Mortgage Refinance Calculator
Use our free Mortgage refinance Calculator to plan your loans & mortgages strategy. Get detailed breakdowns, charts, and actionable insights.
Formula
M = P × [r(1+r)^n] / [(1+r)^n – 1]; Break-Even = Closing Costs / Monthly Savings
Where M = Monthly Payment, P = Loan Balance, r = Monthly interest rate (annual rate / 12 / 100), n = Total number of payments (term in years x 12). The break-even point is calculated by dividing total closing costs by the monthly payment difference, showing how many months until refinancing pays for itself.
Worked Examples
Example 1: Rate Reduction Refinance
Problem: You owe $300,000 on your mortgage at 7.0% with 25 years remaining. A lender offers 5.5% for a new 30-year mortgage with $6,000 in closing costs. Should you refinance?
Solution: Current loan:\n Monthly payment = $300,000 at 7.0% for 25 years\n M = 300000 × [0.005833(1.005833)^300] / [(1.005833)^300 – 1]\n M = $2,120.17/month\n Total remaining cost = $2,120.17 × 300 = $636,051\n\nNew loan:\n Monthly payment = $300,000 at 5.5% for 30 years\n M = 300000 × [0.004583(1.004583)^360] / [(1.004583)^360 – 1]\n M = $1,703.37/month\n Total cost = $1,703.37 × 360 + $6,000 = $619,213\n\nSavings:\n Monthly savings = $2,120.17 - $1,703.37 = $416.80\n Total savings = $636,051 - $619,213 = $16,838\n Break-even = $6,000 ÷ $416.80 = 15 months
Result: Monthly savings: $416.80 | Total savings: $16,838 | Break-even: 15 months — Yes, refinance!
Example 2: Shorter Term Refinance
Problem: You owe $200,000 at 6.0% with 22 years remaining. You can refinance to a 15-year loan at 4.75% with $4,500 closing costs. Compare the options.
Solution: Current loan:\n Monthly payment at 6.0% for 22 years (264 months)\n M = $1,507.09/month\n Total remaining = $1,507.09 × 264 = $397,872\n\nNew 15-year loan:\n Monthly payment at 4.75% for 15 years (180 months)\n M = $1,553.98/month\n Total cost = $1,553.98 × 180 + $4,500 = $284,216\n\nComparison:\n Monthly increase = $46.89\n Total savings = $397,872 - $284,216 = $113,656\n Pay off 7 years sooner
Result: Pay $47 more/month but save $113,656 total and pay off 7 years earlier
Frequently Asked Questions
When does it make sense to refinance my mortgage?
Refinancing typically makes sense when you can lower your interest rate by at least 0.5% to 1%, though even smaller reductions can be worthwhile on large balances. The key metric is your break-even point: divide your total closing costs by your monthly savings to find how many months until refinancing pays for itself. If you plan to stay in your home longer than the break-even period, refinancing is generally beneficial. Other good reasons include switching from an adjustable-rate to a fixed-rate mortgage for payment stability, shortening your loan term to build equity faster, or eliminating private mortgage insurance (PMI). Always compare the total cost of the remaining current loan against the total cost of the new loan including closing costs.
Should I refinance into a shorter or longer term?
The choice between a shorter and longer term depends on your financial goals and cash flow needs. Refinancing from a 30-year to a 15-year mortgage typically offers a lower interest rate (often 0.5%-0.75% less) and dramatically reduces total interest paid, but increases monthly payments significantly. For instance, refinancing $250,000 from a 30-year at 6.5% to a 15-year at 5.5% raises payments from $1,580 to $2,043 but saves over $150,000 in total interest. Conversely, extending your term lowers monthly payments but increases total interest paid over the life of the loan. A middle approach is refinancing to a lower rate with the same or slightly longer term, then making voluntary extra payments toward principal when your budget allows, giving you flexibility.
Can I refinance with bad credit or low equity?
Refinancing with bad credit or low equity is more challenging but not impossible. For conventional loans, most lenders require a minimum credit score of 620 and at least 20% equity to avoid PMI, though some accept as low as 5% equity with PMI. FHA Streamline refinances are available to borrowers with existing FHA loans regardless of credit score or home value, requiring minimal documentation. VA Interest Rate Reduction Refinance Loans (IRRRLs) offer similar benefits for veterans. If your credit score is below 620, consider spending 6-12 months improving it before applying by paying down existing debt, correcting credit report errors, and making all payments on time. Each 20-point improvement in credit score can reduce your rate by 0.125%-0.25%, potentially saving tens of thousands over the loan term.
What credit score do I need for the best mortgage rates?
A FICO score of 760 or higher typically qualifies you for the lowest advertised mortgage rates. Dropping from 760 to 700 can cost you 0.25-0.50% more in interest — on a $400,000 30-year loan, that difference costs roughly $60-$120 more per month and over $25,000 in extra interest. Scores between 620-699 still qualify for conventional loans but at noticeably higher rates. Scores below 580 generally require FHA loans, which accept down payments as low as 3.5% but mandate mortgage insurance for the life of the loan. Before applying, pay down revolving balances to below 30% of credit limits — this alone can boost your score 20-40 points.
How do mortgage points work?
Mortgage discount points are prepaid interest you pay at closing to permanently reduce your loan's interest rate. One point costs 1% of the loan amount — on a $350,000 mortgage, one point costs $3,500 — and typically lowers your rate by 0.20-0.25%. To determine whether buying points makes sense, calculate your break-even period: divide the upfront cost by your monthly savings. For example, $3,500 paid to save $55/month breaks even in about 64 months (5.3 years). If you plan to stay in the home beyond that point, buying points saves money. If you may sell or refinance sooner, keep the cash. Points are tax-deductible in the year of purchase for a primary residence.
When should I consider refinancing my mortgage?
Refinancing makes financial sense when the long-term interest savings exceed the upfront costs. The standard threshold is a rate reduction of at least 0.5-0.75%, though the actual benefit depends on your loan balance and remaining term. Calculate your break-even: if refinancing costs $5,000 and saves $175/month, break-even is about 29 months. You should also consider refinancing to switch from an ARM to a fixed rate for payment certainty, to eliminate PMI if your equity has grown, or to shorten your term from 30 to 15 years to save tens of thousands in interest. Avoid resetting a 25-year-old mortgage back to a new 30-year loan — you may pay more total interest even at a lower rate.