Cernarus

Student Loan Amortization Calculator with Bi-Weekly Payments

This calculator models loan amortization under different payment frequencies, with a primary focus on bi‑weekly schedules (26 payments per year). It supports additional per‑period or annual extra payments and provides an apples‑to‑apples interest and payoff time comparison versus monthly payments.

Results are numerical estimates produced by closed‑form formulas and algebraic inverses of the annuity formula. Iterative amortization, rounding rules applied by your servicer, or special plan rules (for example, federal income‑driven repayment, forgiveness, or capitalization differences) may change real outcomes; see accuracy notes and citations below.

Updated Nov 23, 2025

Calculates monthly and bi‑weekly scenarios using the same principal, rate, term and extra payments and reports interest and time differences.

Inputs

Advanced inputs

Custom frequency

Results

Updates as you type

Monthly payment (with extras)

$212.13

Biweekly payment (with extras)

$97.82

Total interest — monthly

—

Total interest — biweekly

—

Interest saved (monthly − biweekly)

—

Payoff time difference (years)

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OutputValueUnit
Monthly payment (with extras)$212.13USD
Biweekly payment (with extras)$97.82USD
Total interest — monthly—USD
Total interest — biweekly—USD
Interest saved (monthly − biweekly)—USD
Payoff time difference (years)—years
Primary result$212.13

Visualization

Methodology

We compute periodic rate = APR / periods_per_year, scheduled payment from standard annuity formula, then convert user extras into an equivalent per‑period amount. When extras increase the periodic payment, the number of payments to payoff is computed by inverting the annuity relation (or dividing principal by payment for zero interest).

For comparisons we calculate both scenarios with identical principal, APR and term, and report total interest and estimated payoff time. When the servicer applies different compounding or rounding rules, results will vary; the tool reports conservative, algebraic estimates rather than a servicer’s official payoff quote.

Key takeaways

Use the bi‑weekly method to see how 26 payments/year compares to monthly schedules. Enter extra per‑period or annual amounts to evaluate their effect on payoff time and total interest.

For official payoff numbers, request a servicer payoff statement. This tool follows standard financial formulas and includes conservative numeric checks; actual servicer posting and plan rules can change outcomes.

Further resources

Expert Q&A

Does making bi‑weekly payments always save interest?

If bi‑weekly payments total the same annual amount as monthly payments, simple timing differences alone may produce modest savings; larger savings occur when bi‑weekly results in more frequent payments that reduce average daily balance. This calculator assumes identical APR and compounding; servicer rounding and how the servicer posts payments also affect actual savings.

Are the results exact payoff quotes?

No. These are algebraic estimates. Servicers may post payments, apply rounding, charge fees, or have specific rules for extra payments that change the payoff schedule. For a binding payoff amount, request a payoff statement from your servicer.

Can I model one‑time lump sums or changing payments?

This version converts annual lump sums into equivalent per‑period amounts. Modeling arbitrary changing payments or scheduled lump sums at precise dates requires iterative amortization and a date calendar; use a servicer payoff quote for exact timing effects.

How accurate is the calculator and what safeguards are used?

We use closed‑form financial formulas and algebraic inverses. Numeric safeguards guard against division by zero and invalid log arguments. Accuracy is subject to floating point limits; results are intended for planning and comparison, not legal payoff statements.

Sources & citations