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Student Loan Payoff Calculator

See how quickly you can pay off your student loans by adding extra payments. Compare your standard repayment timeline with an accelerated plan, view income-driven payment estimates, and see exactly how much interest you can save.

Student loan repayment is uniquely complicated in the U.S. because federal loans have multiple repayment plans, potential forgiveness pathways, and tax implications, while private loans operate like standard fixed-rate term loans. The right strategy depends on whether your loans are federal or private, your income trajectory, and whether you plan to qualify for forgiveness programs.

This calculator covers the basic math: standard repayment timeline, savings from extra payments, and rough income-driven payment estimates for federal loans. Enter your balance, rate, and current payment along with optional extra monthly payments, and see how quickly the loan clears under each scenario.

Two big strategic forks to know: 1. **Federal vs private**: federal loans (Direct, Stafford, Grad PLUS) offer income-driven plans, forgiveness options, and deferment protections. Private loans don't. Don't refinance federal loans into private unless you've ruled out forgiveness. 2. **Standard vs IDR vs PSLF**: if you work in qualifying public service for 10 years (120 monthly payments) on an income-driven plan, the remaining balance is forgiven tax-free via Public Service Loan Forgiveness. For high-balance borrowers headed to lower-paying public service, the math often favors minimum IDR payments — not extra payments.

Inputs

$
%
$
$
$

Used to estimate income-driven payments

%

Percent of discretionary income (IBR/PAYE/REPAYE)

Results

Payoff Time (w/ Extra)

7y 1m

Interest Saved

$2,532.34

Time Saved

28 months

Income-Driven Payment

$270.08

Total Interest: Standard vs Accelerated

Remaining Balance Over Time

Yearly Breakdown

YearStandard BalanceAccelerated BalanceStandard PaidAccelerated Paid
1$32,051.41$30,820.69$4,800.00$6,000.00
2$28,936.49$26,405.63$9,600.00$12,000.00
3$25,645.87$21,741.54$14,400.00$18,000.00
4$22,169.63$16,814.34$19,200.00$24,000.00
5$18,497.30$11,609.22$24,000.00$30,000.00
6$14,617.83$6,110.49$28,800.00$36,000.00
7$10,519.52$301.58$33,600.00$42,000.00
8$6,190.04$0.00$38,400.00$42,302.96
9$1,616.34$0.00$43,200.00$42,302.96
10$0.00$0.00$44,835.30$42,302.96
Last updated: Reviewed by the CalcMountain editorial team

Formula

Standard payoff months at fixed payment P: n = −ln(1 − (B × r) / P) / ln(1 + r) Where: B = Loan balance r = Monthly rate (annual rate / 12) P = Monthly payment Total interest paid: Total interest = P × n − B Income-driven payment estimate (simplified): Discretionary income = Annual income − 150% × Federal poverty guideline Monthly IDR payment = (Discretionary income × IDR %) / 12 Example: $35K balance, 5.5%, $400/mo r = 0.00458 n = −ln(1 − (35000 × 0.00458) / 400) / ln(1.00458) ≈ 105 months ≈ 8.75 years Total interest: $400 × 105 − $35,000 ≈ $7,000 With $100 extra ($500/mo total): payoff drops to ~78 months, interest savings ≈ $1,900

How to use this calculator

  1. Enter your total loan balance (sum of all loans if multiple). For separate strategies, run the calculator per loan.
  2. Enter the interest rate. For multiple loans, use a weighted average if running combined.
  3. Enter current minimum monthly payment.
  4. Enter any extra monthly payment you can commit to.
  5. Enter annual income to see an income-driven payment estimate. This is rough — actual IDR payments depend on your specific plan, family size, and the 2024 poverty guidelines.
  6. Compare scenarios: standard payoff vs accelerated vs income-driven. For federal loan borrowers, factor in whether you might pursue PSLF or other forgiveness.

Worked examples

Standard repayment + small extras

$35K balance at 5.5%, $400/mo standard payment. Standard timeline: 10 years, $10,800 total interest With $100 extra ($500/mo): 7 years, $7,300 interest The $100/month extra saves $3,500 and clears 3 years sooner.

PSLF pathway

$110K federal loan balance, public service job earning $55K. Standard 10-year: payments ~ $1,195/mo, total $143K paid PSLF + IDR (REPAYE 10%): ~$310/mo for 10 years = $37K paid Remaining ~$140K balance forgiven tax-free at year 10 PSLF math is dramatic for high-balance borrowers in qualifying public service. The catch: you must work full-time at a qualifying employer for 120 payments, and the rules around qualifying payments have been moving targets.

When to use this calculator

Use this for federal or private student loan planning. Some additional considerations:

For federal loans, before adding extra payments, decide: - Are you eligible for PSLF (public service, qualifying employer)? - Could income-driven repayment work better than standard? - Will you have a long enough income trajectory to make standard repayment + extras worthwhile?

For private loans, the strategy is simpler — just standard amortization math. Extra payments save interest; refinancing to lower rates saves more. Watch interest-only periods and variable-rate provisions.

The federal RAP plan (Repayment Assistance Plan) was introduced in July 2026 to replace the prior SAVE plan. Check current IRS, ED, and StudentAid.gov guidance for the latest specifics on federal IDR plans.

Common mistakes to avoid

  • Refinancing federal loans into private without considering PSLF or forgiveness eligibility. This is a one-way door.
  • Paying extra on federal loans while in a PSLF-track job. Extra payments don't accelerate PSLF — they just reduce the balance that would have been forgiven.
  • Choosing the wrong IDR plan for your situation. SAVE, IBR, PAYE, ICR, and the new RAP plan have different terms. Use StudentAid.gov's plan loan simulator.
  • Forgetting that non-PSLF forgiveness (20–25 years of IDR payments) is currently taxable as ordinary income. A $40K forgiveness at year 25 could trigger a $10K+ tax bill.
  • Treating private and federal loans the same. They're not — federal loans have far more borrower protections.
  • Not consolidating strategically. Consolidation can simplify, but also resets clocks on some forgiveness programs.

Frequently Asked Questions

Sources & further reading

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