List loans separately
Do not mash federal and private balances into one line. Avalanche needs the real APRs. Snowball needs the real balances. Combine only if two loans share the same rate and servicer and you already treat them as one payment.
Federal vs private
- Federal: Keep making at least the billed minimum so you stay current. Extra dollars can still follow avalanche (highest rate first) even if the servicer applies them differently — call and specify “apply extra to this loan ID.”
- Private: Often higher rates and fewer protections. These usually deserve avalanche priority unless a tiny private balance is blocking motivation.
Extra payments and snowflakes
A tax refund or signing bonus is a snowflake: one month, one amount. Schedule it in the calculator and the debt-free date jumps. Recurring extra (overtime, renting a room) belongs on the slider so you feel the live change.
Income-driven plans
This tool models amortization with a fixed minimum. If your federal payment is income-driven and may not cover interest, treat the billed amount as the minimum and know the calendar date is an estimate unless you pay enough to stop negative amortization. Use the vs-minimums card to see how much time extra buys versus the billed floor.