Fidamen

Mortgage Refinance Calculator with Bi-Weekly Payments

This tool compares your current mortgage schedule to a proposed refinance and offers a separate comparison of switching from monthly to bi-weekly payments. Enter your loan balance, interest rates, terms and the payment frequency (12 or 26 payments per year). Results show per-period payments, total interest over the remaining life, estimated interest savings and an approximate break-even for closing costs.

The calculator provides estimates only. Results depend on your inputs and assumptions (for example, whether closing costs are paid up front or financed). Use the output to inform decisions; confirm exact numbers with your lender and review loan documents carefully.

Updated Nov 2, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 1270f9065c0a • Reviewed by Fidamen Standards Committee

Compare total cost and payments for your current mortgage vs a proposed refinance using the payment frequency you specify for each loan.

Inputs

Results

Updates as you type

Current payment (per period)

-$3.54

Proposed payment (per period)

-$2.43

Total interest remaining (current)

-$301,062.50

Total interest (new loan)

-$300,875.00

Total interest savings

-$187.50

Approximate annual savings

-13.33 currency/year

Estimated break-even (months)

—

OutputValueUnit
Current payment (per period)-$3.54USD
Proposed payment (per period)-$2.43USD
Total interest remaining (current)-$301,062.50USD
Total interest (new loan)-$300,875.00USD
Total interest savings-$187.50USD
Approximate annual savings-13.33 currency/yearcurrency/year
Estimated break-even (months)—months
Primary result-$3.54

Visualization

Methodology

Periodic payment is calculated using the standard amortizing loan formula: payment = r * PV / (1 - (1+r)^-n) where r is the periodic rate and n is the number of remaining periods.

Total interest equals the sum of all scheduled payments minus the principal balance. Break-even estimates divide closing costs by the calculated annual cash-flow savings to approximate time to recover closing costs.

Bi-weekly vs monthly comparisons use 26 and 12 payments per year respectively and recompute payment and total interest for the same principal, rate and remaining term.

Key takeaways

Enter current loan details and proposed refinance terms. For frequency, enter 12 for monthly or 26 for bi-weekly payments in the payments-per-year fields.

The tool returns estimated per-period payments, total interest for each scenario, estimated annual savings, and an approximate break-even for closing costs.

F.A.Q.

Should I include closing costs in the new loan principal?

This calculator treats closing costs as a cash outlay (not financed). If you plan to finance closing costs into the loan, payments and total interest will change; consult your lender and re-enter the effective loan amount as the principal.

Why do bi-weekly payments sometimes save interest?

Bi-weekly schedules make 26 half-payments per year, which equals 13 monthly-sized payments—one extra monthly payment per year—reducing outstanding principal faster and lowering total interest over the loan life.

How accurate are the results?

Results are approximate and depend on input accuracy and assumptions. They do not account for irregular extra payments, escrow changes, penalties, prepayment rules, or taxes. Use as a planning tool and verify with lender-provided amortization schedules.

What if I already have a bi-weekly plan set up through my servicer?

If your servicer simply holds payments and applies them monthly, the effective amortization may match monthly payments. This tool assumes true bi-weekly application (payment applied every half-month). Check your servicer's terms.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 1270f9065c0a

What changed (latest)

v1.0.0 • 2025-11-02 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 2, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-02 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 38f1cdcebd9d