Student Loan Repayment Comparison Calculator

What this comparison does

Federal student loans offer a standard fixed plan and several income-driven repayment (IDR) options. The standard plan retires the loan in a fixed term, usually ten years. Income-driven plans stretch the term to twenty or twenty-five years, cap the monthly payment at a percentage of discretionary income, and forgive whatever remains at the end.

The trade-off is simple to state and hard to feel: lower payments now, more interest and a longer obligation later, with forgiveness as the offset.

How the income-driven estimate is built

The calculator follows the standard IDR arithmetic:

1. Discretionary income = gross income − 150% of the poverty guideline for your family size.
2. Annual payment = your chosen share (default 10%) of discretionary income.
3. Monthly payment = annual payment ÷ 12.
4. Income is grown annually at the rate you enter, and the payment is recalculated each year.
5. After the forgiveness term, any remaining balance is treated as forgiven.

The poverty guideline is a built-in approximation of the HHS figures for a one-person household plus an allowance per additional family member. It is editable indirectly through the income and family-size inputs, but it is not a live lookup, so check the current HHS table if precision matters.

Why the answer is not "pick the lower payment"

A lower payment is only better if the alternative is default or if forgiveness is realistically in reach. Three questions decide it:

Will your income rise faster than your balance falls? IDR payments scale with income. A borrower who starts at $45,000 and reaches $95,000 in eight years may pay more under IDR than under the standard plan, with no forgiveness at the end.

Is the forgiven amount taxable? Tax treatment of forgiven student debt has changed repeatedly. If forgiveness is taxable in your situation, a large forgiven balance can create a tax bill with no cash to pay it. The calculator estimates at a flat 22% and labels it clearly as an estimate.

Do you qualify? IDR eligibility depends on loan type, consolidation history, and payment counts. Private loans are not eligible at all.

What "discretionary income" leaves out

The formula uses gross income and a poverty guideline. It does not account for housing costs, childcare, medical expenses, or dependents beyond the family-size adjustment. Households in expensive cities often find the calculated payment higher than their actual budget allows. Filing status and spousal income can also change the result — married borrowers filing separately sometimes qualify for a lower payment.

The standard plan's hidden advantage

A ten-year standard payment is higher, but it eliminates the balance with the least interest, and it preserves optionality. You can always switch to IDR if income drops. Going the other direction — from IDR to standard — resets the clock and may forfeit progress toward forgiveness.

Practical steps

1. Confirm your loan types and servicer in the Federal Student Aid dashboard.
2. Compare your servicer's official payment estimate against this model; use the servicer figure for decisions.
3. If you choose IDR, recertify income on time every year. Missing recertification can push the payment back to the standard amount.
4. Track qualifying payments if forgiveness is your strategy.
5. Revisit the comparison after any significant income change.

Private loans

Private student loans do not offer IDR or federal forgiveness. Refinancing can lower the rate for borrowers with strong credit, but it converts federal protections into a private obligation. Model the refinance with the amortization calculator and treat the loss of income-driven flexibility as a real cost.