Snowball vs avalanche, with real payoff dates.
Debts page → Add debt (balance, APR, min payment). The planner shows snowball and avalanche side by side: months to debt-free and total interest, with an extra-per-month field. It warns you honestly when minimums never retire the balance.
Snowball pays the smallest balance first (quick wins, keeps you motivated). Avalanche hits the highest APR first (cheapest total interest). The planner projects both and tells you the difference outright — "Avalanche saves you $1,240 in interest" — so you pick with eyes open.
Everything above the minimums accelerates the plan. Enter what you could add each month and both projections re-run instantly. Even $50 moves the payoff date meaningfully on high-APR balances.
If your minimums don't cover the interest, the planner says so: this balance never retires. If payoff would take longer than 50 years, it says that too, instead of showing a fantasy date. Both are cues to raise the extra payment — not fine print.