Student Loan Calculator

How to use this calculator

The Student Loan Calculator has four tabs, each designed for a different planning scenario.

Standard Repayment is the baseline. Enter your Loan Balance, Interest Rate, and Loan Term (in years, defaulting to 10 for federal loans). The calculator shows your fixed monthly payment, total amount paid, and total interest over the life of the loan. Every payment is identical, and the loan pays off at exactly the end of the term.

Graduated Repayment uses the same three inputs but adds a Payment Increase Frequency field (typically every 2 years, which is the federal standard). Payments start lower than the standard plan and increase on a set schedule. Enter your starting payment or let the calculator derive it from the loan terms. The output shows how each payment tier changes and the total interest cost compared to the standard plan.

Income-Based Repayment (IBR) requires two additional inputs: Annual Gross Income and Family Size. These determine your discretionary income, which the federal formula defines as the amount above 150% of the federal poverty guideline for your family size. Your monthly payment is 10% of that discretionary income (under the new SAVE plan; older IBR uses 10% to 15% depending on when you first borrowed). The calculator also shows your projected forgiveness amount if you remain on the plan for 20 or 25 years.

Multi-Loan lets you enter up to six separate loans with different balances and interest rates. It calculates the combined monthly payment under each plan and shows the aggregate total interest, making it useful for borrowers who took out multiple federal or private loans across different school years.

What repayment plan choice actually costs you

Most borrowers pick a repayment plan when they first log into their loan servicer’s portal and never revisit it. That’s a significant financial decision made with very little analysis.

The plan you choose determines your monthly cash flow for the next 10 to 25 years and the total interest you pay over that period. Those two numbers often pull in opposite directions. Lower monthly payments mean more cash now but dramatically more interest paid over time. Higher payments hurt your budget today but slash total cost.

The difference between the Standard and Graduated plans on a $40,000 loan can easily exceed $2,500 in extra interest. The difference between Standard and a 25-year IBR plan can exceed $15,000. These are not rounding errors. They're major financial outcomes shaped by a single enrollment decision.

Understanding each plan’s mechanics before you choose is the highest-value financial education a student loan borrower can get.

The three federal repayment plans explained

Standard Repayment

The Standard 10-year plan is the default for federal Direct Loans. Payments are fixed, the amortization schedule is predictable, and no interest forgiveness is available because the loan pays off in full. Your payment is calculated using a standard amortization formula:

M = P x [r(1+r)^n] / [(1+r)^n - 1]

Where M is the monthly payment, P is the principal, r is the monthly interest rate (annual rate / 12), and n is the total number of payments.

This plan always produces the lowest total interest cost among federal repayment options because you pay the debt off the fastest.

Graduated Repayment

Graduated repayment starts your payments lower than the Standard plan and increases them every two years for up to 10 years. The assumption is that your income will grow, making the higher payments more manageable later. The total repayment period is also 10 years, so you don’t get a longer term.

The catch: because you’re paying less in the early years, more of your balance accrues interest before it’s paid down. Total interest paid is always higher than Standard, sometimes by 15% to 25%.

Graduated makes sense if your current income genuinely can’t support standard payments but you expect meaningful salary growth within a few years. It does not make sense as a long-term income-management strategy: for that, IBR is more appropriate.

Income-Based Repayment (IBR) and SAVE

IBR and the newer SAVE (Saving on a Valuable Education) plan tie your monthly payment to your income rather than your loan balance. The formula:

Monthly Payment = 10% x (Adjusted Gross Income - 1.5 x Federal Poverty Guideline) / 12

The federal poverty guideline varies by family size and is updated annually. For 2024, the 150% threshold for a single person is approximately $21,870. If your income is $40,000, your discretionary income is approximately $18,130 and your payment is about $151 per month.

If you have not paid off the loan after 20 years (undergraduate loans) or 25 years (graduate loans), the remaining balance is forgiven. Under SAVE, forgiveness can come earlier for low-balance borrowers.

The tradeoff: because payments are often not enough to cover accruing interest in the early years, balances can grow before income increases bring payments in line with the actual interest cost. Forgiven amounts may be taxable income under current law.

Side-by-side plan comparison: $40,000 at 5.5%

This table assumes a single borrower with $40,000 in direct federal loans at 5.5% and a starting income of $38,000.

The extended 25-year plan is included for reference. It’s available for borrowers with more than $30,000 in federal debt. Monthly payments are more manageable, but total interest nearly triples compared to the standard 10-year plan.

The IBR numbers assume income grows from $38,000 to roughly $55,000 over 10 years (2% annual growth). The forgiveness amount on IBR depends heavily on balance growth, income trajectory, and plan specifics.

Real-world examples

New graduate choosing between Standard and IBR

A recent graduate with $35,000 in federal loans at 5% starts a nonprofit job earning $34,000. Under Standard 10-year, the monthly payment is about $371. That’s close to 13% of gross monthly income ($2,833), which is tight but manageable if living costs are low.

Under IBR, the payment would be roughly $104 per month (10% of discretionary income above the 150% poverty line). This frees up $267 per month, which matters a lot at $34,000 salary.

However, if this person qualifies for Public Service Loan Forgiveness (PSLF), the math changes again. PSLF forgives the remaining balance after 10 years of qualifying payments in a government or nonprofit job. The optimal strategy becomes paying the minimum on IBR for 10 years and targeting PSLF forgiveness, rather than overpaying to reduce interest.

Couple managing two loans

A couple has two federal loan accounts: one partner with $25,000 at 4.5% and one with $55,000 at 6%. Combined monthly obligation under Standard plans: $259 + $611 = $870. Their combined gross income is $95,000, so IBR would set payments far below the standard amount. Graduating to Standard payments when income allows, while targeting the 6% loan for extra payments, saves the most in interest.

Common mistakes with repayment plans

Choosing Graduated without understanding the total interest cost

Many borrowers pick Graduated because the first payment is smaller, without looking at what that choice costs over 10 years. The calculator’s comparison tab makes this clear: you might pay $2,000 to $5,000 more in interest over the life of the loan in exchange for lower payments in years 1 through 3. Sometimes that tradeoff is worth it. Often, borrowers just didn’t know the total cost before deciding.

Not accounting for income growth in IBR analysis

IBR is income-sensitive, which means your payments rise as your income rises. A payment of $120/month at $32,000 income might become $380/month at $65,000. Projecting IBR based on current income without modeling future income leads to surprises. Use the Multi-Loan tab to model different income growth scenarios.

Missing the refinancing window

If your federal loans carry rates above 5.5% and you have a stable income and good credit history, you may qualify to refinance into a private loan at a lower rate. The window of opportunity is often in the first 3 to 5 years after graduation, when your credit has improved but the loan balance is still large enough for the rate difference to matter significantly.

Refinancing federal loans to private without understanding the consequences

Refinancing federal loans into a private loan permanently removes your access to IBR, PSLF, deferment, and forbearance. If you lose your job or your income drops, you lose all the income-based safety nets that come with federal loans. This tradeoff is often not communicated clearly by private lenders. Only refinance federal loans to private if your career is stable and you have no expectation of needing income-driven repayment.

Ignoring servicer errors

Loan servicers have a documented history of miscategorizing payments, losing paperwork, and failing to process PSLF-qualifying payment counts accurately. If you’re on IBR working toward forgiveness or PSLF, keep meticulous records: download payment confirmations, maintain copies of your income certifications, and re-verify your qualifying payment count annually.

The bottom line

No single repayment plan is right for everyone. The Standard 10-year plan minimizes total interest and is the best choice if your income comfortably covers the payments. Graduated is a reasonable short-term compromise if your income needs to grow before you can afford Standard payments. IBR and SAVE are the right tools if your income is genuinely constrained, if you’re pursuing PSLF, or if you want a safety net against income disruption.

Run the numbers for all three plans before you commit. The calculator exists precisely to make this comparison fast and concrete. Five minutes of analysis now can easily translate to $5,000 to $30,000 in savings over the life of your loans. That’s one of the highest-leverage financial decisions you’ll make in your 20s and 30s.

And then revisit the decision every 2 to 3 years. Income changes, policy changes, and loan balances change. What was the optimal plan at 24 might not be the optimal plan at 30.

Public Service Loan Forgiveness and the IBR calculation

Income-Based Repayment isn’t just for people who can’t afford standard payments. For borrowers working in public service (government, nonprofit, qualifying public health or education roles), IBR combined with Public Service Loan Forgiveness can result in significant tax-free forgiveness after 120 qualifying payments (10 years).

The strategy: enroll in an income-driven plan, make 120 monthly payments while working full-time for a qualifying employer, and the remaining balance is forgiven. For someone with $100,000 in graduate school debt and a $65,000 income in public service, this can mean paying roughly $400-500/month for 10 years (total ~$48,000-$60,000) and having the remaining $60,000-$80,000 forgiven, tax-free.

This is why the comparison between plans can’t be made on total interest cost alone. The right plan depends heavily on your employer and career trajectory.