Line of Credit Payment & Cost Method, Formula & Examples
On this page
This method guide explains the calculation sequence behind the Line of Credit Payment & Cost Calculator. It owns formulas, input definitions, timing, rounding and reference checks; the calculator remains the only page that performs the numeric scenario.
Calculation sequence
The model applies interest to the drawn balance during the draw phase, then amortizes that balance over the repayment months. It adds annual maintenance and unused-line fees across the modeled term.
Inputs and evidence
Use current written documents for every material input. The calculator supports: Market and currency, Credit limit, Modeled drawn balance, Annual rate, Interest-only months, Repayment months, Annual maintenance fee, Annual unused-line fee.
Reference example
With a 20,000 draw, zero interest and 40 repayment months, principal payment is 500. A 120 annual fee across 52 months adds 520 of modeled fees.
Boundary and error checks
Test zero-rate branches where available, minimum and maximum supported inputs, and a scenario in which the main result reverses. Reject blank, non-finite or out-of-range values rather than silently substituting them.
Model boundary
Future draws, repayments, variable-rate changes, minimum-payment formulas, collateral, approval and tax are excluded.
Sources and review status
Sources and model boundaries checked 2026-10-08. CalculatorGeek Editorial Team verified this page for publication on 2026-10-16. Existing formulas, source dates, model boundaries, and professional-advice limitations remain in force.
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