What is Refinance Calculator?
Free mortgage refinance calculator with break-even analysis, side-by-side amortization, lifetime interest comparison, and cash-out modeling. Runs in your browser — no signup, no data uploaded. Free to embed on your website.
Refinance Calc runs entirely in your browser using JavaScript (browser). Your data never leaves your device.
Free Refinance Calculator
Decide whether to refinance with real math, not a rule of thumb. Enter your current balance, rate, and years remaining, then your new rate, term, and closing costs — and instantly see your new monthly payment, exact break-even month, lifetime interest saved, and year-by-year cumulative cash flow. Models rate-and-term, cash-out, and rolled-closing-cost scenarios. Built on a full month-by-month amortization engine so the numbers are auditable, not approximated.
Your current loan
Find these numbers on your most recent mortgage statement.
What you still owe — not the original loan amount.
The annual rate on your existing mortgage.
Roughly how many years are left on your current loan.
Proposed new loan
The rate your lender is offering for the refinance.
Most refinances reset to a 30-year term, but choosing the same or shorter term often saves more lifetime interest.
Lender fees, title, appraisal, recording, etc. Typically 2–5% of the loan amount.
Monthly cash flow
−$291.45
You save $291.45 per month with the new loan.
Break-even
Feb 2028
That's 1 yr 9 mo from your first new payment.
Current P&I
$2,138.60
New P&I
$1,847.15
Heads up: the new term is longer than what's left on your current loan — you'll be making payments for more years total, even if each month is cheaper.
Monthly cash flow
−$291.45
You save $291.45 per month with the new loan.
Break-even
Feb 2028
That's 1 yr 9 mo from your first new payment.
Current P&I
$2,138.60
New P&I
$1,847.15
Heads up: the new term is longer than what's left on your current loan — you'll be making payments for more years total, even if each month is cheaper.
Cumulative savings — year by year
The moment cumulative savings turns from red to green is your break-even point.
| Year | Current paid | New paid | Saved | Cumulative |
|---|---|---|---|---|
| Year 12026 | $25,663 | $22,166 | +$3,497 | -$2,503 |
| Year 22027 | $25,663 | $22,166 | +$3,497 | +$995 |
| Year 32028 | $25,663 | $22,166 | +$3,497 | +$4,492 |
| Year 42029 | $25,663 | $22,166 | +$3,497 | +$7,990 |
| Year 52030 | $25,663 | $22,166 | +$3,497 | +$11,487 |
| Year 62031 | $25,663 | $22,166 | +$3,497 | +$14,984 |
| Year 72032 | $25,663 | $22,166 | +$3,497 | +$18,482 |
| Year 82033 | $25,663 | $22,166 | +$3,497 | +$21,979 |
| Year 92034 | $25,663 | $22,166 | +$3,497 | +$25,477 |
| Year 102035 | $25,663 | $22,166 | +$3,497 | +$28,974 |
| Year 112036 | $25,663 | $22,166 | +$3,497 | +$32,471 |
| Year 122037 | $25,663 | $22,166 | +$3,497 | +$35,969 |
| Year 132038 | $25,663 | $22,166 | +$3,497 | +$39,466 |
| Year 142039 | $25,663 | $22,166 | +$3,497 | +$42,964 |
| Year 152040 | $25,663 | $22,166 | +$3,497 | +$46,461 |
| Year 162041 | $25,663 | $22,166 | +$3,497 | +$49,958 |
| Year 172042 | $25,663 | $22,166 | +$3,497 | +$53,456 |
| Year 182043 | $25,663 | $22,166 | +$3,497 | +$56,953 |
| Year 192044 | $25,663 | $22,166 | +$3,497 | +$60,451 |
| Year 202045 | $25,663 | $22,166 | +$3,497 | +$63,948 |
| Year 212046 | $25,663 | $22,166 | +$3,497 | +$67,445 |
| Year 222047 | $25,663 | $22,166 | +$3,497 | +$70,943 |
| Year 232048 | $25,663 | $22,166 | +$3,497 | +$74,440 |
| Year 242049 | $25,663 | $22,166 | +$3,497 | +$77,938 |
| Year 252050 | $25,663 | $22,166 | +$3,497 | +$81,435 |
| Year 262051 | $25,663 | $22,166 | +$3,497 | +$84,932 |
| Year 272052 | $25,663 | $22,166 | +$3,497 | +$88,430 |
| Year 282053 | $25,663 | $22,166 | +$3,497 | +$91,927 |
| Year 292054 | $0 | $22,166 | -$22,166 | +$69,761 |
| Year 302055 | $0 | $22,166 | -$22,166 | +$47,596 |
Monthly savings
−$291.45
Break-even
Feb 2028
When to use this refinance calculator
Refinance decisions aren't a rule of thumb — the math swings dramatically with your specific balance, the rate gap, and how long you actually plan to stay. Use this calculator when you've been quoted a new rate by a lender or are watching rates drop and wondering if it's time to move. The most common scenarios it answers: “Should I refi from 7.5% to 6.25% with $6,000 in closing costs?”, “Does it still make sense if I'm resetting from 28 years remaining to a new 30-year term?”, and “What if I take $40,000 cash out for a kitchen remodel — is the higher payment worth it?”
Lenders run versions of this same calculation when they quote you a refi — but they have an incentive to emphasize the lower monthly payment and downplay the closing costs and term reset. Running the numbers yourself, with the exact break-even month and lifetime interest comparison in front of you, gives you a much clearer picture of whether the deal is genuinely good or just looks good on the surface. Every input is editable, so you can stress-test the scenario: what if you only stay 4 more years instead of 10? What if rates drop another 0.5% next year? What if the closing costs come in higher than quoted?
How the refinance math works
A refinance is fundamentally two amortization schedules compared month by month. The current loan's schedule continues forward if you keep paying it; the new loan's schedule begins fresh. The calculator runs both and stacks them.
The monthly payment formula
Each loan's monthly principal-and-interest payment comes from the standard amortization formula used by every U.S. lender and codified by the Consumer Financial Protection Bureau:
M = P × r × (1 + r)n ÷ ((1 + r)n − 1)
where P is the principal (your new loan amount: current balance + cash-out + any rolled closing costs), r is the monthly interest rate (annual rate ÷ 12), and n is the term in months. The current loan's payment is computed the same way using your remaining balance and remaining months.
Break-even — the most important number
Break-even month = closing costs ÷ monthly cash-flow savings. If closing costs are $6,000 and the new payment is $300/month lower than your current one, you break even in month 20 (6,000 ÷ 300 = 20). After that month, every dollar of monthly savings is genuine money in your pocket; before it, you're still earning back the cost of the refi itself. This is the same simple break-even methodology the Federal Reserve uses in its consumer refinance guide — it's the industry standard because it directly answers the question that actually matters: how long do I need to stay in this house for the refi to pay off?
The calculator goes one step further and shows the exact calendar month of break-even, so you can compare it against your real plans. If your job might transfer you in 18 months but break-even is 27, the refi is probably a wash. If you're staying for 10+ years and break-even is 24, you'll bank the savings for nearly 8 years.
The term-reset trap
Most refinances reset to a new 15, 20, or 30-year clock. That can dramatically change the lifetime-interest math even if the rate drops. Example: you're 5 years into a 30-year loan at 7%. You refi into a new 30-year at 6%. Your monthly payment is lower — but you've added 5 years of payments at the end. Even with the lower rate, you may pay more total interest over the new loan's full term than you would have paid by sticking with the original. The lifetime-interest line in the results panel calls this out so you don't fall into the trap. If you want the rate drop without the term reset, refinance into a 15- or 20-year instead — the monthly payment is higher, but the lifetime savings are usually substantial.
Cash-out vs rate-and-term
A rate-and-term refi swaps your old loan for a new one at a better rate and/or different term. A cash-out refi does the same but with a larger new principal, with the extra paid to you in cash at closing. The calculator handles both: cash-out simply increases the new loan amount by your withdrawal, which scales the new monthly payment proportionally. Cash-out interest is no longer tax-deductible unless the proceeds are used to substantially improve the home (per the 2017 Tax Cuts and Jobs Act). Use cash-out for high-return uses (home improvements that add value, paying off higher-rate debt) and avoid it for short-term spending — you're trading 30 years of mortgage interest for whatever you spend the cash on.
Refinancing at 6.5% vs 7.0% vs 7.5% — which makes sense?
Imagine you have a $300,000 balance with 28 years remaining at 7.5%, and you're offered a new 30-year loan with $6,000 in closing costs paid upfront. Here's how the break-even changes with the new rate:
| New rate | New monthly P&I | Monthly savings | Break-even | Worth it? |
|---|---|---|---|---|
| 6.25% | $1,847 | $291 | 21 months | Yes — clear |
| 6.50% | $1,896 | $242 | 25 months | Yes — solid |
| 7.00% | $1,996 | $143 | 42 months | Maybe — stay 4+ yr |
| 7.25% | $2,047 | $92 | 66 months | Probably not |
Values rounded to the nearest dollar. The wider the rate gap, the faster the break-even — but the answer always depends on how long you actually plan to stay.
Common refinance mistakes to avoid
- Looking only at the lower monthly payment. A 30-year reset can mean five extra years of payments. Always check the lifetime-interest line, not just the monthly.
- Ignoring how long you'll stay. If your break-even is 30 months but you might relocate in 24, the refi loses money even at a great rate.
- Believing “no closing cost” really means free. Those offers bake the costs into a higher rate. For short hold periods this can still come out ahead; for long holds you pay more in interest. Compare both scenarios explicitly.
- Refinancing too early after closing. Some loans have prepayment penalties in the first 3–5 years. Check your current loan's note before signing on the new one.
- Rolling closing costs without doing the math. Rolling them feels free, but adds 1–3% to total interest paid over the loan's life. If you have the cash and plan to stay long-term, paying upfront is usually the better deal.
- Cash-out for non-appreciating purchases. Funding a kitchen remodel that adds equity makes sense; funding a vacation or new car is trading 30 years of mortgage interest for whatever you bought. The math almost never works.
- Not getting at least 3 lender quotes. Rates and closing costs vary by 0.25–0.5% and several thousand dollars across lenders for the same borrower. Use this calculator with each quote, then negotiate.
Frequently Asked Questions
When does refinancing actually make sense?+
The simplest test is the break-even month. If you plan to stay in the home longer than the break-even point (closing costs ÷ monthly savings), you come out ahead. A common rule of thumb is that you need at least a 0.75–1.0% rate drop to make the math worthwhile after closing costs, but that depends on your loan size, how long you'll stay, and whether you're extending the term. This calculator shows the exact break-even month for your specific scenario, so you don't need rules of thumb.
What is the break-even point on a refinance?+
Break-even = closing costs ÷ monthly cash-flow savings. If closing costs are $6,000 and you save $300/month, you break even after 20 months. After that month, every dollar of monthly savings is genuine money in your pocket. The Federal Reserve's consumer refinance guide uses this same simple break-even, and it's the industry standard. This calculator computes it precisely and also shows the exact calendar month it lands on, so you can compare it to how long you actually plan to stay.
Should I roll the closing costs into the new loan?+
Rolling costs into the loan means you pay them via interest over the entire term — typically adding 1–3% to your total interest. Paying them upfront in cash means you actually keep the full monthly savings from day one and reach break-even faster (because the savings start higher). Roll them in if cash flow at closing matters more than total interest paid. Pay them out of pocket if you have the savings and plan to stay long-term. Toggle the roll-closing-costs option to compare both scenarios side by side.
How does a cash-out refinance work?+
A cash-out refi replaces your existing mortgage with a larger one and pays you the difference at closing. If you owe $200,000 on a home worth $400,000 and do a $250,000 cash-out refi, you walk away with $50,000 (minus closing costs) and a new $250,000 loan. The cash is taxed only as a loan, not income — but you're trading equity for liquidity. Use cash-out for high-return uses (home improvements that add value, paying off higher-rate debt) and avoid it for depreciating purchases or short-term spending.
Will refinancing reset my mortgage clock?+
Usually yes — most refinances reset to a new 15, 20, or 30-year term. If you're 8 years into a 30-year and refi to another 30-year, you'll be paying for a total of 38 years on the home. The "Lifetime interest" comparison in this calculator shows the true impact: even with a lower rate, extending the term can sometimes cost more interest overall. You can refi into a 15-year to avoid this — your monthly payment will be higher, but you'll pay off years earlier with much less total interest.
What closing costs should I expect on a refinance?+
Typical refinance closing costs run 2–5% of the new loan amount and include: lender origination fee (0–1%), appraisal ($400–$700), title insurance ($500–$2,000), title search and recording fees ($200–$500), credit report ($25–$75), and prepaid items (taxes and insurance escrow). On a $300,000 refi, expect $6,000–$15,000 in costs. Some lenders offer "no-closing-cost" refinances by rolling costs into a slightly higher rate — for short hold periods this can be a better deal; for long holds you pay more in interest.
How is the new monthly payment calculated?+
New monthly P&I uses the standard amortization formula: M = P × r × (1+r)^n ÷ ((1+r)^n − 1), where P is the new principal (your current balance + cash-out + rolled closing costs), r is the new monthly rate (annual rate ÷ 12), and n is the new term in months. The calculator runs a full month-by-month schedule so the totals are accurate to the cent — same methodology used by lender underwriting tools.
Is my financial data stored anywhere?+
No. Every calculation runs entirely in your browser using JavaScript. Your balance, rate, and personal financial details are never uploaded to any server, never stored, never tracked. You can use this calculator on sensitive transactions with full confidence — including sharing pre-filled scenarios via URL, since the parameters live only in the link itself.
You might also like
Browse all 6 Real Estate tools →Mortgage Calculator
Full PITI mortgage calculator with amortization schedule and PMI tracking
Loan Calculator
Auto, personal, student & home equity loan calculator with amortization schedule
Paycheck Calculator
Calculate your take-home pay after taxes instantly