When Is Refinancing Worth It? Break-Even Math

Refinancing is worth it when what you save over the time you'll keep the new loan is more than what the refinance costs. The usual shortcut, closing costs divided by monthly savings, is a fine first check. But it can be badly wrong when the new loan restarts a 30-year clock or when New York's mortgage recording tax is part of the cost.

This guide shows the math with real numbers, the NYC costs that change the answer, and a quick decision tool.

The simple break-even, and why it misleads

The shortcut most lenders quote:

Break-even months = total refinance costs ÷ drop in monthly principal-and-interest payment

If closing costs are $9,000 and your payment falls $450 a month, you break even in 20 months. The flaw: a lower payment doesn't only come from a lower rate. It also comes from spreading what you owe over more years. The Consumer Financial Protection Bureau warns that refinancing into a new, longer term "could mean a lower monthly payment, but paying more money in total."

A fairer test adds one step. At any month, compare (payments you saved) minus (how much more you still owe on the new loan than you would on the old one). When that number passes your costs, you're truly ahead.

Worked example: a $450,000 balance in NYC

You owe $450,000 at 7.00% with 25 years left on a house. A lender offers 6.00%. Non-tax closing costs are $9,000. Because the new loan is under $500,000 and the property has fewer than seven units, your share of NYC mortgage recording tax without a CEMA is about 1.80%, or $8,100. Rates here are illustrative, not quotes.

Three things jump out:

1. The 30-year refi looks best on the simple test but costs more in total. It cuts the payment the most, yet you'd pay about $17,000 more interest over the life of the loan than if you kept the old one, because you've added five years.
2. The true break-even for the 30-year refi is 50 months, not 35. In the early years you pay down principal more slowly on a 30-year loan, so part of your "savings" is just debt you still owe.
3. Matching the remaining term is the honest comparison. The 25-year refi saves less each month but cuts lifetime interest by about $84,000 and truly breaks even sooner. The CFPB notes you can often pick a custom term, such as 22 years instead of 30.

Try your own numbers in the refinance break-even calculator, or compare payments below.

NYC costs that change the answer

Mortgage recording tax, and how a CEMA cuts it

New York taxes the recording of a mortgage, and in most cases a refinance is taxed again. In NYC the combined rate is 2.05% for loans under $500,000 and 2.175% for residential loans of $500,000 or more. On 1-6 unit property the lender pays 0.25% of that, leaving roughly 1.80% or 1.925% for you. On a $600,000 refinance that is about $11,550.

A Consolidation, Extension and Modification Agreement (CEMA) lets your new lender take an assignment of your old mortgage, so you pay tax only on new money. On a rate-and-term refinance with no cash out, that can wipe out most of the tax. CEMAs have their own legal fees, and not every lender offers them. Read CEMA loans in New York and check the numbers with the mortgage recording tax calculator.

Co-op refinances

Co-op share loans owe no mortgage recording tax, according to the Department of Finance, which lowers refinance costs. The catch is the building. A co-op loan is secured by your shares and proprietary lease, and the lender files a UCC financing statement. Lenders typically require a recognition agreement signed by the co-op (usually through the managing agent), and many buildings cap how much of an apartment's value can be financed. Ask the managing agent for the refinance requirements and fees before you apply. See co-op share loans vs mortgages.

Rate-and-term vs cash-out

A rate-and-term refinance replaces your loan to change the rate or term. A cash-out refinance borrows more than you owe and hands you the difference. Under Fannie Mae's rules for cash-out loans, at least one borrower must have been on title for six months, and a first mortgage being paid off must be at least 12 months old.

If you already have a low rate, cashing out means giving it up on your whole balance. A home equity line or loan may cost less. See HELOC vs home equity loan vs cash-out refinance and the cash-out refinance calculator. In NYC, the new money in a cash-out refinance is subject to recording tax even with a CEMA.

Should you refinance? Quick decision tool

Your refinance checklist, in order

1. 1

   Check for a prepayment penalty

   It is in your note and on your original Loan Estimate or Closing Disclosure. A penalty adds to your costs.
2. 2

   Know your remaining term and balance

   Your monthly statement shows both. You need them to compare like with like.
3. 3

   Collect three Loan Estimates

   Ask each lender whether it will do a CEMA. Compare total closing costs and points, not just the rate.
4. 4

   Run the true break-even

   Include recording tax, title, appraisal and attorney fees. Compare at the same remaining term.
5. 5

   Co-op? Call the managing agent first

   Confirm the building’s financing limit, recognition agreement process and fees.
6. 6

   Lock the rate once the math works

   See our guide to mortgage rate locks for how long to lock.

Related: mortgage rate locks, reading your Loan Estimate, and NYC mortgage recording tax.

General information, not financial advice. Your rate, costs and taxes depend on your loan, property and lender.