Every extra dollar goes straight at principal. Here is exactly how many months that removes from the loan, and what it saves you in interest.
Both extras go to principal, never to interest. The lump sum lands in month one. Leave both at $0 to see your baseline schedule with no acceleration.
It depends on your loan size, rate, and how early you start — even modest extra principal payments early in the loan term can meaningfully cut total interest paid.
This is a personal finance tradeoff between guaranteed interest savings and potential investment returns — consult a financial advisor for your specific situation.
Not always — confirm with your servicer that extra payments are applied to principal, not just future scheduled payments.