Student Loan Payoff Calculator

Frequently Asked Questions

How is my monthly student loan payment calculated?

The standard 10-year repayment uses the same formula as any amortizing loan: payment = principal × (r × (1+r)^n) / ((1+r)^n − 1), where r is the monthly interest rate and n is the number of payments. Each payment covers that month's interest first; the remainder reduces the principal.

How much does an extra $100/month really save?

On a $30,000 loan at 6.5% over 10 years, the standard payment is about $340/month. Adding $100/month cuts payoff time by roughly 2.5 years and saves over $2,500 in interest. The savings are larger the earlier in the loan you start making extra payments, because more of the early payments are interest.

Does this work for federal student loans?

Yes, for standard repayment. Federal loans also offer income-driven repayment plans (IBR, PAYE, SAVE) where your payment is tied to your income rather than your balance — those aren't modeled here. If you're on an IDR plan, this calculator will show the standard payoff as a comparison baseline.

Should I pay off student loans or invest the extra money?

If your loan interest rate is above 6–7%, paying down the debt generally offers a better guaranteed return than investing. Below that threshold — especially if your employer offers a 401(k) match — capturing the match first, then investing, then paying extra on loans is often the optimal sequence. The math depends on your specific rates and tax situation.

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