Student Loan Calculator

What Is a Student Loan?

Two systems share the name. Federal student loans are made by the U.S. Department of Education under the Direct Loan Program, and their terms are written into federal regulation rather than negotiated. Private student loans are ordinary consumer credit from a bank, credit union or online lender, priced on creditworthiness and governed by the contract you signed. Both amortize identically once repayment begins, which is why one calculator serves both — and almost nothing else about them matches.

Federal vs. Private Loans

The federal side carries machinery that exists because regulation requires it rather than because a lender chose to offer it: income-driven repayment, deferment and forbearance, and cancellation programs, all defined in title 34, part 685 of the Code of Federal Regulations rather than in a contract that can be rewritten. The private side offers the one thing federal lending cannot — a rate underwritten to the borrower, which for strong credit or a creditworthy cosigner can come in below the statutory rate.

• Rate. Federal rates are fixed by law for each academic year and identical for every borrower in a category. Private rates are underwritten individually and may be variable.
• Fees. A Direct Subsidized or Unsubsidized loan first disbursed on or after July 1, 2010 carries a loan fee capped at 1% of the principal; a Direct PLUS loan carries a fee of four percent. The fee is deducted from the proceeds, so the school receives less than the balance you owe.
• Repayment menu. Federal borrowers can switch plans; a private loan runs on the schedule set out in its promissory note.
• Relief. Deferment, forbearance and income-driven plans are federal features. A private lender may offer a hardship program, or nothing at all.

Enter one loan at a time. A borrower carrying an undergraduate loan at one rate and a graduate loan at a higher one has two different answers, and averaging the two rates hides the very difference that decides where a spare dollar should go.

What the Standard Repayment Plan Is

The federal default, and the reason this page opens on ten years. Under 34 CFR 685.208, a borrower whose Direct Loans were made before July 1, 2026 must repay "in full within ten years from the date the loan entered repayment by making fixed monthly payments," and those payments are "at least $50 per month, except that a borrower's final payment may be less than $50."

Loans made on or after July 1, 2026 fall under a different rule in the same section: a tiered standard plan whose term is set by how much is owed when repayment begins. The four tiers map exactly onto the four buttons in the form.

A Direct Consolidation Loan is a third case with its own ladder: 10 years below $7,500, then 12, 15, 20 and 25 years as the consolidated total climbs, reaching 30 years at $60,000 and above. Two of those terms, 12 and 30 years, are not among the four this calculator offers — the note under Limits says what to do about them.

How Do You Calculate a Student Loan Payment?

One equation does all of it. The payment is the figure that, charged every month for the whole term, exactly clears the balance plus the interest that accrues along the way — the standard amortized-loan payment, identical to the one behind a mortgage or a car note.

The Student Loan Formula, Written Out

Two conversions, then a single division:

r = annual rate ÷ 1200        (5.5% → 5.5 ÷ 1200 = 0.004583333)
n = years × 12                (10 years → 120 months)

Payment = P × r ÷ (1 − (1 + r)⁻ⁿ)

P              = the balance you owe today
Total repaid   = Payment × n
Total interest = (Payment × n) − P

The denominator is where the work happens. (1 + r)⁻ⁿ is what one dollar due n months from now is worth today; subtract it from 1 and you have the present-value factor of an n-month annuity, a finite geometric series in compressed form. Divide the first month's interest, P × r, by that factor and the level payment falls out. Notice what the equation never mentions: your income, your degree, your credit score, your family size. Only the three numbers in the form.

At a rate of exactly 0% the denominator would be zero, so the code substitutes:

Payment = P ÷ n

That branch is not decoration, but reaching it takes a typed zero. Enter 0 as the rate and a $30,000 balance over ten years returns $250/month with $0 of interest, which is what a genuinely interest-free loan costs. Leaving the rate box empty does something else entirely: the page refuses to compute and asks for the field by name, so an empty box can no longer masquerade as a 0% loan.

Step by Step

The default worked example — $30,000 at 5.5% over 10 years — one line at a time:

• Monthly rate: 5.5 ÷ 1200 = 0.004583333.
• Months: 10 × 12 = 120.
• Discount factor: 1.004583333 raised to the −120th power = 0.577675.
• Annuity factor: 1 − 0.577675 = 0.422325.
• First month's interest: $30,000 × 0.004583333 = $137.50.
• Payment: $137.50 ÷ 0.422325 = $325.58.
• Total repaid: the unrounded payment × 120 = $39,069.46.
• Total interest: $39,069.46 − $30,000 = $9,069.46.
• Interest as a share of principal: $9,069.46 ÷ $30,000 = 30.2%.

Carry the discount factor to six decimals. Round it to three — 0.578 in place of 0.577675 — and the payment comes out at $325.83, a quarter high, which compounds to $39,099.53 over the term and puts the interest figure $30 out. Step seven hides the other trap: multiply the rounded $325.58 by 120 and the answer is $39,069.60, not the $39,069.46 the panel prints. Every total on this page is built from the unrounded payment and rounded once, at the end.

Worked Example: $30,000 at 5.5% Over 10 Years

Both number fields arrive empty, so this run needs two figures typed and the term left where it starts:

Inputs: $30,000 balance · 5.5% rate · 10 years (standard)

$325.58/month

Below the headline the panel prints three more lines, in this order: "$30,000 at 5.5% over 10 years (standard amortization)"; then "Total repaid: $39,069.46 — interest is $9,069.46 (30.2% of principal)"; then a reminder that federal income-driven plans compute differently, from income rather than from the balance.

The $9,069.46 is what a decade of borrowing costs at that rate. It is not a fee and not a penalty — it is 5.5% charged month after month on a balance that starts at $30,000 and finishes at zero, which works out to roughly ten years of interest on half the principal. The back-of-envelope check confirms the size: $30,000 × 5.5% × 10 ÷ 2 = $8,250, about $800 under the true figure, because a real balance falls more slowly than a straight line.

Using This Student Loan Calculator Online

Three fields and one button. The term selector arrives already set to "10 years (standard)", but the two number fields arrive blank, so the result panel shows a dash until you press Calculate — nothing is waiting when the page loads, and nothing recalculates as you type.

• Loan Balance: what you owe now, not what you originally borrowed. Interest that capitalized during school or a deferment is part of the balance, and the payment is computed on the balance.
• Interest Rate: the annual rate as a percentage — 5.5, not 0.055. Anything from 0 to 30 is accepted.
• Repayment Term: four buttons — 10, 15, 20 and 25 years — with 10 already selected.
• Calculate runs the formula; Reset empties the fields and returns the panel to its dash; Copy result puts all four output lines on the clipboard as plain text.

Two gates stand between the form and an answer. The page checks first that both number fields hold something. Press Calculate with the balance empty and the panel names the field — “Enter a value for Loan Balance.” — rather than reading the blank as a zero; leave both fields empty and it lists both. Past that gate the formula applies its own two checks: a zero or negative balance produces “Enter the loan amount”, and a rate above 30 or below zero produces “Enter the interest rate (0–30%)”. Every one of those messages replaces the result with an amber “Check your inputs” notice. Neither field carries a browser-enforced minimum or maximum — the form is rendered without validation attributes, so those checks are the entire gate, and a balance of $12.50 or a rate of 29.999 passes through without complaint.

The arithmetic itself runs in your browser, in a small module fetched only when a calculation is needed, so the balance and rate you type are not sent anywhere in order to work out the answer. The page around it carries analytics and advertising tags in the ordinary way, so that is a statement about your numbers, not a claim that the visit is invisible.

How to Read Your Result

The panel returns four segments in the same order every time: the payment as the big readout, a restatement of what was run, the totals line, and the standing note about income-driven plans. The totals line carries most of the information. Four things are easy to misread — three of them about that line, one about how the payment beside it divides.

The Interest Percentage, and What Counts as High

The figure that closes the totals line — “30.2% of principal” on the default run — is lifetime interest divided by the balance. That is a proportion rather than a dollar amount, which is what puts loans of very different sizes on one scale.

• Under 40%: ten years at any ordinary rate. The default run — $30,000 at 5.5% over ten years — sits at 30.2%, and a ten-year term does not reach 40% until the rate passes about 7.1%.
• 40% to 70%: fifteen years between roughly 4.8% and 7.8%, twenty years between roughly 3.6% and 5.9%, or ten years above about 7.1%. $30,000 at 5.5% over fifteen years lands at 47.1%; over twenty years it is 65.1%.
• 70% to 100%: twenty-five years between roughly 4.7% and 6.4%, twenty years between roughly 5.9% and 8%, or fifteen years above about 7.8%. That same balance and rate over twenty-five years reach 84.2% — $25,267.87 of interest.
• Over 100%: the loan costs more in interest than it did in principal — twenty-five years above about 6.4%, or twenty years above about 8%. $50,000 at 7% over twenty-five years returns 112.0%, or $56,016.88.

Only two things move that percentage. Rate and term set it; the balance cancels out, which is why $10,000 and $100,000 at 8% over ten years both print 45.6% — one owes $4,559.31 of interest and the other $45,593.11, and the proportion is identical.

Where the First Payment Goes

The payment is level; its composition is not. Month one on the default run is charged $30,000 × 5.5% ÷ 12 = $137.50 of interest, leaving $188.08 of the $325.58 to reduce the balance. Interest is 42.2% of that first payment and a smaller share of every payment after it.

Stretch the identical loan to twenty-five years and month one's interest does not change — it depends only on the balance and the rate, and neither has moved. The payment does: $184.23, of which the same $137.50 is interest and just $46.73 is principal. Three quarters of an early payment on that term, 74.6% of it, buys nothing but time.

Which is why the crossover point matters. On the ten-year schedule, principal already exceeds interest in the very first payment. On the twenty-five-year schedule that does not happen until month 150 — twelve and a half years in, exactly the halfway mark of the term, with $19,951.82 of the original $30,000 still outstanding.

Why the Payment Times the Months Is Not the Total

Multiply the displayed payment by the number of months and the answer will not match the displayed total. $325.58 × 120 comes to $39,069.60; the panel says $39,069.46. Those fourteen cents are the payment's own rounding — the exact figure is $325.578833… — and every total is computed from that before anything is rounded for display.

The readout also drops trailing zeros. Run $20,000 at 6.5% over ten years and it prints “$227.1/month”, meaning $227.10; a rate of 0 prints “$250/month”, meaning $250.00. Any real schedule has to absorb that rounding somewhere, which is why the last payment on an amortization table is almost never identical to the 119 before it.

The Interest Figure and Your Tax Return

The tool reports a lifetime total; the tax code works one year at a time. IRS Topic no. 456 sets the student loan interest deduction at "the lesser of $2,500 or the amount of interest you actually paid during the year," and it is claimed as an adjustment to income — in the agency's words, "you don't need to itemize your deductions" to take it. The deduction phases out above a modified adjusted gross income threshold that is reset annually, so look up the current one rather than reusing last year's.

Against the default run, the first twelve months of the ten-year schedule carry $1,592.23 of interest, under the cap, so all of it would be deductible for a borrower inside the income limits. Stretching that loan to twenty-five years raises the first year only to $1,635.65 — still short. The $2,500 ceiling starts to bind on much larger balances: $100,000 at 8% over twenty-five years accrues $7,952.69 in its first year, roughly two thirds of which no deduction reaches.

Student Loan Chart: Payment per $10,000 Borrowed

Amortization is linear in the balance, so a single table covers every loan. Find the row for your rate, read across to your term, then multiply by your balance in units of $10,000 — a $25,000 loan is 2.5 times the row, a $47,500 loan 4.75 times it.

Monthly Payment per $10,000 Borrowed

The multiplication is exact rather than approximate. $111.02 × 2.5 = $277.55, and entering $25,000 at 6% over ten years returns $277.55. Totals scale on the same rule: that loan repays $33,306.15 including $8,306.15 of interest, precisely 2.5 times the $13,322.46 and $3,322.46 a $10,000 loan produces at the same rate and term.

Read down a column and the price of rate appears; read across a row and the price of time does. Four points of rate adds $20.08 a month per $10,000 over ten years. Fifteen extra years at 6% takes $46.59 a month off that same $10,000 — and charges $9,329.04 of interest for the privilege instead of $3,322.46, close to three times as much.

What Each Term Costs on $30,000 at 5.5%

One balance, one rate, the four terms on the menu, every figure taken straight from the panel:

Treat it as a price list for breathing room. Moving from ten years to twenty lowers the payment by $119.21 and raises lifetime interest by $10,458.43 — about $88 of extra interest for every dollar the monthly figure drops. Going the whole way to twenty-five saves $141.35 a month and costs $16,198.41, a worse exchange rate at roughly $115 per dollar.

Those differences are computed from the unrounded figures, so subtracting two displayed totals can land a cent or so away from the numbers quoted here. The final column is the honest headline: at twenty-five years the interest alone comes to more than four fifths of what was borrowed in the first place.

Student Loan Examples

Three runs answering three different questions. Every figure below came out of this calculator, or — where the text says so — out of the same monthly recursion worked through by hand.

One Rate, Four Balances, the Term the Law Assigns

The tiered standard plan sets the term from the balance rather than letting the borrower choose. Holding the rate at 6.5% and giving each balance its statutory term prices that ladder:

The payment column rises far more slowly than the balance: $120,000 is six times $20,000, but the payment is only 3.6 times larger, because each tier hands the extra borrowing more time. The interest column is where that time went — six times the balance, close to seventeen times the interest, and the largest loan is the only one of the four that repays more in interest than it ever borrowed.

Adding $50 a Month to a $30,000 Loan

This calculator prices a fixed schedule and has no field for extra payments. The schedule it prices is the baseline, though, and the same month-by-month recursion carries the question the rest of the way.

The default run clears $30,000 at 5.5% in 120 payments of $325.58, costing $9,069.46 in interest. Paying $375.58 instead clears it in 100 payments — twenty months early — for $7,441.47, a saving of $1,627.99. Another fifty dollars on top of that, $425.58 a month, finishes in 86 payments and $6,316.14. Because the scheduled payment already covers the month's interest, the extra fifty goes against principal, and that principal stops accruing interest for the rest of the term, which is why the saving so far exceeds the extra dollars themselves.

Federal rules make the experiment cheap. 34 CFR 685.211(a)(2) is unambiguous: "A borrower may prepay all or part of a loan at any time without penalty." The same section then sets a trap — where a prepayment "equals or exceeds the monthly repayment amount," the Department "advances the due date of the next payment unless the borrower requests otherwise." Send $650 one month without saying anything and you may simply not owe a payment the next, which is the opposite of what someone paying extra intends.

So the instruction to give is narrower than the folklore suggests. Extra money cannot be aimed straight at principal on request. Under 685.211(a)(1)(i) a payment goes to accrued charges and collection costs first, then to outstanding interest, and only then to outstanding principal; borrowers repaying under IBR or the Repayment Assistance Plan get the different order set out in (a)(1)(ii) — accrued interest, then collection costs and late charges, then loan principal. Neither sequence is the borrower's to choose, and principal is last in both. What you can ask for is that additional amounts not advance the due date — that request is written into the regulation, and it is the one worth making.

To reproduce those timelines on this site, put the balance, the rate and the higher payment into the by-payment mode of the Credit Card Payoff Calculator.

For $375.58 against $30,000 at 5.5% it returns "100 months (8y 4m)", matching the count above. Its interest line is prefixed with ≈ because it assumes a full final payment; here the hundredth payment is only $259.16, which is why the exact interest is $7,441.47 rather than the $7,558 that tool prints.

What One Percentage Point Is Worth on $40,000

Same balance, same ten-year term, one point of difference in the rate. At 7% the payment is $464.43 and lifetime interest $15,732.07. At 6% they are $444.08 and $13,289.84. The point is worth $20.35 a month and $2,442.23 across the decade — 6.1% of the amount borrowed, for a change of one digit.

That is the honest size of the refinancing prize, and it is why the decision is never only about the rate. Refinancing federal debt into a private loan is irreversible, and what it costs sits on the other side of the ledger: access to the five income-driven plans, deferment and forbearance, and any cancellation program those loans currently qualify for. None of it survives the new promissory note.

Whether a particular offer clears its own costs is a break-even question, which is the job of the Refinance Calculator.

The sequence that respects both sides: use the federal features while the loans are still federal, refinance only debt that has no federal features to lose, and leave alone anything on a realistic path to cancellation.

Limits: When This Does Not Apply

The calculator is exact inside its scope and silent outside it. Several kinds of borrower will find that the figure here is not the figure they end up paying.

Income-Driven Plans Are Not This Math

34 CFR 685.209 opens by saying it outright: income-driven repayment plans “base the borrower's monthly payment amount on the borrower's income and family size.” Five plans qualify — REPAYE, also called SAVE; IBR; PAYE; ICR; and the Repayment Assistance Plan. IBR sets its applicable amount at 15% of the income above 150% of the poverty guideline for the household, or 10% for a new borrower. The Repayment Assistance Plan works from bands of adjusted gross income instead: a flat base payment of $120 where AGI is $10,000 or less, then 1% of AGI in the band just above that, rising a point per $10,000 of income to 10% above $100,000.

No combination of balance, rate and term reproduces those figures, because none of this tool's inputs is your income. One further wrinkle from the same section is worth knowing before planning around a plan: only Direct Loans made before July 1, 2026 may be repaid under PAYE, IBR or ICR.

What the Calculator Does Not Model

Each of the following changes a real repayment, and none of them is an input here:

• Capitalization. Unpaid accrued interest can be added to the principal — 34 CFR 685.202(b) names the practice — so a balance that grew during school or a deferment is larger than the sum disbursed. Enter today's balance, never the original.
• Loan fees. They come out of the proceeds at disbursement, so the fee is already inside the balance rather than a cost still to come.
• Deferment and forbearance. Federal regulation excludes those periods from the repayment term, and interest generally keeps accruing on unsubsidized debt. A paused loan finishes later and costs more than any row on this page.
• Variable rates. A private loan tied to an index moves its payment or its term as the index moves; this model holds one rate for the entire run.
• Daily accrual. The formula charges one twelfth of the annual rate each month, whether that month has 28 days or 31. Any lender that accrues by the day will differ from this schedule by small amounts month to month.
• The $50 floor. Federal plans require at least $50 a month; this tool imposes no minimum at all. $5,000 at 5% over twenty-five years prints $29.23/month, a payment no federal plan would permit — at the $50 minimum that balance clears in 130 months rather than 300.

Two genuine federal terms are also missing from the menu. A Direct Consolidation Loan can run 12 years or 30, and neither is one of the four buttons.

For those, or for a private loan on any other schedule, the same amortization with a free-form term is in the Loan Calculator.

One misuse deserves its own warning. The 15-, 20- and 25-year buttons are not options on an unconsolidated federal loan made before July 1, 2026 — that borrower's standard plan is ten years, full stop. Those longer terms model consolidation, the tiered plan for newer loans, an extended plan, or a private loan. Work out which of them describes your debt before treating a lower payment as a choice you actually have.