Mortgage Refinance Calculator
See if refinancing saves money - monthly payment drop, break-even point, and net savings after closing costs.
🔄 What is a Mortgage Refinance Calculator?
A mortgage refinance calculator helps homeowners determine whether replacing their existing mortgage with a new loan at a different rate or term will save money - and by exactly how much. Refinancing sounds simple, but the true benefit depends on three factors: the monthly payment reduction, the closing costs you must pay upfront, and how long you plan to stay in the home. Getting any of these wrong can turn a seemingly attractive refinance into a money-losing decision.
This calculator handles the full refinance analysis in one place. Enter your current remaining balance, existing rate, and remaining term, then compare against a new rate and term from your lender. Add estimated closing costs and the tool instantly shows your new monthly payment, your monthly savings, the exact break-even period (months until savings exceed closing costs), the total interest saved over the life of the new loan, and a net savings figure after accounting for what you paid to refinance.
Common refinance scenarios include: dropping from a 7% to a 6% rate to lower monthly payments; refinancing from a 30-year to a 15-year term to pay off the home faster and save massively on interest; or refinancing out of an adjustable-rate mortgage (ARM) into a fixed rate for payment stability. Each scenario has a different math profile - a rate-and-term refinance focused on monthly savings has different break-even dynamics than shortening your term to save on total interest even though monthly payments rise.
Two critical factors that simple "1% rule" estimates ignore: the term reset problem and closing cost drag. If you are 10 years into a 30-year mortgage and refinance into a new 30-year, you extend your payoff date by 10 years, which can mean paying more total interest despite a lower rate. And closing costs of 2%–5% of the loan balance can take 2–4 years to recover in monthly savings - if you sell or refinance again before reaching that break-even point, you've lost money. This calculator makes both of these dynamics transparent and quantifiable.
📐 Formula
M = P × r × (1+r)n ÷ ((1+r)n − 1)
M = monthly principal & interest payment
P = remaining loan balance (current or refinanced principal)
r = monthly interest rate = annual rate ÷ 12 ÷ 100
n = total remaining payments = term in years × 12
Monthly Savings = current payment − new payment
Break-Even (months) = closing costs ÷ monthly savings
Total Interest Saved = (current payment × current n − P) − (new payment × new n − P)
Net Savings = total interest saved − closing costs
Example: $250,000 balance, 7.5% → 6.0%, 25 yrs → 30 yrs: current payment $1,853; new payment $1,499; monthly savings $354; break-even on $5,000 costs = 15 months
📖 How to Use This Calculator
Steps to Analyze Your Refinance Decision
1
Enter your current loan balance - Use the remaining principal balance (what you currently owe), not the original loan amount. Check your latest mortgage statement for this figure.
2
Enter current rate and remaining term - Input your existing interest rate and how many years remain. If you are 8 years into a 30-year mortgage, enter 22 years remaining - this determines what your current payments will be over the remaining life of the loan.
3
Enter the new rate and new term - Input the refinance interest rate and term your lender has quoted. Try 15-year and 30-year versions to see the payment and total interest trade-off.
4
Add estimated closing costs - Enter your expected refinance closing costs. Ask your lender for a Loan Estimate document, which itemizes all fees. If you don't have a quote yet, use 2%–3% of your loan balance as a starting estimate.
5
Review break-even and net savings - Click Calculate to see your monthly savings, break-even period, and net savings after closing costs. If the break-even period is shorter than how long you plan to stay, refinancing makes financial sense.
💡 Example Calculations
Example 1 — Rate Drop Refinance, Same Term
$250,000 balance | 7.5% → 6.0% | 25 years remaining → new 30-year | $5,000 closing costs
1
Current payment: r = 7.5/12/100 = 0.00625; n = 300. M = $250,000 × 0.00625 × (1.00625)^300 ÷ ((1.00625)^300 − 1) = $1,853/month.
2
New payment at 6%/30-yr: r = 0.005; n = 360. M = $250,000 × 0.005 × (1.005)^360 ÷ ((1.005)^360 − 1) = $1,499/month.
3
Monthly savings = $1,853 − $1,499 = $354/month. Break-even = $5,000 ÷ $354 = 15 months.
4
Current total interest (25 yr) = $1,853 × 300 − $250,000 = $305,900. New total interest (30 yr) = $1,499 × 360 − $250,000 = $289,640. Interest saved = $16,260. Net savings = $16,260 − $5,000 = $11,260.
Monthly savings: $354 | Break-even: 15 months | Net savings: $11,260
Try this example →Example 2 — Term Shortening Refinance (30→15 Year)
$300,000 balance | 7.0% → 6.25% | 20 years remaining → new 15-year | $7,500 closing costs
1
Current payment at 7%/20-yr: r = 0.005833; n = 240. M = $300,000 × 0.005833 × (1.005833)^240 ÷ ((1.005833)^240 − 1) = $2,326/month.
2
New payment at 6.25%/15-yr: r = 0.005208; n = 180. M = $300,000 × 0.005208 × (1.005208)^180 ÷ ((1.005208)^180 − 1) = $2,572/month. Payment rises by $246/month, but term shortens 5 years.
3
Current total interest (20 yr) = $2,326 × 240 − $300,000 = $258,240. New total interest (15 yr) = $2,572 × 180 − $300,000 = $162,960. Interest saved = $95,280.
4
Net savings = $95,280 − $7,500 = $87,780. Higher monthly payment, but massive lifetime savings if you can sustain the cost.
Monthly payment rises $246 | Total interest saved: $95,280 | Net savings: $87,780
Try this example →Example 3 — Small Rate Drop, High Closing Costs (Borderline Case)
$180,000 balance | 6.75% → 6.25% | 22 years remaining → new 22-year | $6,000 closing costs
1
Current payment at 6.75%/22-yr: r = 0.005625; n = 264. M = $180,000 × 0.005625 × (1.005625)^264 ÷ ((1.005625)^264 − 1) = $1,372/month.
2
New payment at 6.25%/22-yr: r = 0.005208; n = 264. M = $180,000 × 0.005208 × (1.005208)^264 ÷ ((1.005208)^264 − 1) = $1,320/month. Monthly savings = $52.
3
Break-even = $6,000 ÷ $52 = 115 months (9.6 years). If you sell within 9 years, this refinance costs you money - you'll pay $6,000 in closing costs and never recover it in savings.
Monthly savings: $52 | Break-even: 9.6 years - only worthwhile if staying 10+ more years
Try this example →❓ Frequently Asked Questions
How do I know if refinancing my mortgage is worth it?
The core test: divide your total closing costs by your monthly payment reduction to get the break-even period. If you plan to stay in the home longer than that break-even period, refinancing saves money. A break-even under 24–36 months is generally considered favorable. This calculator shows you the exact break-even period and net lifetime savings so you can make a data-driven decision.
What is the break-even point in a mortgage refinance?
The break-even point is the number of months it takes for your cumulative monthly payment savings to equal your total closing costs. For example, if you save $200/month and paid $4,800 in closing costs, your break-even is 24 months. After that point, every month you stay in the home adds to your net savings. If you sell or refinance again before break-even, you've lost money on the transaction.
Does refinancing reset my 30-year mortgage clock?
Yes - refinancing into a new 30-year mortgage resets your amortization to 30 years, regardless of how long you've been in your current loan. If you are 12 years into a 30-year mortgage (18 years remaining) and refinance to a new 30-year, you now owe payments for 30 more years instead of 18. Even with a lower rate, you may pay significantly more total interest. Consider a 15- or 20-year refinance to avoid extending your payoff date.
How much do closing costs typically cost when refinancing?
Refinance closing costs typically run 2%–5% of the loan amount. On a $250,000 loan, that's $5,000–$12,500. Key components include the lender origination fee (0.5%–1%), home appraisal ($400–$700), title search and title insurance (0.5%–1%), recording fees, and prepaid interest. Some fees are negotiable. Always request a Loan Estimate from your lender, which itemizes every fee and is legally required within 3 business days of application.
What is a no-closing-cost refinance and is it worth it?
A no-closing-cost refinance eliminates upfront fees by either rolling them into your loan balance or accepting a slightly higher interest rate (typically 0.25%–0.5% higher). This is worth it if your break-even period would otherwise be 3+ years or if you plan to move or refinance again soon. If you plan to stay long-term, paying closing costs upfront and securing the lowest rate typically saves more money. This calculator lets you model both scenarios by setting closing costs to $0.
Should I refinance from a 30-year to a 15-year mortgage?
Refinancing to a 15-year mortgage typically saves 50–60% in total interest compared to continuing a 30-year loan, even accounting for closing costs. The monthly payment is higher - usually 25%–40% more - but the loan pays off in half the time and builds equity far faster. This strategy is best when the 15-year payment stays comfortably under 28% of your gross monthly income and you have stable employment. Use this calculator with a 15-year new term to see your specific numbers.
When is refinancing a bad idea?
Refinancing is likely a poor decision when: your break-even period exceeds how long you plan to stay in the home; your new rate is only marginally lower (0.25% or less) and closing costs are significant; you are far into your mortgage and refinancing to a longer term dramatically increases total interest; your credit score has dropped since your original mortgage, leading to a worse rate; or you are close to retirement and a new 30-year term creates income-stream risk. Always model the full numbers before deciding.
Can I refinance to eliminate PMI?
Yes. If your home has appreciated since purchase and your new loan balance represents 80% or less of your home's current appraised value, you can refinance without PMI - even if your original loan required it. For example, if you bought at $300,000 with 10% down and your home is now worth $380,000, your $250,000 balance is only 65.8% LTV and PMI can be eliminated. Eliminating PMI (often $100–$300/month) significantly improves the break-even math of any refinance.
How does credit score affect my refinance rate?
Your credit score is one of the most significant factors determining your refinance rate. Borrowers with scores above 760 typically qualify for the best (lowest) rates; each tier below that - 740, 720, 700, 680 - typically adds 0.125%–0.375% to your rate. A score below 620 may disqualify you from conventional refinancing entirely. Check your credit report before applying, dispute any errors, and avoid opening new credit accounts in the 3–6 months before refinancing.
How many times can I refinance my mortgage?
There is no legal limit on how many times you can refinance. However, practical limits exist: each refinance triggers new closing costs that must be recovered through savings before the next potential refinance. Some lenders impose a 6- to 12-month seasoning requirement before refinancing again. Serial refinancing can also extend your payoff date repeatedly if you keep resetting to 30-year terms. A disciplined approach: only refinance when break-even is under 3 years and you do not restart a full 30-year clock.
What is cash-out refinancing and how does it differ?
A cash-out refinance replaces your existing mortgage with a new, larger loan and gives you the difference in cash. For example, if you owe $200,000 on a home worth $400,000, you could refinance into a $280,000 loan and receive $80,000 cash (minus closing costs) to use for home improvements, debt payoff, or other purposes. The trade-off: your new loan balance is higher, monthly payments increase, and you are borrowing against your home equity. This calculator models rate-and-term refinances - for cash-out analysis, enter the new higher loan amount as the balance.