Student Loan Payoff Calculator
Find out how many months it takes to pay off your student loans under standard or extended repayment, and see how extra monthly payments shorten your timeline. Covers federal and private loans.
About this calculator
Student loan payoff calculations rely on the standard amortization formula to first determine the required monthly payment: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the loan balance, r is the monthly interest rate (annualRate / 100 / 12), and n is the number of payments in the chosen plan (120 for standard 10-year, 300 for extended 25-year). Any extra monthly payment is added to M. The calculator then simulates repayment month by month: balance = balance × (1 + monthlyRate) − totalPayment, counting months until the balance reaches zero. The grace period (typically 6 months after graduation for federal loans) is added to give the full calendar timeline from graduation to payoff.
How to use
Assume a $35,000 balance at 6.5% interest on a standard 10-year plan with $100 extra per month and a 6-month grace period. Monthly rate = 6.5 / 100 / 12 = 0.005417. n = 120. Base payment = 35,000 × [0.005417 × (1.005417)¹²⁰] / [(1.005417)¹²⁰ − 1] ≈ $396. Total monthly payment = $396 + $100 = $496. Simulating month by month, the balance hits zero in approximately 83 months. Adding the 6-month grace period gives a total of 89 months (about 7.4 years) from graduation — saving roughly 17 months versus the base plan.
Frequently asked questions
How much faster can extra monthly payments pay off student loans?
Extra payments reduce your principal faster, which means less interest accrues each month and a growing share of each subsequent payment attacks the balance directly. On a $35,000 loan at 6.5%, adding just $100/month to the standard payment can cut repayment by 1–2 years and save over $2,000 in interest. Larger extra payments produce even more dramatic savings — $200 extra per month on the same loan can eliminate it nearly 3 years early.
What is the difference between standard and extended student loan repayment plans?
The standard plan spreads payments over 10 years (120 months) with higher fixed monthly payments, resulting in less total interest paid. The extended plan stretches to 25 years (300 months), lowering monthly payments substantially but dramatically increasing total interest — sometimes doubling it. Extended plans make sense when cash flow is tight in early career years, but borrowers should switch to the standard plan or make extra payments as soon as their income allows to minimize long-term cost.
When does the grace period start and how does it affect student loan repayment?
For most federal student loans, the grace period is a 6-month window after you graduate, leave school, or drop below half-time enrollment during which no payments are required. However, interest continues to accrue on unsubsidized loans during this period, adding to your principal when repayment begins — a process called capitalization. This calculator adds the grace period to the repayment month count so you can see the full time from graduation to your final payment, helping you plan your post-graduation budget accurately.