Student Loan Refinance Calculator — Monthly Payment & Lifetime Interest
Student loan refinance calculator: compare APR, payment, and lifetime interest vs federal loans. See tradeoffs. Try free—no signup.
Last updated 2026-05-28 · Davi Baptista
Read also: Full calculator guide, Refinance guide: mortgage, student loans & lease, Mortgage refinance calculator
How it works
Student loan refinance replaces existing loans with a new private loan—this calculator compares lifetime interest and monthly payment against federal protections you may lose.
This student loan refinance calculator shows whether a lower rate or shorter term saves lifetime interest and changes your monthly payment. A refinance calculator student loan users trust should separate payment savings from total cost when you extend or shorten the term. Enter balance, current and new APR, remaining term, and optional fees to compare federal-style burdens with private refinance quotes. Student loan refinance calculator results are estimates—losing income-driven repayment, PSLF, or forbearance can outweigh APR savings. Run the student loan refinance calculator before signing; pair numbers with our refinance guide for mortgage and lease context.
Refinance vs keep federal student loans?
Private student loan refinance replaces existing loans with one new loan at a quoted APR. You typically lose income-driven repayment (IDR), Public Service Loan Forgiveness (PSLF), and federal forbearance.
Refinance when you have stable income, strong credit (often 720+), no PSLF path, and no need for IDR caps. Keep federal loans when forgiveness or payment caps tied to income matter more than a lower rate.
Compare monthly payment and total interest here, then read our cluster guide for mortgage and lease refinance math in the same framework.
Guide, examples, and methodology
Student loan refinance calculator
Compare weighted APR, monthly payment, and lifetime interest on federal or private loans against a private refinance quote. Strong credit and stable income help; losing IDR or PSLF can cost more than rate savings.
Refinance calculator student loan
Some borrowers refinance only private loans while keeping federal loans intact. Consolidating federal loans into private debt is irreversible—run the numbers before you sign.
How to use this student loan refinance calculator
Enter your combined federal and/or private student loan balance, current weighted APR, remaining term in years, and a quoted refinance offer (new APR, new term, optional origination fee). The calculator compares monthly payment, total interest paid, and lifetime savings. Use it before signing a private refinance offer—especially if you are comparing a 10-year aggressive payoff against a 20-year lower payment that adds total interest.
This tool models a single consolidated private loan. It does not replicate income-driven repayment (IDR) caps, Public Service Loan Forgiveness (PSLF) progress, or federal deferment. If any part of your strategy depends on those programs, treat private refinance savings as hypothetical until a certified student loan counselor or CPA confirms you are not giving up more value than you gain in rate reduction.
Example (USD): $45,000 at 6.8% refinanced to 4.9%
| Scenario | Monthly payment | Total interest (illustrative) |
|---|---|---|
| Current: 6.8% APR, 10 years left | ~$518 | ~$17,200 remaining |
| Refi: 4.9% APR, 10 years | ~$475 | ~$12,000 remaining |
| Refi: 4.9% APR, 15 years (lower pay) | ~$354 | ~$18,700 total |
A lower rate with a longer term can reduce your payment but increase lifetime interest versus keeping the original schedule—even when the APR drops. Always compare total interest, not just the new monthly bill. The break-even on any refinance fee is similar to mortgage math: upfront cost ÷ monthly savings ≈ months to recover the fee.
Federal protections you may lose
- Income-driven repayment (IDR) — payments tied to income and family size, with forgiveness after 20–25 years on eligible plans.
- Public Service Loan Forgiveness (PSLF) — forgiveness after 120 qualifying payments while working for eligible employers.
- Death/disability discharge and certain forbearance options tied to federal loan status.
- Future payment pauses or broad forgiveness policies that apply only to federal loans.
Refinance makes the most sense when you have stable W-2 income, credit scores often in the 720+ range for the best rates, no credible PSLF path, and no need for IDR because your payment is already affordable at standard amortization. High earners with graduate PLUS loans at older rates are common refinance candidates—but run the numbers here first.
Private vs federal-only refinance
Some borrowers refinance only private loans while keeping federal loans intact. That preserves federal options on the federal portion while still lowering rate on private debt. If you consolidate federal loans into a private refinance, that conversion is irreversible—you cannot move them back to federal status.
How we calculate
We amortize each scenario with standard fixed-rate installment math: payment = P × [r(1+r)^n] / [(1+r)^n − 1], where P is principal, r is monthly rate, and n is months. Origination fees, if entered, are added to the amount financed. We do not model variable rates, co-signer release, or autopay discounts unless you adjust the quoted APR yourself.
Common mistakes
- Chasing the lowest payment by extending term 5–10 years without comparing total interest.
- Refinancing federal loans during a period when IDR or PSLF is still on the table.
- Ignoring that a co-signer release or death benefit may differ on the new private note.
- Assuming pre-qualification APR equals final underwriting APR after hard credit pull.
- Forgetting to compare against aggressive extra payments on the current loan instead of refinancing.
Related US loan decisions
Student loan refinance is one piece of a household balance sheet. If you also carry a mortgage or auto lease, compare break-even framing across tools: use our mortgage refinance calculator for home debt and the car lease buyout calculator if you are deciding whether to buy out a lease versus accelerating loan payoff.
Related calculators in this topic
- Best Refinance Calculator
- HELOC Payment Calculator
- Lease Buyout Calculator
- Loan Amortization Calculator
Frequently asked questions
Should I refinance federal student loans?
Only if you value net discount over safety. Refinancing federal loans with private banks replaces unique government protections (like income-driven repayments, forbearances, or public service loan forgiveness) with plain commercial debt covenants.
How does changing loan terms affect total cost?
Extending the term to lower monthly dues increases the total interest paid over time. Contracting the term increases monthly payments but compounds huge total lifetime interest savings.
What credit score do I need to refinance?
Many lenders want 650–680+; best rates often 720+. Co-signer can help.
How much can I save refinancing student loans?
Savings ≈ (old rate − new rate) × balance over remaining term, minus fees. Example: $40k from 6.8% to 4.5% on 10 years saves thousands in interest — run your balances here.
Refinance vs income-driven repayment (IDR)?
IDR keeps federal protections and payment caps; private refinance lowers rate but ends forgiveness eligibility. Compare monthly payment and total interest both ways.