The savings depend on three numbers: your new interest rate, how many months are left on your loan, and whether you extend the term

A refinance saves money on your monthly payment only if at least one of these is true: your new interest rate is lower than your old one, you stretch the loan over more months, or both. The math is straightforward once you know those three pieces. If your rate drops but you keep the same payoff date, your payment falls. If your rate stays the same but you refinance into a longer loan, your payment falls—but you pay more interest overall. If your rate rises, your payment rises unless you extend the term enough to offset it.

The actual dollar amount of your savings is not fixed. A 0.5% rate drop on a $200,000 mortgage with 20 years left saves roughly $50 to $70 per month. The same rate drop on a $400,000 mortgage saves roughly $100 to $140. On a car loan, the numbers are smaller because the loan is smaller. The only way to know your specific savings is to run the numbers with your new rate, new term, and remaining balance.

Key Takeaways

  • Your monthly payment drops when your new interest rate is lower than your old rate, assuming you keep the same payoff date.
  • Extending your loan term (refinancing a 15-year mortgage into a 30-year one, for example) lowers your monthly payment but increases the total interest you pay over the life of the loan.
  • Lenders provide a loan estimate that shows your new monthly payment before you commit, so you can compare it directly to your current payment.
  • The savings calculation changes if you have a variable-rate loan that is about to adjust—your new fixed rate may be higher than your current rate even if it is lower than what your rate would have become.

How a lower interest rate reduces your payment

When you refinance at a lower rate, more of each payment goes toward principal and less toward interest. Your lender calculates a new payment amount based on the remaining balance, the new rate, and the number of months left until payoff. If you refinance a $150,000 mortgage balance at 6% with 20 years left, your payment is roughly $955 per month. If you refinance that same balance at 5% with 20 years left, your payment drops to roughly $895 per month—a savings of about $60 per month.

The lower your new rate, the larger the savings. A drop from 6% to 4.5% saves more than a drop from 6% to 5.5%. But the savings also depend on how much you still owe. A $50,000 loan sees smaller dollar savings than a $300,000 loan at the same rate drop, because the interest is calculated on a smaller balance.

Why extending your loan term lowers your payment but costs more overall

Refinancing into a longer term spreads your remaining balance over more months, which lowers your monthly payment. If you refinance a $150,000 balance from a 15-year mortgage into a 30-year mortgage at the same 5% rate, your payment drops from roughly $1,190 per month to roughly $805 per month. That is a $385 monthly savings.

But you pay significantly more interest over the life of the loan. On a 15-year term, you pay roughly $64,000 in total interest. On a 30-year term, you pay roughly $139,000 in total interest. You save money each month but spend roughly $75,000 more in interest by the time the loan is paid off. This trade-off makes sense only if you need the lower monthly payment to manage your budget right now and you plan to stay in the home or keep the loan long enough to benefit from the lower payment.

The loan estimate shows your exact new payment before you commit

When you explore to refinance, the lender sends you a Loan Estimate within three business days. This document lists your new interest rate, new loan term, remaining balance, and most importantly, your new monthly payment. Compare this payment directly to what you are paying now. The difference is your monthly savings (or increase, if rates have risen).

The Loan Estimate also shows closing costs—fees the lender charges to process the refinance. These costs typically range from 2% to 5% of the loan amount, though they vary by lender and loan type. If your monthly savings are $100 but closing costs are $3,000, you break even after 30 months. If you plan to stay in the home or keep the loan for longer than that, the refinance makes financial sense. If you plan to move or pay off the loan sooner, it may not.

Variable-rate loans complicate the comparison

If you currently have an adjustable-rate mortgage or ARM, your rate is set to increase on a specific date. Your current payment may be artificially low because you are in a fixed introductory period. When comparing your current payment to a refinanced payment, you need to know what your ARM rate will become, not what it is today.

If your ARM is currently 3% but will adjust to 6% in six months, refinancing into a fixed 5% rate may look like a rate increase—but it is actually a savings compared to what your payment would have been. Ask your lender what your ARM rate will adjust to and when. Then compare that future payment to the refinanced payment, not your current payment.

Closing costs and break-even timing

Refinancing is not free. Closing costs typically include an origination fee, appraisal fee, title search, title insurance, and other lender and third-party charges. On a $200,000 loan, closing costs often range from $4,000 to $10,000, though some lenders offer no-cost refinances that roll the fees into your interest rate instead.

To find your break-even point, divide your closing costs by your monthly savings. If closing costs are $5,000 and you save $100 per month, you break even after 50 months (about 4 years). If you plan to stay in the home or keep the loan for longer than that, the refinance pays for itself. If you plan to move or pay off the loan sooner, the closing costs may outweigh the savings.

Some lenders advertise no-cost refinances, which means they do not charge you upfront fees. Instead, they charge a slightly higher interest rate to cover their costs. This can make sense if you plan to refinance again soon or if you cannot afford closing costs upfront. Compare the interest rate on a no-cost refinance to the rate on a standard refinance to see which one saves you more money over time.

How to calculate your savings yourself

If you want to estimate your savings before contacting a lender, you need three pieces of information: your remaining loan balance, your new interest rate, and your new loan term. You can find your remaining balance on your most recent loan statement. Your new interest rate comes from a lender quote or rate sheet. Your new term is your choice—most people refinance into the same term they had left, but you can choose a different one.

Use an online mortgage calculator or auto loan calculator and enter these three numbers. The calculator shows your new monthly payment. Subtract this from your current payment to find your monthly savings. Then divide your closing costs by this monthly savings to find your break-even point in months.

Keep in mind that this is an estimate. Your actual new payment may differ slightly depending on your exact closing costs, whether you are paying property taxes and insurance as part of your payment, and other loan-specific details. The Loan Estimate from your lender is the authoritative number.

Frequently Asked Questions

Can I refinance if my home value has dropped?

It depends on your loan type and how much equity you have. Conventional loans typically require at least 20% equity. If your home value dropped, you may not have enough equity to refinance. FHA loans have different rules and may allow refinancing with less equity. Contact your lender to find out whether you are may be able to access based on your current home value and remaining balance.

What if my credit score has dropped since I took out my original loan?

A lower credit score usually means a higher interest rate on your refinance. If your score dropped significantly, your new rate may be higher than your current rate, which means your payment would increase rather than decrease. Check your credit report for errors before explore, and ask the lender what rate you would may have access to for based on your current score.

How long does it take to refinance?

The process typically takes 30 to 45 days from process to closing. During this time, the lender orders an appraisal, verifies your income and employment, orders a title search, and prepares closing documents. Your monthly payment does not change until the refinance closes and the new loan funds.

Do I have to refinance into the same loan term?

No. You can refinance a 30-year mortgage into a 15-year mortgage, or vice versa. Refinancing into a shorter term increases your monthly payment but saves you interest overall. Refinancing into a longer term decreases your monthly payment but costs you more in interest. Choose the term that matches your financial goals.

What if I want to pay off my loan faster after refinancing?

You can make extra payments toward principal at any time without penalty on most loans. If you refinance into a 30-year term to lower your monthly payment but then pay extra each month, you can still pay off the loan in 15 years or less while keeping the flexibility of a lower required payment. Check your loan documents to confirm there is no prepayment penalty.