Calculation methodology

How Runway models a debt payoff plan.

This page exists so users can evaluate the planner’s assumptions in public. The methodology is authored by Eisen Labs / Runway product and reflects the current debt payoff engine used in the app.

Daily periodic interest calculations based on current APR or promo APR state
Minimum payment handling, including percentage-based minimums where configured
Snowball, avalanche, and custom ordering behavior
Extra-payment allocation and one-time scenario effects
Payment timing assumptions and why lender statements can differ
Rounding and fee limitations that affect real-world results

Interest handling

Runway models interest as balances change over time, including promo APR handling where configured. Real lender statements can still differ because fees, posting times, or lender-specific rounding rules are outside the product’s control.

Minimum payment handling

The planner covers fixed minimums and percentage-based minimums. Minimum obligations are satisfied before extra money is redirected according to the selected payoff strategy.

Strategy handling

Avalanche prioritizes highest APR. Snowball prioritizes the smallest balance. Custom order follows the sequence the user sets. The useful comparison keeps the debt budget constant and changes only the order.

What this methodology page is for

This page is part of Runway’s public trust surface. It exists so users can inspect the calculation behavior before relying on the planner and so search traffic lands on pages connected to real product logic rather than generic finance copy.