Student Loan Repayment Calculator
Student debt behaves like any amortising loan, but the decisions around it — refinancing, paying extra, or extending the term — move surprisingly large amounts of money. This runs the standard repayment plan and a refinance side by side.
Loan Details
Leave the refinance rate at 0 to skip the comparison.
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What refinancing actually costs you
A lower rate is not automatically a better deal. Refinancing federal student loans into a private loan permanently gives up income-driven repayment, deferment and forbearance rights, and any forgiveness programme eligibility. Those protections have no price tag on a comparison table, which is exactly why they get overlooked.
The number this calculator gives you is the financial half of the decision. If the lifetime saving is small, the protections are almost certainly worth more. If the saving is large and your income is stable, the trade starts to make sense.
The term trap
Refinancing to a lower rate and a longer term almost always lowers the monthly payment while raising total interest. Compare like with like: set the refinance term equal to your remaining term first, see the true saving, then change the term if cash flow is the actual problem you are solving.
How the maths works
Payments use the standard amortisation formula
P = B × i / (1 − (1 + i)−n) where
i is the monthly rate and n the number of months.
Extra payments are applied to principal each month and the schedule is
re-run until the balance clears, which is why the payoff time shortens
faster than most people expect.