Mortgage Refinancing Estimate Calculator

Get 8 estimates in seconds: new monthly payment, monthly savings, current vs. new total interest, break-even, 5-year, 10-year, and lifetime net savings after closing costs.

Quick Answer

A refinancing estimate from this calculator gives you 8 numbers: new monthly payment, monthly savings, current and new total interest, interest saved, break-even months, 5-year net savings, and lifetime net savings after closing costs. Enter your balance, current rate, remaining term, new rate, new term, and estimated closing costs — the CFPB Loan Estimate from your lender has exact closing costs. Freddie Mac's PMMS tracks current average 30-year rates weekly.

Mortgage Refinancing Estimate Calculator

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Current Loan
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yrs
New Loan
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yrs
$
Monthly Payment Savings
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Current Payment
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New Payment
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Total Interest (Full Term)
Current loan interest —
New loan interest —
Interest difference —
Net Savings After Closing Costs
Closing costs —
Break-even point —
5-year net savings —
10-year net savings —
Lifetime net savings —

ℹ RefinanceUSA is not a lender. Results are estimates for comparison — actual loan terms vary by lender and credit profile. How we calculate

Monthly Savings vs. Total Interest Savings

Refinancing produces two distinct types of savings that don't always move in the same direction:

  • Monthly savings — the immediate cash flow improvement: how much less you pay each month after refinancing.
  • Total interest savings — the reduction in cumulative interest paid over the full lives of both loans.

These can diverge significantly when you change your loan term. Refinancing from 20 years remaining into a new 30-year term lowers your monthly payment but restarts a longer amortization clock — you may pay less each month but more in total interest, even at a lower rate.

When Both Move in the Same Direction

The ideal refinance cuts both monthly payment and total interest. This happens when you get a significantly lower rate and keep a similar term, or shorten the term enough that faster principal paydown outweighs a higher monthly payment.

When They Diverge

Extending your term while lowering your rate reduces monthly payments but may increase total interest. The calculator flags this — you'll see a positive monthly savings alongside a negative interest difference. Use the 5-year and 10-year net savings rows to gauge how long you'd need to stay for the monthly savings to outweigh the total interest penalty.

The Savings Formula

Here's the exact math behind each result in the calculator:

Monthly Savings = Current P&I − New P&I

P&I uses the standard amortization formula: Balance × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where r = monthly rate and n = term in months.

Total Interest (current) = (Current Payment × Remaining Months) − Balance
Total Interest (new) = (New Payment × New Term Months) − Balance
Interest Saved = Total Interest (current) − Total Interest (new)
Net Lifetime Savings = Interest Saved − Closing Costs
Break-Even = Closing Costs ÷ Monthly Savings

The 5-year and 10-year rows use (Monthly Savings × months) − Closing Costs — a cash-flow snapshot of where you stand at that point in time, regardless of when either loan ends.

How Loan Term Affects Total Savings

The choice of new term has a dramatic effect on total savings. Here's a comparison for a $320,000 balance refinancing from 7.25% with 28 years remaining:

New Term New Rate New Payment Monthly Δ Total Interest Interest Saved
30 yrs6.50%~$2,023/mo−$203/mo~$408K~$19K
25 yrs6.50%~$2,162/mo−$64/mo~$329K~$98K
20 yrs6.50%~$2,393/mo+$167/mo~$254K~$173K
15 yrs6.25%~$2,747/mo+$521/mo~$174K~$253K

The 15-year loan saves $253K in total interest — but costs an extra $521/mo. The 30-year refinance saves only $19K total but reduces monthly cash needs by $203. The right choice depends on your cash flow, how long you'll stay, and your financial goals.

Net Savings After Closing Costs

The break-even point is where cumulative monthly savings cover your upfront closing costs. Until that month, you are net-negative on the refinance.

Example: $6,000 closing costs at $200/month savings → break-even in 30 months. After 5 years: ($200 × 60) − $6,000 = $6,000 net. After 10 years: ($200 × 120) − $6,000 = $18,000 net.

No-Closing-Cost Refinances

Some lenders roll fees into the loan balance or accept a slightly higher rate in exchange for zero upfront costs. Set closing costs to $0 in the calculator — break-even is immediate, but your monthly savings will be smaller since the higher rate or balance offsets the fee waiver.

How Long Will You Stay?

The break-even is the floor. Most financial advisors target a break-even under 36 months as a baseline for a worthwhile refinance. If you plan to stay 5–10 years past break-even, the monthly savings compound into substantial lifetime gains.

Monthly Savings Reference Table — by Loan Size and Rate Drop

The table below shows approximate monthly P&I savings at different loan balances and rate reductions, starting from a 7.25% base rate on a 30-year loan. Monthly savings scale proportionally with loan size — so a $400K loan always saves exactly twice as much as a $200K loan at the same rate drop.

Rate Drop $200K $300K $400K $500K
0.50%$67/mo$100/mo$133/mo$166/mo
0.75%$99/mo$149/mo$199/mo$249/mo
1.00%$133/mo$200/mo$266/mo$333/mo
1.25%$165/mo$248/mo$330/mo$413/mo
1.50%$197/mo$295/mo$393/mo$492/mo

Based on 7.25% starting rate, 30-year term. Add $0.33/month per $100K for each additional 0.25% starting rate.

3 Worked Scenarios: Savings in Practice

Scenario A — Modest $180,000 balance, 0.75% rate drop

Small loan: does it still make sense?

Loan balance$180,000
Rate change7.25% → 6.50%
Monthly savings$89/mo
Closing costs (2%)$3,600
Break-even40 months
5-year net savings+$1,740
10-year net savings+$7,080

On small balances, monthly savings are modest in dollar terms — but break-even is still achievable. The key variable is closing costs: if a lender offers 1% origination on a $180K loan, the savings case improves significantly.

Scenario B — $350,000 balance, 1.0% rate drop

Typical mid-market refinance

Loan balance$350,000
Rate change7.25% → 6.25%
Monthly savings$233/mo
Closing costs (2%)$7,000
Break-even30 months
5-year net savings+$6,980
10-year net savings+$20,960

This is the sweet spot for most homeowners — a 1.0% rate drop on a mid-sized loan produces a compelling break-even inside 3 years with nearly $21,000 in cumulative savings over a decade.

Scenario C — $600,000 balance, 0.50% rate drop

High balance — smaller drop still adds up fast

Loan balance$600,000
Rate change7.25% → 6.75%
Monthly savings$200/mo
Closing costs (2%)$12,000
Break-even60 months
5-year net savings$0 (at break-even)
10-year net savings+$12,000

A 0.5% drop on a $600K loan saves $200/month — the same dollar amount as a 1.0% drop on $300K. But the higher closing costs push break-even to 5 years. This refinance only makes financial sense for a long-term hold. If you can negotiate closing costs to 1.5%, break-even drops to ~45 months.

12 Frequently Asked Questions

How do I get a refinancing estimate?
Enter your current loan balance, current interest rate, remaining term, new rate, new term, and estimated closing costs. The calculator returns 8 numbers instantly: new monthly payment, monthly savings, current total interest, new total interest, interest saved, break-even months, 5-year net savings, and lifetime net savings. For exact closing costs, request a CFPB Loan Estimate from your lender — it must be provided within 3 business days of application.
How do I calculate my refinance savings?
Monthly savings = current monthly payment minus new monthly payment. Total interest savings = total interest on the current loan minus total interest on the new loan. Net savings = total interest savings minus closing costs. Break-even = closing costs divided by monthly savings. This calculator runs all four calculations simultaneously as you type.
Does a lower rate always mean total savings?
Not if you extend your term. Refinancing from 20 years remaining into a new 30-year loan at a lower rate lowers monthly payments but adds a decade of additional payments. At some rate spreads, the extra years of interest outweigh the rate reduction. The total interest rows in the calculator tell you exactly which way your specific scenario goes — look for a positive "Interest saved" row to confirm the refinance wins on total cost.
How accurate is this refinancing estimate?
The P&I (principal and interest) calculation is mathematically exact given your inputs. In practice, your actual savings may vary due to: closing costs that differ from your estimate, the rate you qualify for based on credit score and LTV, and escrow components (taxes, insurance) not included here. Use this calculator to compare scenarios and understand relative savings; get a formal Loan Estimate from 3+ lenders for exact figures. Freddie Mac's PMMS survey tracks average weekly rates if you need a market baseline.
What closing costs should I expect when refinancing?
Typical refinance closing costs run 1.5–3% of the loan balance. Common fees include origination (0.5–1%), appraisal ($400–$700), title insurance ($500–$1,500), and recording fees ($50–$200). On a $320,000 balance, expect $4,800–$9,600. The CFPB Loan Estimate form itemizes every fee — compare it across lenders before entering a number into this calculator. The Closing Disclosure (provided 3 days before closing) confirms final costs.
How long do I need to stay to benefit from refinancing?
At minimum, through the break-even point. If closing costs are $6,000 and monthly savings are $200, break-even is 30 months. If you sell or refinance again before then, you'll have paid closing costs without recovering them. Most advisors recommend targeting a break-even under 36 months. The 5-year net savings row shows total gain if you stay exactly 5 years — a useful planning anchor.
How does refinancing affect my total loan payoff date?
If you refinance into a new 30-year loan after already paying for 5 years, your payoff date resets from 25 years out to 30 years — adding 5 years of debt. This calculator's "Total interest — new loan" field makes the trade-off visible: even with a lower rate, extending the term can increase total interest paid. To avoid the payoff-date reset, consider refinancing into a 20- or 25-year loan rather than defaulting to 30 years — enter both scenarios to compare the total interest difference.
Can I refinance an FHA loan to reduce my payments?
Yes. FHA loans can be refinanced via FHA Streamline (no appraisal, must reduce payment by at least 5% including FHA MIP) or via conventional refinance (if you have 20%+ equity, eliminates FHA mortgage insurance premium entirely — saving an additional $100–$250/month). Use the FHA Refinance Calculator to see the MIP impact on your total monthly savings alongside the rate savings.
Can VA loan holders get a refinancing estimate?
Yes. VA IRRRL refinances require a minimum 0.5% rate reduction for fixed-to-fixed refinances and no appraisal. VA refinances close faster (often 14–21 days) and cost $2,000–$4,000 less in closing costs than conventional refinances, which improves the break-even calculation significantly. Use this calculator for the payment estimate, then the VA Refinance Calculator for VA-specific fee structures including the funding fee.
Should I pay mortgage points to get a lower rate?
Paying mortgage points lowers your rate by about 0.25% per point (1 point = 1% of balance). On $300,000, 1 point ($3,000) saves ~$50/month — a 60-month break-even. Points make sense if you plan to stay past break-even. Enter the lower rate and add the point cost to closing costs in this calculator to see the net effect on your savings estimate. The Mortgage Points Calculator compares point scenarios side by side.
Does PMI affect my refinancing estimate?
Yes — if refinancing eliminates PMI by bringing your LTV below 80% (based on current appraised value), add PMI savings to your monthly savings total. PMI typically costs $50–$250/month. Combined with rate savings, total monthly improvement can reach $300–$500/month, dramatically shortening break-even. The PMI Removal Calculator shows when your current loan crosses 80% LTV naturally, which helps you decide whether to act now or wait.
Can I make bi-weekly payments on the new loan to save more?
Yes. Bi-weekly payments — half your monthly payment every two weeks — produce 26 half-payments per year, equivalent to one extra monthly payment annually. On a $300,000 30-year loan at 6.5%, bi-weekly payments shorten the loan by approximately 4–5 years and save $30,000–$40,000 in additional interest beyond the rate-reduction savings. Confirm with your servicer that they accept bi-weekly payments and credit the extra directly to principal — some require a formal plan or charge a small fee.

Net Savings When You Roll Closing Costs Into the Loan

Many refinancing homeowners roll closing costs into the new loan balance rather than paying them out of pocket. This is called "no-cash-close" refinancing and is available whenever you have sufficient equity. It eliminates the upfront cash requirement — but it has a meaningful impact on your actual net savings and break-even timeline.

How Rolling Costs Affects Your Numbers

When you finance closing costs, you're borrowing more money at the new rate instead of paying a lump sum today. This means:

  • Your new loan balance is higher than your payoff balance (by the amount of costs financed)
  • Your monthly payment is slightly higher than if you had paid costs upfront
  • Your true "break-even" is essentially zero months — but your net savings over time are smaller

Worked Example: $6,000 Costs — Pay Upfront vs. Roll In

Pay Costs UpfrontRoll Costs Into Loan
New loan balance$300,000$306,000
New rate (30-yr)6.50%6.50%
Monthly P&I$1,896$1,934
Upfront out-of-pocket$6,000$0
Month 1 net vs. old payment−$220 (savings)−$182 (savings)
5-year net (savings − costs)$13,200 − $6,000 = $7,200$10,920 − $0 = $10,920
Lifetime interest cost added$0~$7,600 extra on $6K financed

Rolling costs in produces better 5-year net savings if you don't have the cash — but the $6,000 you financed accrues ~$7,600 in total interest over 30 years. If you have cash available, paying upfront is the mathematical winner for long-hold scenarios. If you plan to sell or refinance again within 5–7 years, the rolled-in approach wins on net cash flow.

To model the rolled-in scenario in this calculator: add the closing costs to your current loan balance and enter that as the "New Loan Balance." The difference vs. your actual payoff balance represents the financed costs.

Three Ways to Deploy Your Monthly Savings

This calculator shows you what you save. How you use that savings is the second decision — and it has a larger long-term impact than most borrowers realize. Here are three strategies, with the math on each.

Strategy 1: Prepay Principal Every Month

Apply your monthly savings back into an extra principal payment. On a $300,000 loan at 6.5%, a $175/month extra payment shortens the loan by approximately 6.5 years and saves ~$58,000 in interest. This strategy is risk-free and guaranteed — your savings are entirely from interest elimination, not market returns. Best for: borrowers who value debt elimination and certainty over market exposure.

Strategy 2: Invest the Difference

$175/month invested in a diversified index fund at a long-run average of 7% annual return compounds to approximately $87,000 over 20 years. That significantly exceeds the $58,000 interest savings from prepayment. The tradeoff: market returns are not guaranteed, and the investment grows in parallel with your mortgage balance — you carry more debt while holding more assets. Best for: borrowers with stable income, high risk tolerance, and long investment horizons.

Strategy 3: Emergency Fund First, Then Invest

If your liquid reserves are below 3–6 months of expenses, using the savings to build an emergency fund first is often the highest-value step — it prevents expensive debt events (credit card balances from unexpected expenses) that would quickly erase the refinance benefit. Once the fund is funded, redirect savings to prepayment or investment. Best for: borrowers with thin reserves whose biggest financial risk isn't their mortgage rate.

The compound answer: For most borrowers, a combination of strategies delivers the best outcome: build 3-month reserves first, then split the remaining monthly savings between extra principal and index fund investment. Neither extreme (all prepayment or all investment) is optimal for most risk profiles and time horizons.

Related Guides

Ready to Compare Lender Offers?

The full RefinanceUSA calculator lets you enter multiple lender offers side by side and shows your exact payment, savings, and break-even for each — so you can pick the offer that actually saves you the most.

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Disclaimer: All calculations are estimates for informational purposes only. Results assume a fixed-rate loan with no extra payments and do not account for taxes, insurance, or PMI. Actual savings depend on your specific loan terms and lender fees. Consult a licensed mortgage professional before making any refinancing decision.

Sources & References