Fidamen

Student Loan APR Calculator

This calculator compares standard monthly amortization with a bi‑weekly schedule (26 payments per year). It shows periodic payments, total paid, total interest, and the effective annual percentage rate implied by the chosen nominal APR.

Use the tool to estimate savings from more frequent payments and to understand how nominal APR maps to effective annual cost when payment frequency changes.

Updated Nov 16, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 42c9d81814a9 • Reviewed by Fidamen Standards Committee

Compute fixed bi‑weekly payments assuming interest is applied per bi‑weekly period (26 periods per year). This method treats the nominal APR divided by 26 as the period rate.

Inputs

Results

Updates as you type

Bi‑weekly payment

$97.82

Total paid

$25,433.77

Total interest

$5,433.77

Effective APR (annual)

512.21%

Number of bi‑weekly payments

260

OutputValueUnit
Bi‑weekly payment$97.82USD
Total paid$25,433.77USD
Total interest$5,433.77USD
Effective APR (annual)512.21%%
Number of bi‑weekly payments260—
Primary result$97.82

Visualization

Methodology

Calculations assume fixed-rate amortizing loans with interest accrued per payment period. Monthly calculations use 12 periods per year; bi‑weekly calculations use 26 periods per year. Period rate = nominal APR / periods per year.

Effective APR is computed as (1 + period_rate)^(periods_per_year) − 1 and expressed as an annual percent. Where lenders use daily interest accrual or different compounding conventions, results are estimates.

Accuracy and security guidance: numeric accuracy targets follow best practices for reproducible financial computation. Implementation and data handling should follow NIST guidance for secure numerical libraries and ISO/IEC recommendations for numeric data interchange. This tool does not provide legal, tax, or regulatory advice; consult an advisor for compliance-specific questions.

Worked examples

Example 1: $20,000 principal, 5% APR, 10 years. Compare monthly payment vs bi‑weekly payment and see total interest difference.

Example 2: Add a $10 extra payment per bi‑weekly period to see the impact on interest saved and earlier payoff.

F.A.Q.

Does the bi‑weekly option always save money?

If bi‑weekly payments increase the number of payments per year (for example paying half of the monthly payment every two weeks results in 13 monthly equivalents), you typically reduce interest and shorten term. Savings depend on how interest is accrued; this calculator assumes per‑period compounding and shows the estimate.

What is the difference between nominal APR and effective APR?

Nominal APR is the stated annual percentage rate. Effective APR reflects compounding for the chosen payment frequency and equals (1 + period_rate)^(periods_per_year) − 1.

Are results exact for every lender?

No. Lenders may use daily accrual, different compounding conventions, fees, or rounding rules. Use these results as close estimates and verify with your loan servicer for exact payoff schedules.

Is extra payment applied to principal immediately?

This calculator treats extra payment as applied at each period in addition to the scheduled payment, reducing principal and interest in subsequent periods. Verify with your servicer how they apply extra payments.

Sources & citations

Further resources

External guidance

Versioning & Change Control

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

Record ID: 42c9d81814a9

What changed (latest)

v1.0.0 • 2025-11-16 • 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 16, 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 • 2025-11-16 • 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: f0ea2d7683f9