SAVE Plan vs PAYE: Free Student Loan Calculator Guide

Quick Win: Grab Your Most Recent Tax Return Before You Touch Any Calculator

Before you even open a student loan calculator, pull up your latest tax return. Your Adjusted Gross Income (AGI) is the single number that drives both SAVE and PAYE payment calculations. Without it, you're just guessing. Once you have that figure—plus your current federal student loan balance and the interest rates on each loan—you're ready to run a meaningful comparison in under ten minutes.

Understand What Each Plan Actually Uses as Its Formula

The SAVE Plan Formula

The SAVE plan (formerly REPAYE) calculates your monthly payment as 10% of your discretionary income if you're enrolled in the plan. However, starting in July 2024, this drops to 5% of discretionary income for undergraduate loans. For graduate loans, it remains at 10%. If you have a mix, your payment is weighted between the two.

Here's the critical part: SAVE defines discretionary income as the difference between your AGI and 225% of the federal poverty guideline for your family size and state. That's a much higher shield than older plans.

The PAYE Plan Formula

PAYE sticks with 10% of discretionary income across the board—no reduction for undergraduate loans. It also uses a lower protection threshold: 150% of the poverty guideline. This means more of your income counts as "discretionary," which generally results in a higher payment compared to SAVE.

Run the Numbers: A Concrete Example

Let's say you're a single borrower living in the continental U.S. with the following profile:

• AGI: $50,000
• Family size: 1
• Federal student loan balance: $35,000 (all undergraduate)
• Interest rate: 5.5%

For 2024, the federal poverty guideline for a single-person household in the contiguous 48 states is $15,060.

SAVE Calculation

225% of $15,060 = $33,885
Discretionary income = $50,000 − $33,885 = $16,115
Monthly payment (5% for undergrad) = $16,115 × 0.05 ÷ 12 = $67.15/month

PAYE Calculation

150% of $15,060 = $22,590
Discretionary income = $50,000 − $22,590 = $27,410
Monthly payment (10%) = $27,410 × 0.10 ÷ 12 = $228.42/month

That's a difference of roughly $161 per month—or about $1,930 per year. Over a decade, we're talking nearly $19,000 in payment divergence.

Choose a Free Student Loan Calculator That Handles Both Plans

Not every calculator is built the same. Many free tools only estimate one income-driven plan or use outdated formulas that don't reflect SAVE's 2024 updates. Look for calculators that explicitly mention both SAVE and PAYE, allow you to input your family size, and let you toggle between plans side by side.

The Department of Education's Loan Simulator on StudentAid.gov is the most reliable free option because it pulls official poverty guidelines and applies current plan rules. Third-party calculators from sites like NerdWallet or Bankrate can work for quick estimates, but always verify their SAVE formula includes the 225% threshold and the 5% undergraduate rate.

Input Your Data Accurately—Small Errors Create Big Gaps

When using a free student loan calculator, the accuracy of your inputs determines whether the comparison is worth anything. Here's what to double-check:

• AGI: Use your most recent tax return, not a pay stub. If your income dropped significantly this year, you can submit alternative documentation of current income to your loan servicer.
• Family size: This includes children, spouse, and anyone else you support more than 50%. A larger family size increases your poverty guideline multiplier, which lowers your payment under both plans.
• Loan types: Only Direct Loans qualify for SAVE. PAYE accepts Direct and FFEL loans (if consolidated). Parent PLUS loans are excluded from both unless consolidated under specific rules.
• Graduate vs. undergraduate breakdown: If you have both, the calculator needs to weight them separately under SAVE. This is where many free tools fall short.

Compare Monthly Payments—But Don't Stop There

Monthly payment is the number most borrowers fixate on, and understandably so. It's what hits your bank account every month. But a thorough comparison needs to look at three additional factors:

Total Interest Paid Over the Life of the Loan

SAVE includes an interest subsidy that covers any unpaid interest your monthly payment doesn't cover. This means your balance won't grow from capitalized interest—a significant advantage over PAYE, which also offers a subsidy but only covers up to 50% of unpaid interest for the first three consecutive years.

Forgiveness Timeline

Both plans offer forgiveness after 20 years of qualifying payments for undergraduate loans. SAVE adds a faster path: borrowers with original principal balances under $12,000 can receive forgiveness after just 10 years, with an additional year added for every $1,000 above that threshold. PAYE offers no such accelerated timeline.

Tax Bomb on Forgiveness

Forgiven balances under both SAVE and PAYE may be treated as taxable income at the federal level (currently scheduled to resume in 2026). Some states also tax forgiven debt. Factor this into your long-term planning, especially if you expect a large balance remaining at forgiveness.

Re-Run the Calculator Annually

Your SAVE and PAYE payments aren't locked in forever. Both plans require you to recertify your income and family size annually. A raise, a job loss, a marriage, or a new child can shift your payment significantly.

Make it a habit to revisit your free student loan calculator every year before recertification. If your income dropped, you might see a substantial reduction. If it rose, you'll want to know in advance so you can budget accordingly—and potentially reconsider whether a different repayment strategy makes more sense.

Watch for PAYE's Closing Window

Here's something most calculators won't flag for you: new PAYE enrollments ended on July 1, 2024. If you're already enrolled in PAYE, you can stay. But if you've never been in PAYE, you can't join anymore—SAVE is your primary income-driven option going forward.

This makes the comparison most relevant for borrowers who are currently in PAYE and wondering whether switching to SAVE makes sense. The calculator can show you the monthly difference, but the enrollment deadline means this is a one-way door for most people.

Factor in the SAVE Payment Cap (Or Lack Thereof)

PAYE includes a built-in protection: your payment will never exceed the 10-year Standard Repayment amount, regardless of how high your income climbs. SAVE does not have this cap. If your income grows significantly over time, your SAVE payment could eventually exceed what you'd pay under a standard plan.

For early-career borrowers with lower incomes, this rarely matters in the short term. But if you expect substantial income growth—say, a medical resident transitioning to attending physician pay—run the calculator with projected future income to see where SAVE's lack of a cap becomes a disadvantage.

Make Your Decision Based on Total Cost—Not Just Monthly Cash Flow

A lower monthly payment feels better in the moment, but it can mean paying more over the life of the loan if your income stays moderate and you never reach forgiveness. The reverse is also true: a higher payment under PAYE might build equity faster but cost more month-to-month.

Use the calculator to model both scenarios across your expected repayment horizon. Look at the total amount paid, the projected forgiveness amount, and the tax liability on that forgiveness. The plan with the lowest monthly payment isn't always the cheapest plan in the long run—but with SAVE's interest subsidy and lower percentage for undergraduate loans, it often is.

Run the numbers, revisit them yearly, and let the math—not the marketing—drive your repayment strategy.