Personal Loan Refinance Calculator
This calculator helps you compare an existing personal loan to a refinance offer and shows the effects of switching between monthly and bi‑weekly payments. It reports payment amounts, total interest paid, estimated interest savings, and term differences for both schedules.
Use the refinance comparison when you want a side‑by‑side view of current vs refinance under monthly and bi‑weekly frequency. Use the bi‑weekly impact method to evaluate how changing the payment cadence on a single loan affects interest and payoff timing.
Governance
Record 65a8a1e98bc7 • Reviewed by Fidamen Standards Committee
Compare current loan and refinance offer across both monthly and bi‑weekly schedules, showing payments, total interest paid, and interest savings.
Inputs
Results
Current monthly payment
$198.01
Current bi‑weekly payment
$91.27
Refinance monthly payment
$188.71
Refinance bi‑weekly payment
$87.01
Current total interest (monthly)
$1,880.72
Refinance total interest (monthly)
$1,322.74
Interest savings (monthly)
$557.98
Current total interest (bi‑weekly)
$1,865.19
Refinance total interest (bi‑weekly)
$1,311.59
Interest savings (bi‑weekly)
$553.60
Term difference (months, monthly)
0
| Output | Value | Unit |
|---|---|---|
| Current monthly payment | $198.01 | USD |
| Current bi‑weekly payment | $91.27 | USD |
| Refinance monthly payment | $188.71 | USD |
| Refinance bi‑weekly payment | $87.01 | USD |
| Current total interest (monthly) | $1,880.72 | USD |
| Refinance total interest (monthly) | $1,322.74 | USD |
| Interest savings (monthly) | $557.98 | USD |
| Current total interest (bi‑weekly) | $1,865.19 | USD |
| Refinance total interest (bi‑weekly) | $1,311.59 | USD |
| Interest savings (bi‑weekly) | $553.60 | USD |
| Term difference (months, monthly) | 0 | months |
Visualization
Methodology
Payments are computed using standard amortizing loan formulas. For a payment period rate r and number of periods n, payment = (r * principal) / (1 - (1 + r)^(-n)). Annual rates are converted to period rates by dividing by 12 for monthly schedules and 26 for bi‑weekly schedules.
Total interest paid is computed as total payments (payment × number of periods) minus the principal (or effective principal when fees are added). Interest savings are the difference in total interest between scenarios. Calculations assume fixed interest rates and that payments are made on schedule with no prepayments unless reflected in inputs.
Key takeaways
This advanced calculator produces comparable outputs for monthly and bi‑weekly schedules and for current versus refinance offers. Use it to quantify payment differences, estimated interest savings, and term differences.
For regulatory or contract precision, rely on official lender disclosures (including APR and amortization schedules). This tool is for planning and comparative use only.
F.A.Q.
Does dividing a monthly payment by two give the correct bi‑weekly payment?
No. A true bi‑weekly schedule uses 26 payments per year and a per‑period interest rate based on 26 periods annually. Simply halving the monthly payment is an approximation and can misstate interest and payoff timing.
Are closing costs included in the refinance principal?
This tool includes a field for refinance fees. If you add fees, they are added to the refinance principal for calculation. Consider whether fees are financed or paid up front when interpreting results.
What should I watch for when comparing offers?
Compare effective principal (including financed fees), the annual percentage rate (APR) where available, the total interest over the term, and any prepayment penalties or differences in term length. This calculator assumes fixed nominal rates and does not model APR adjustments, fees outside financed principal, or lender‑specific terms.
How accurate are the results?
Results use standard amortization math. They are suitable for estimates and decision support but not a substitute for lender disclosures. See the accuracy caveats and standards references provided.
Sources & citations
- NIST - Numerical Methods and Validation Guidance — https://www.nist.gov
- ISO - Standards for software and numerical accuracy — https://www.iso.org
- IEEE - Best practices for algorithm validation — https://standards.ieee.org
- OSHA - Guidance on trustworthy system processes — https://www.osha.gov
- CFPB Regulation Z — 12 CFR § 1026.22 Determination of Annual Percentage Rate — https://www.consumerfinance.gov/rules-policy/regulations/1026/22/
- CFPB Appendix J — Annual Percentage Rate Computations for Closed-End Credit — https://www.consumerfinance.gov/rules-policy/regulations/1026/j/
- CFPB Annual Percentage Rate Tables — https://www.consumerfinance.gov/compliance/compliance-resources/other-applicable-requirements/annual-percentage-rate-tables/
Further resources
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
Record ID: 65a8a1e98bc7What changed (latest)
v1.0.0 • 2025-11-14 • 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
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
What changed (latest)
v1.0.0 • 2025-11-14 • 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 14, 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 • 2025-11-14 • 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: f37827f93e53
- https://standards.ieee.org
- https://www.consumerfinance.gov/compliance/compliance-resources/other-applicable-requirements/annual-percentage-rate-tables/
- https://www.consumerfinance.gov/rules-policy/regulations/1026/22/
- https://www.consumerfinance.gov/rules-policy/regulations/1026/j/
- https://www.iso.org
- https://www.nist.gov
- https://www.osha.gov