A genuinely complicated moment for federal student loan rules
Federal student loan repayment is mid-overhaul in 2026. Legislation signed in 2025 restructured the repayment landscape, phasing out several older income-driven plans and introducing a new one, with different rules depending on whether your loans were disbursed before or after July 1, 2026. This calculator models the general mechanism shared by the more established income-driven plans — a payment based on a percentage of income above a protected threshold — rather than any single named plan, since which specific plan you actually qualify for depends on your loan history. Confirm your exact options at studentaid.gov or with your loan servicer before making a repayment decision.
How “discretionary income” is actually defined
Discretionary income isn’t your full salary — it’s your income above a protected amount tied to the federal poverty guidelines for your household size, adjusted annually by HHS. This calculator uses the official 2026 guidelines directly: a single person’s protected amount is $23,940 (150% of the $15,960 poverty line), with roughly $8,520 added for each additional household member. Only income above that threshold counts toward your IDR payment calculation.
Why the standard plan and IDR can lead to wildly different totals
The standard 10-year plan is a straightforward amortization, like a mortgage — a fixed payment that guarantees payoff in exactly 10 years, with a predictable total interest cost. An income-driven payment is calculated independently of your balance or interest rate, based purely on your income. On a large balance with a modest income, the IDR payment can be lower than the interest accruing each month — meaning the balance actually grows for years before eventual forgiveness, rather than shrinking the way a standard payment does.
The forgiveness trade-off
Most income-driven plans forgive any remaining balance after a set number of years of qualifying payments — 20 years is common for the plans this calculator’s structure is based on. That forgiveness is valuable, but it isn’t free in every sense: forgiven student loan debt has, at various points, been treated as taxable income at the federal level, and state tax treatment varies independently. Whether forgiveness is currently taxable in your situation is exactly the kind of detail that changes with legislation, so verify current treatment before counting on it as a clean outcome.
Using this calculator
Enter your actual current income, not a projected future salary — if you expect meaningful income growth, your real IDR payments will rise over time as your discretionary income grows, which this calculator (holding income constant) doesn’t capture. Treat the IDR side of this comparison as a rough current-year estimate of the mechanism, not a locked-in 20-year forecast.
This article is for educational purposes only and isn't legal, financial, or tax advice. See our Disclaimer for details.
