Snowball and avalanche are good arithmetic. They answer one question well: given a set of balances and rates, which do you attack first. For a federal student loan borrower on an income driven plan, that is not the question that decides the outcome, and the gap is large enough to be worth showing rather than asserting.
Every figure below is computed live by the Finology engine, parity verified, and independently checkable at the verify URL at the bottom of this page.
This is a published reference scenario, served from our public API so it cannot quietly drift from what the engine actually does.
A payoff strategy reads this as two debts. Avalanche attacks the 5.60% loan first. Snowball attacks the $18,800 loan first. Both answers are internally correct, and for this borrower neither one changes the outcome, because both loans reach forgiveness together at the same month.
Computed 30 September 2026 under rule version rl1-ff59950a0f31bf1b.
Forgiveness reached in 60 months
Forgiveness reached in 60 months
Balance cleared in 60 months
The distance between the lowest cost path and retiring the balance, for this borrower, over the same five years. A payoff plan has no field in which this number can appear, because nothing in a balance and a rate expresses the fact that the remaining balance is cancelled at month 60.
On an income driven plan the monthly payment comes from adjusted gross income, family size and filing status. Paying extra does not lower it, and does not move the forgiveness date closer.
Every additional dollar of principal reduces a balance that was going to be cancelled. The borrower pays it in order to not have it forgiven, which is the opposite of the intent behind the payment.
Avalanche ranks the 5.60% loan above the 4.45% loan. Both are forgiven in the same month, so the ranking has no effect on what this borrower pays.
What we are not claiming. We are not saying a general purpose assistant returns $123,710. It returns a payoff schedule, and a payoff schedule is a reasonable answer to the question it was asked. The claim is narrower and easier to check: the debt elimination frame has no representation for forgiveness, so the action it recommends moves this borrower along the axis whose far end the engine prices at $123,710. The frame cannot price that move. The engine can.
Every answer the engine produces is recorded with an identifier and can be re-read later by anyone, with no key and no account.
44d06723-5ed3-4d71-b260-501534fc4748rl1-ff59950a0f31bf1b, computed 2026-09-13.Finology Software builds the student loan engine financial advisors use to load a book of borrowers, keep it current as the rules move, and produce a client ready report with every figure cited and dated.