Best Student Loan Calculator
A student loan payment is easy to quote and easy to get wrong. Quote it on the amount you borrowed and you miss the interest that piled up during the grace period. Ignore the origination fee and you understate the true cost. Compare a refinance offer on rate alone and you can miss that it costs more after fees. The student loan calculator below handles all three: it capitalizes grace period interest correctly (and charges exactly zero for subsidized federal loans), prices fees into a true cost verdict, tests extra payments, and sets a refinance or second offer side by side against your current loan.
The worked example used throughout is a $30,000 Federal Direct Unsubsidized loan at 6.5% APR over 10 years, with a 6 month grace period, a $55,000 starting salary, a 1% origination fee, a 5% comparison offer, and $100 a month in extra payments. Every figure quoted below is what the tool returns for those inputs. Rates and plan rules change, so for current federal rates check Federal Student Aid interest rates before you borrow, and treat this tool as a planning model, not a servicer statement.
Estimates for planning only, not a servicer statement or financial advice. The income driven line is a rough scale check (about 10% of gross salary). Confirm plan payments, rates and forgiveness rules with your servicer or at studentaid.gov.
Quick Answer
How this student loan calculator works, in order
It runs four steps, and the order is the point. Most simple tools jump straight to step three on the amount borrowed, which understates everything that follows.
Grace period interest. Simple interest accrues while repayment has not started: amount x APR x months / 12. On $30,000 at 6.5% for 6 months that is $975.00. Federal Direct Subsidized loans are charged $0 here, because the government pays the interest during grace on that loan type, a distinction Federal Student Aid draws between subsidized and unsubsidized loans.
Capitalization. The grace interest is added to the balance. Repayment starts on $30,975.00, not $30,000. From here on you pay interest on the interest, which is why six quiet months cost far more than $975 over a 10 year term.
Amortization. The monthly payment spreads that balance evenly over the term at the loan rate. The formula box below gives the exact equation the tool runs.
True cost and comparisons. Total interest is total paid minus the amount borrowed, then the origination fee is added for the true cost figure. Any comparison offer is run through the same steps on the same starting balance, fees included, so the verdict compares like with like.
Worked example: $30,000 unsubsidized at 6.5%
The calculator is pre-filled with this case. Every figure below is its output for those inputs, checked against a hand amortization.
| Figure | Value |
|---|---|
| Grace period interest (6 months, capitalized) | $975.00 |
| Balance when repayment starts | $30,975.00 |
| Monthly payment, 10 years | $351.71 |
| Total paid over the term | $42,205.78 |
| Total interest | $12,205.78 |
| Origination fee at 1% | $300.00 |
| True cost (interest + fee) | $12,505.78 |
| Affordability on a $55,000 salary | 7.7% of income |
| Rough income driven estimate | About $458/month |
| With an extra $100/month | Paid off in 86 months, saving $3,380.45, cutting 34 months |
| Comparison offer at 5%, same term, no fee | $328.54/month, saving $3,081.23 in true cost after fees |
Two comparisons sharpen the picture. Switch the loan type to subsidized with the same numbers and grace interest drops to $0: the payment falls to $340.64 and total interest to $10,877.27, a $1,328.51 difference created entirely by who pays for six months. And if you want a benchmark for what borrowers typically pay, the average student loan payment calculator puts this payment in national context.
The term trade off, priced
A longer term always lowers the payment and always raises the interest. Here is the worked example balance ($30,975.00 at 6.5%) at four terms, all from this tool.
Going from 10 to 20 years buys $120.77 a month of breathing room and costs an extra $13,220.13 in interest. That can still be the right move on a tight first salary, provided the freed cash goes somewhere useful and you revisit overpaying once pay rises. Federal borrowers also have plan choices beyond a single fixed term: Federal Student Aid repayment plans include graduated and income driven options that this fixed payment model does not replicate. If clearing this debt entirely is the goal, a debt free date calculator shows the calendar effect of extra payments across all your debts together, and an accelerated payment calculator tests bigger one off overpayments.
Federal loans: what you get
- Fixed rates set by law, no credit check for Direct Loans.
- Income driven plans, deferment and forbearance when income drops.
- Access to forgiveness programs, including public service routes.
- Grace interest covered for you on subsidized loans.
Private loans: what to watch
- Rates priced on credit: excellent credit can beat federal rates, weak credit costs far more.
- Far fewer hardship options, and no federal forgiveness.
- Refinancing into private is one way: the federal protections do not come back.
- Fees vary by lender, which is why the comparison prices them in.
What competing calculators miss
The top ranking student loan tools are clean and fast, and nearly all of them stop at amount, rate and term. That leaves the three most expensive details of a real loan unmodeled.
Winning move 1: grace interest, with the subsidized exception done right. Basic tools either ignore the grace period or charge interest on every loan type. Both are wrong, in opposite directions. This tool charges simple interest during grace on unsubsidized, PLUS, consolidation and private loans, and exactly zero on subsidized federal loans, then capitalizes the result before amortizing.
Winning move 2: fees in the verdict, not in a footnote. A 5% offer with a fee can cost more than a 5.25% offer without one. The comparison here produces a true cost verdict after fees ($3,081.23 saved in the worked example), so a headline rate cannot win on a technicality. According to the CFPB guide to repaying student debt, comparing total cost rather than rate alone is the habit that protects borrowers at exactly this decision point.
Winning move 3: affordability and extra payments in the same run. Competitors make you open a second tool to test overpaying and a third to judge affordability. Here one calculation returns the payment, the salary share with a plain verdict, the rough income driven figure, and the month and dollar payoff from extra payments ($100 a month: 86 months, $3,380.45 saved). One honest limit: the income driven line is a scale check at about 10% of gross pay, not the discretionary income formula the federal plans actually use. The tool labels it rough, and so does this page.
Frequently asked questions
The calculator first works out the balance when repayment starts: your loan amount plus any grace period interest. It then applies the standard amortization formula, payment = P x r(1+r)^n / ((1+r)^n - 1), where P is that balance, r is the APR divided by 12, and n is the term in months. For $30,000 at 6.5% over 10 years with 6 months of grace on an unsubsidized loan, the balance is $30,975.00 and the payment is $351.71.
On most loan types, interest keeps accruing while you are not yet paying. This tool charges simple interest for the grace months (amount x APR x months / 12) and adds it to the balance, which is called capitalization. Six months on $30,000 at 6.5% adds $975.00. Federal Direct Subsidized loans are the exception: the government covers that interest, so the calculator adds exactly $0 for that loan type.
If you enter a starting salary, the tool compares the annual loan payments with that salary. In the worked example, $351.71 a month is $4,220.52 a year, which is 7.7% of a $55,000 salary, and the verdict calls that comfortably manageable. Above 15% the verdict turns cautious, and above 20% it flags the payment as high and points federal borrowers toward income driven plans. These are planning guides, not lending rules.
It is deliberately rough: the tool estimates about 10% of your gross salary divided by 12, which is $458 a month on a $55,000 salary. Real income driven payments are based on discretionary income, family size and the current federal plan rules, so your servicer or the official Loan Simulator will give a different, more precise figure. Treat this line as a scale check, never as a quote.
Only with your eyes open. The comparison in this tool prices the offer honestly, fees included: a 5% offer on the worked example cuts the payment to $328.54 and saves $3,081.23 in true cost after the 1% fee on the original loan. But refinancing federal loans into a private loan permanently gives up income driven plans, deferment, forbearance and forgiveness programs. A lower rate is a bad trade if you later need any of those protections.
In the worked example, adding $100 a month pays the loan off in 86 months instead of 120, cutting 34 months and saving $3,380.45 in interest. Extra money goes to principal, so each month the interest charge is computed on a smaller balance. The saving grows the earlier you start, because early payments are the most interest heavy.
Enter the fee percentage from your loan disclosure. Federal Direct Loans charge a loan fee that is deducted from each disbursement, and private lenders may charge an origination fee of their own. The tool prices the fee into a true cost figure (interest plus fee) so two offers with different fees can be compared fairly. Leave it at 0 only if your disclosure really shows no fee.
It lowers the payment and raises the total interest, every time. On the worked example balance, stretching from 10 to 20 years drops the payment from $351.71 to $230.94 but lifts total interest from $12,205.78 to $25,425.91. A longer term can still be the right call if cash flow is tight now and you genuinely plan to overpay later. It is a poor call if the lower payment just becomes the permanent payment.
Yes, as loan types. Pick Parent PLUS or Federal Consolidation in the loan type list and the same math runs: grace interest accrues (neither type is subsidized), the balance capitalizes, and the payment amortizes over your chosen term. What it cannot do is blend several separate loans at different rates into one figure. For that, run each loan separately and add the payments.
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References
- Federal Student Aid, "Interest Rates and Fees for Federal Student Loans" - how federal rates are set and the loan fee deducted from Direct Loan disbursements. Federal Student Aid: Interest Rates and Fees. Accessed October 2026.
- Federal Student Aid, "Subsidized and Unsubsidized Loans" - the distinction behind the grace interest rule: the government pays interest on subsidized loans during grace. Federal Student Aid: Subsidized and Unsubsidized Loans. Accessed October 2026.
- Federal Student Aid, "Repayment Plans" - the standard, graduated and extended plans this fixed payment model sits alongside. Federal Student Aid: Repayment Plans. Accessed October 2026.
- Federal Student Aid, "Income-Driven Repayment Plans" - how real IDR payments are based on discretionary income and family size, and why the estimate in this tool is labelled rough. Federal Student Aid: Income-Driven Repayment. Accessed October 2026.
- Federal Student Aid, "Federal Student Loans" overview - loan types, eligibility and borrowing limits for Direct, PLUS and consolidation loans. Federal Student Aid: Types of Loans. Accessed October 2026.
- Federal Student Aid, "Consolidate Your Federal Student Loans" - what consolidation does to rates, terms and plan eligibility. Federal Student Aid: Loan Consolidation. Accessed October 2026.
- Federal Student Aid, "Loan Simulator" - the official estimator for plan specific payments, used to cross check the rough figures here. Federal Student Aid: Loan Simulator. Accessed October 2026.
- Consumer Financial Protection Bureau, "Paying for College" - the CFPB hub for comparing offers, understanding aid letters and planning borrowing. CFPB: Paying for College. Accessed October 2026.
- Consumer Financial Protection Bureau, "Repay Student Debt" - guidance on repayment options, servicer problems and what to do when payments are unaffordable. CFPB: Repay Student Debt. Accessed October 2026.
- Internal Revenue Service, "Topic No. 456, Student Loan Interest Deduction" - the deduction for student loan interest and its limits. IRS: Student Loan Interest Deduction. Accessed October 2026.
- Internal Revenue Service, "Publication 970, Tax Benefits for Education" - the full education tax benefits reference, including interest deduction phase outs. IRS: Publication 970. Accessed October 2026.