same remaining term. If your goal is to pay off the loan faster or get a lower rate, a recast is not the right tool — extra principal payments or refinancing, respectively, are more appropriate.
A Recast and Extra Principal Payments Are Different Strategies
Making extra principal payments every month shortens your loan term but does not reduce your required monthly payment — you are still obligated to make the full original payment. A recast permanently lowers the required payment for the remaining term without shortening it. Some borrowers do both: recast to reduce the required payment, then continue making the old payment amount — which now includes an implicit extra principal component that accelerates payoff. This hybrid approach gives you both reduced obligation and accelerated payoff.
Time the Lump-Sum Payment Carefully
Most servicers process the recast after a lump-sum payment is received and applied to the principal. Make the payment at the beginning of a billing cycle rather than near the due date, and confirm with your servicer how long the recast takes to process (typically 30–45 days). Your payment for the month the lump sum is applied may remain at the old amount — the recasted lower payment typically begins the following month. Ask your servicer for the exact effective date so you can plan your budget accurately.
Check Whether Your LTV After Recasting Qualifies You to Cancel PMI
If your current LTV is near or above 80%, the lump-sum payment may push it below 80% — which is the threshold at which PMI can typically be cancelled on conventional loans. This is an additional benefit beyond the payment reduction: eliminating PMI can save $100–$300 per month on top of the recast savings. Calculate your new LTV after the lump sum (new balance divided by current home value) and contact your servicer to initiate a PMI cancellation request if you cross the 80% threshold. A current appraisal may be required.
Compare the Recast Against Your Mortgage Rate as a Return Benchmark
The financial return of a recast is deterministic: every dollar applied to principal saves exactly your mortgage rate in annualised interest — guaranteed, tax-treatment aside. A recast at 6.5% is mathematically equivalent to a 6.5% guaranteed return on the lump sum. Compare this against what you could reliably earn after tax elsewhere. If after-tax investment returns are likely to exceed your mortgage rate, investing may be preferable. If your mortgage rate is high relative to expected market returns, or if you value certainty and reduced cash-flow risk above maximum expected return, the recast wins. This calculator does not model the investment alternative — consult a financial advisor for a complete comparison.
Frequently Asked Questions
Everything you need to understand how a mortgage recast works, who qualifies, how the calculator models the savings, and how to make the right decision for your financial situation.
Important disclaimer: All results produced by the HomeExpertly Mortgage Recast Calculator are for educational and estimation purposes only and do not constitute financial, mortgage, legal, or tax advice. Calculations assume a fixed-rate mortgage, constant monthly payment, no additional principal payments, and that the full remaining term is preserved after recasting. Actual recast outcomes will vary based on your servicer's specific eligibility requirements, minimum lump-sum thresholds, processing fees, timing of payment application, and loan-type restrictions. This calculator does not account for income tax implications of mortgage interest deductions, opportunity cost of investing the lump sum, PMI cancellation thresholds, or escrow adjustment impacts on total monthly payment. Government-backed loans (FHA, VA, USDA) are generally not eligible for recasting. Always confirm eligibility and terms with your loan servicer before making a lump-sum payment, and consult a licensed mortgage professional and/or qualified financial advisor before making any financial decision. HomeExpertly is not a licensed lender, mortgage servicer, financial advisor, or tax professional.