Cernarus

Student Loan Payment Calculator

This calculator compares standard monthly amortization and two bi‑weekly approaches: a true 26‑period amortization and the common accelerated technique of paying half the monthly payment every two weeks. Outputs estimate payment amount, number of payments until payoff, total amount paid, and total interest.

Results are estimates. They assume a fixed interest rate, equal payment amounts for the selected schedule, and that extra amounts are applied directly to principal at each scheduled payment date. Use the comparison to understand potential interest savings and earlier payoff from more frequent payments.

Updated Nov 26, 2025

Pay half of the standard monthly payment every two weeks. Because there are 26 bi‑weekly periods per year, this approach results in the equivalent of 13 full monthly payments per year and accelerates payoff. Supports adding an extra amount to each bi‑weekly occurrence.

Inputs

Results

Updates as you type

Bi‑weekly payment (accelerated, with extra)

$162.79

Number of bi‑weekly payments

233.7889

Total interest (accelerated)

$8,058.36

Payoff time (years)

8.9919

OutputValueUnit
Bi‑weekly payment (accelerated, with extra)$162.79—
Number of bi‑weekly payments233.7889periods
Total interest (accelerated)$8,058.36—
Payoff time (years)8.9919years
Primary result$162.79

Visualization

Methodology

Calculations use standard amortization mathematics: periodic interest = annual APR divided by the number of periods per year. For monthly calculations the formula M = P*r/(1-(1+r)^-n) is used where r is the monthly rate and n the number of months. For period-based schedules the same annuity formula is applied with the period rate and period count.

The accelerated bi‑weekly option models making half the monthly amortizing payment every two weeks (26 payments/year). Because 26 half‑payments equal 13 full monthly payments per year, this accelerates principal reduction. The bi‑weekly amortization option computes a periodic payment that amortizes the loan exactly over term_years×26 periods.

Standards and good practice referenced: follow secure coding and data handling per NIST guidance for cryptographic and data protection controls; numeric accuracy and algorithm documentation principles align with ISO numerics and IEEE floating point recommendations; workplace and safety guidance cited from OSHA where relevant to application deployment. This tool is informational, not legal or financial advice.

Worked examples

Example 1: $30,000 balance, 5.5% APR, 10 years remaining. Monthly schedule will produce a fixed monthly payment; accelerated bi‑weekly (half monthly every two weeks) typically yields an earlier payoff and lower total interest because of the extra annual payment equivalent.

Example 2: Adding a small extra amount to each bi‑weekly payment increases principal reduction and shortens payoff faster than the same extra split into monthly payments, because extra amounts are applied more frequently.

Key takeaways

Bi‑weekly accelerated (half monthly every two weeks) often reduces interest and shortens payoff relative to monthly payments because it results in one extra full monthly payment per year. True bi‑weekly amortization computes payments to fully amortize across 26×term years periods and may produce different per‑period amounts.

Use the calculator to compare methods with and without extra contributions. Consider rounding behavior and bank processing timing; actual results depend on your servicer's posting practices.

Further resources

External guidance

Expert Q&A

Does the calculator account for loan servicer fees or payment posting timing?

No. This estimator assumes payments are applied immediately and fully to balance and interest as scheduled. Servicer fees, daily interest accrual methods, grace-periods, prepayment penalties, or specific posting delays can change real outcomes.

Is accelerated bi‑weekly always better than monthly?

Accelerated bi‑weekly usually reduces total interest compared with identical monthly payments because it results in extra principal payments each year, but the size of the benefit depends on interest rate, balance, term, and whether your servicer treats payments as applied immediately to principal.

How accurate are the numbers?

Numbers are mathematical estimates based on fixed APR and regular payment timing. They are subject to rounding, floating point limits, and real‑world factors such as variable rates, capitalization rules, and how a servicer posts payments. See accuracy and standards citations below.

Sources & citations