Mortgage Recast Calculator
A recast applies a lump sum to your principal and re-amortizes the loan, lowering your monthly payment while keeping the same rate and the same payoff date. Enter your balance and lump sum to see the new payment — and what the same money would do if you simply prepaid instead.
Recast versus refinance
They solve different problems and are often confused.
A refinance replaces your loan. New rate, new term, new closing costs — typically 2–5% of the balance, plus an appraisal and a full underwriting process. It is worth doing when rates have dropped meaningfully since you borrowed.
A recast keeps your loan exactly as it is. Same rate, same servicer, same remaining term. You hand over a lump sum, and the servicer recalculates the monthly payment against the smaller balance. The fee is usually $150–$500 and there is no credit check.
If you locked a 3% rate in 2021, refinancing today would be a disaster and recasting is the only way to convert cash into a lower payment. That is the situation this calculator is built for.
The comparison that actually decides it
Look at the last three outputs. If you pay the lump sum but do not recast — you keep sending the old, larger payment — the loan simply finishes earlier, and you save more interest than recasting does. Sometimes a lot more.
So the real question is not "does a recast save money." It is: do you want lower required payments, or do you want to be done sooner?
Lower required payments buy flexibility. If your income is variable, or a spouse is about to stop working, or you want the option to redirect cash into investments, that flexibility has real value. You can always choose to keep paying the old amount after a recast and get both.
Being done sooner saves more interest but locks the money away. Once it is in the house, getting it back means a cash-out refinance or a HELOC.
Before you count on this
Not all loans can be recast. FHA, VA, and USDA loans generally cannot. Most conventional loans can, but it is the servicer's policy, not a legal right — call and confirm before you commit the cash.
There is usually a minimum. Many servicers require $5,000–$10,000, or that the lump sum reduce the principal by at least 10%.
Your escrow does not change. The payment reduction shown here applies to principal and interest only. Property tax and insurance are collected separately and will keep moving with your assessment and premiums.
Frequently asked questions
Does a mortgage recast lower my interest rate?
No. The rate and the remaining term both stay exactly the same. Only the principal balance changes, and the monthly payment is recalculated against it. If you want a lower rate you need a refinance, which is a different and far more expensive process.
Is it better to recast or just make a lump-sum principal payment?
Prepaying without a recast saves more total interest, because you keep making the larger payment and the loan ends sooner. Recasting saves less interest but frees up monthly cash flow. This calculator shows both figures so you can see the size of the trade-off in your specific case.
How much does a mortgage recast cost?
Most servicers charge a flat $150–$500 administrative fee. There is no appraisal, no closing costs, and no credit check, which is what makes it dramatically cheaper than a refinance. The calculator shows how many months of payment savings it takes to cover the fee.
Which loans are eligible for recasting?
Most conventional loans are, but FHA, VA, and USDA loans generally are not. Jumbo loan policies vary by servicer. Eligibility is set by your servicer rather than by law, so confirm with them before committing the lump sum.
Can I keep paying my old payment amount after a recast?
Yes, and it is often the best of both worlds. The recast lowers what you are required to pay, so your downside is protected if income drops, while voluntarily continuing the old payment amount pays the loan off early anyway.