What is Refinance Calculator?
A refinance calculator helps you determine whether replacing your current mortgage with a new loan makes financial sense. By comparing your current monthly payment against a potential new payment, you can see exactly how much you would save each month, how long it takes to recover closing costs (the break-even point), and the total interest savings over the life of the loan.
Refinancing is one of the most powerful tools homeowners have to reduce their housing costs. Even a rate reduction of 0.5% can save hundreds of dollars per month on a typical mortgage. However, refinancing comes with closing costs that typically range from 2% to 6% of the loan amount. This calculator helps you cut through the noise and see the real numbers - so you can make an informed decision about whether refinancing is right for your situation.
The calculator also lets you specify how long you plan to stay in the home, which is the single most important factor in determining whether refinancing saves you money. If you sell before reaching the break-even point, you lose money on the refinance.
Three modes cover the three refinance decisions in one place: Compare mode for a straight rate-and-term swap, Cash-out mode for borrowing against equity, and Solve mode for finding the highest rate that still meets your break-even target.
When to Use This Calculator
- When a lender quotes you a lower rate and you need to know if the fees are worth it.
- Before choosing between rolling closing costs in and paying them upfront.
- When you are weighing a shorter term against the lower payment of a longer one.
- If you are considering a cash-out refinance and want the net effect on your equity.
- As rates move, to decide whether refinancing your existing loan beats waiting.
- When you plan to sell within a few years and need the break-even to fit inside that window.
Steps:
- Enter your current loan balance, interest rate, and remaining term in years.
- Enter the new interest rate and term you are considering.
- Enter the estimated closing costs for the refinance.
- Optionally, enter how many years you plan to stay in the home.
- Review your monthly savings, break-even point, and total interest savings.
- Use the mode tabs to analyze savings, break-even, or total cost comparison.
Formula
Monthly Payment = P × [r(1+r)^n] / [(1+r)^n - 1]
Where P = loan balance, r = monthly interest rate (annual rate ÷ 12), n = total number of payments
Monthly Savings = Current Payment - New Payment
Payment Break-Even Months = Closing Costs / Monthly Savings
True Break-Even = first month m where (C_cur - C_new) - Closing Costs + (B_cur - B_new) >= 0
Total Interest Savings = (Current Total Remaining Interest) - (New Total Interest + Closing Costs)
Net at Horizon = (Monthly Savings × Months You Stay) - Closing Costs + (Current Balance - New Balance)
Use Cases
- Evaluating whether to refinance your current mortgage
- Comparing different refinance offers from multiple lenders
- Deciding between a shorter term with higher payments vs. lower total interest
- Determining if paying discount points makes financial sense
- Planning how long you need to stay in your home to benefit from refinancing
- Checking whether a cash-out refinance leaves you ahead after the bigger balance
- Finding the highest new rate that still breaks even within your target months
- Comparing an upfront-cost refinance against rolling the fees into the loan
Key Benefits
- Get accurate refinance comparison results instantly
- Save time with automated break-even calculations
- Make informed decisions with clear savings data
- Free on any device no downloads
- See both the payment break-even and the amortization-aware break-even, not just the flattering one
- Compare three decisions in one tool: lower rate, shorter term, or cash out
Pro Tips
- Run the scenario twice: once with costs paid upfront and once rolled into the loan - the true APR tells you which is cheaper
- Set your real stay horizon; every net figure on this page depends on it
- Pull three Loan Estimates from different lenders and feed each one through Compare mode
- If the payment break-even is close to your planned move date, treat the refinance as a no-go
- Pair the amortization schedule with this analysis to watch how fast the new loan's balance falls below the old one
Common Mistakes to Avoid
- Judging a refinance only by the monthly payment and ignoring the longer amortization schedule
- Assuming payment break-even is the whole story when closing costs are rolled into the new balance
- Selling or refinancing again before the break-even month and turning the saving into a net loss
- Comparing the quoted rate instead of the true APR after origination, appraisal and title fees
- Choosing a 30-year term for the lower payment when the plan is to keep the loan only a few years
Key Terms Explained
- Break-even point:
- the month where the refinance has recovered its own costs. This calculator shows the payment-based month and the amortization-aware month, which differ whenever the term changes.
- True APR:
- the Regulation Z annual percentage rate computed after upfront finance charges, making offers with different fee structures comparable.
- Closing costs:
- origination, appraisal, title and recording fees due at settlement - typically 2% to 6% of the balance.
- Cash-out refinance:
- a new loan larger than your payoff balance, with the difference paid to you in cash, capped here at 75% of the current balance.
- Equity erosion:
- the principal your current schedule had already retired that the new, longer schedule rebuilds.
- Net at horizon:
- payment savings minus upfront costs plus the balance difference at your planned stay - the single number that decides the refinance.
- Discount point:
- prepaid interest at closing - 1% of the loan amount - that buys about 0.25% off the note rate.
- Amortization:
- the level-payment schedule that splits each payment into interest on the balance and principal reduction.
Related Concepts
- Mortgage Calculator: price the loan you have or the one you are considering before you commit to refinancing.
- Amortization Schedule Calculator: see the month-by-month split of principal and interest for both the old and the new loan.
- Home Affordability Calculator – How Much House: step back to the buying decision when a refinance is part of a larger move.
- HELOC Calculator: compare a second lien against the cash-out refinance route for tapping equity.
- Mortgage Points Calculator: buy the rate down instead of refinancing when you already like the loan.
- Loan Calculator: the same amortization engine for any loan, without the refinance-specific views.
Example
You have a $250,000 mortgage at 6.5% with 25 years left, so the payment is $1,688.02. A refinance at 5.5% for 30 years with $5,000 in closing costs drops it to $1,419.47 - $268.55 saved every month. On payments alone you break even at month 18.6, which rounds up to 19, but the longer term rebuilds $12,574.08 of principal the old loan had already paid down, so the amortization-aware break-even is month 25. Stay 10 years and the net advantage is $14,651.37: roughly $32,226 of payment savings minus the $5,000 in costs and the equity difference. Lifetime interest actually rises - the new loan pays $261,010.10 against the old loan's $256,405.37, a $4,604.73 increase before fees - so the win here is the decade of cash flow, not total interest.
Interpreting Your Results
Work left to right: the current-loan card takes the balance, rate and years left; the new-loan card takes the rate and term you are considering, plus closing costs and your planned stay. The preset chips load four complete scenarios - a gentle rate cut, a large drop, a shorter term, and a cash-out. The hero reports the headline figure for the mode, and the sub-stats break it into payment, break-even, true APR and equity cost. The break-even sub-stat is the payment-based month; the step-by-step solution below shows the amortization-aware month beside it, which is the one to trust whenever the term changes. Cash-out mode replaces the hero with the cash in hand; Solve mode asks for a target break-even and answers with the highest rate that still meets it. Every table and chart carries the same figures the hero reports, so any view works for a screenshot.