Mortgage Refinance Calculator

What This Refinance Calculator Does

This calculator computes your monthly savings from refinancing to a lower interest rate, the total closing costs of the refinance, and the break-even point — how many months until the monthly savings recover the upfront closing costs. It also shows the long-run interest savings (or cost) of extending or shortening your loan term.

The Break-Even Point

The break-even point is the most important number in a refinance decision. If closing costs are $5,000 and monthly savings are $250, break-even is 20 months. If you sell or refinance again before 20 months, the refinance cost you money. If you stay past 20 months, every month thereafter is net savings.

A refinance that makes sense for someone planning to stay 10 years might be wrong for someone planning to sell in 2 years — even at the same rate improvement and closing costs. Match the break-even to your realistic time horizon in the home.

When Refinancing Makes Sense

As a general rule, refinancing is worth considering when you can reduce your rate by at least 0.5%–0.75%, you plan to stay in the home past the break-even point, and you have at least 20% equity (to avoid PMI and qualify for the best rates). But the rule-of-thumb needs to be verified with actual numbers for your specific loan and rate environment.

Cash-Out Refinance

A cash-out refinance replaces your existing mortgage with a larger one and pays you the difference in cash. If you owe $200,000 on a $350,000 home and do a cash-out refinance to $270,000, you receive $70,000 in cash (minus fees), and now have a new $270,000 mortgage. Cash-out refinances are used for home improvements, debt consolidation, or major expenses. The cash is not taxable income but increases your mortgage balance and monthly payment.

Real-World Examples

Rate-and-Term Refinance

Current: $280,000 balance, 7.25% rate, 24 years remaining, $1,978/month (P&I). New: 6.5% rate, 30-year term, $1,770/month. Monthly savings: $208. Closing costs: $4,800. Break-even: 23 months. If staying 5+ more years, this refinance makes strong financial sense — $208/month for 36 months (after break-even, before sale) = $7,488 in savings.

Note: resetting from 24 remaining years to 30 years extends total interest paid. Run the total interest comparison — the lower rate may not save money on a total-interest basis if the term extends significantly.

Common Mistakes

Focusing only on monthly payment, not total interest

A refinance that lowers your monthly payment by resetting a 20-year loan back to 30 years at only a slightly lower rate can cost tens of thousands more in total interest. Always compare total cost, not just monthly payment.

Rolling closing costs into the loan without checking the math

Adding $6,000 in closing costs to your mortgage balance means you're paying interest on those closing costs for the life of the loan. At 6.5% over 30 years, $6,000 in rolled-in costs actually costs about $13,600 total.

Tips and Best Practices

• Shop at least 3–5 lenders — refinance rates and fees vary significantly between lenders. The lowest rate may not have the lowest fees.
• Compare APR, not just rate — APR incorporates fees into an annualized rate, making lender comparison more accurate than comparing interest rates alone.
• Consider a 15-year refinance — if you can absorb a higher monthly payment, a 15-year mortgage offers substantially lower rates and cuts total interest dramatically compared to a 30-year refinance.

Related Calculators

• Mortgage Calculator — model your new payment before applying.
• Closing Costs Calculator — estimate refinance transaction costs.
• Home Affordability Calculator — if considering moving instead of refinancing.

Frequently Asked Questions

How much equity do I need to refinance?

Most lenders require at least 5%–10% equity to refinance at all. To avoid PMI, you need 20%. To qualify for the best rates and terms, 20%+ equity is generally expected. If you have less than 20%, refinancing may still be worthwhile but factor in any PMI cost in the break-even calculation.

Does refinancing hurt my credit score?

A hard credit pull for a mortgage application typically reduces your score 5–10 points temporarily. Multiple lenders pulling your credit within a 14–45 day window are usually treated as a single inquiry for rate-shopping purposes. The score typically recovers within a few months.

Can I refinance if I'm underwater on my mortgage?

Traditional refinancing requires positive equity. However, the HARP program (now expired) and similar programs have occasionally been available for underwater borrowers. In most cases, underwater borrowers must either wait for equity to recover or explore loan modification programs with their servicer.

How often can I refinance?

There's no legal limit, but waiting periods may apply (typically 6 months for FHA and VA streamline refinances). Practically, each refinance resets the break-even clock — serial refinancing into marginally lower rates may not make economic sense once total closing costs are considered.

Key Takeaways

A refinance is a financial transaction with upfront costs and a payback period — treat it like any investment with a required return. The break-even timeline is the core decision variable: know it before you apply. Extend that break-even analysis to total interest saved or paid, not just monthly payment, to avoid the trap of lower monthly payments that cost more over the life of the loan. And shop multiple lenders — the rate and fee competition on refinances is significant and worth the time.