Home Loan Refinance Calculator
This calculator helps you compare the financial impact of refinancing your home loan and optionally switching to bi‑weekly payments. It estimates monthly and bi‑weekly payment amounts, total interest over the loan life, approximate net savings after refinance costs, and a simple break‑even period.
Results are estimates based on amortization formulas and the inputs you provide. Use the outputs to inform discussions with lenders; get exact figures from loan documents before deciding.
Estimate outcomes if you refinance at a new rate and term, and optionally make bi‑weekly payments. Compares remaining interest on the current loan to interest on the proposed loan and reports estimated net savings and break‑even.
Inputs
Advanced inputs
Bi‑weekly settings
Results
Current monthly payment
$1,389.58
Interest remaining on current loan
$166,874.36
New monthly payment (refinance)
$1,157.79
New bi‑weekly payment (refinance)
$534.12
Total interest if refinanced (monthly payments)
$169,804.03
Total interest if refinanced (bi‑weekly payments)
$169,614.64
Estimated interest savings (monthly)
-$2,929.67
Estimated interest savings (bi‑weekly)
-$2,740.28
Approximate break‑even time (months)
12.9426
| Output | Value | Unit |
|---|---|---|
| Current monthly payment | $1,389.58 | USD |
| Interest remaining on current loan | $166,874.36 | USD |
| New monthly payment (refinance) | $1,157.79 | USD |
| New bi‑weekly payment (refinance) | $534.12 | USD |
| Total interest if refinanced (monthly payments) | $169,804.03 | USD |
| Total interest if refinanced (bi‑weekly payments) | $169,614.64 | USD |
| Estimated interest savings (monthly) | -$2,929.67 | USD |
| Estimated interest savings (bi‑weekly) | -$2,740.28 | USD |
| Approximate break‑even time (months) | 12.9426 | months |
Visualization
Methodology
We use standard amortization formulas to compute periodic payment amounts: for a period rate r and n periods, payment = P * r / (1 - (1+r)^-n). For bi‑weekly scenarios we convert the annual rate to a per‑period rate by dividing by 26. For monthly scenarios we divide by 12.
The tool compares estimated remaining interest on your current loan to interest under the proposed loan. Refinance costs are treated as upfront cash costs added to the total cash paid when computing net savings and approximate break‑even.
Data handling and security practices for this tool should follow NIST SP 800‑63 and NIST cybersecurity recommendations for web services. Testing and validation of numeric logic follows ISO/IEC and IEEE best practices for numerical software verification. This tool provides estimates only and should not be considered loan advice.
Worked examples
Example 1: Current balance $250,000, current rate 4.5%, 25 years remaining. Refinance to 3.75% for 30 years with $3,000 costs. The tool shows new monthly payment, total interest over the new term, and estimated interest savings compared to keeping the current loan.
Example 2: Same balance and rate, choose to make bi‑weekly payments (26 per year). The tool computes the bi‑weekly payment and estimates interest reduction vs monthly payments from extra effective payments.
Further resources
Expert Q&A
Are the numbers exact loan quotes?
No. This calculator uses standard amortization formulas to provide estimates. Actual lender quotes may differ due to rounding, how fees are financed, prepayment penalties, escrow changes, or different day‑count conventions.
How does bi‑weekly payment reduce interest?
Making 26 bi‑weekly payments of half your monthly payment results in 13 full monthly equivalents per year instead of 12, which accelerates principal reduction and lowers total interest. Exact savings vary by schedule and whether your lender applies payments immediately to principal.
What are the main accuracy caveats?
This tool assumes fixed rates and regular payments, no prepayment penalties, no changes to escrow, and that refinance costs are paid up front. Rounding, lender processing times, and how extra payments are applied can change results. Validate with lender figures.
What standards and practices inform this tool?
Numeric methods and software validation follow ISO/IEC and IEEE guidance for numerical computation testing. Data handling guidance cites NIST recommendations. For workplace safety of operations, OSHA standards apply to staff procedures but do not affect calculations.
Sources & citations
- NIST — Digital Identity Guidelines and cybersecurity recommendations — https://www.nist.gov
- ISO — Standards for software quality and numerical computing best practices — https://www.iso.org
- IEEE — Recommendations for verification and validation of numerical software — https://www.ieee.org
- OSHA — General workplace safety guidance — https://www.osha.gov