Montana student loan calculator. Enter your loan balance, interest rate, and repayment term to see your monthly payment and total cost. Montana residents may deduct up to $2,500 in student loan interest on federal taxes; check your state tax return for Montana-specific deductions.

Student Loan Calculator

Enter your loan balance, interest rate, and repayment term to see your monthly payment, total interest, and a month-by-month payoff schedule.

Monthly payment

$341

Detailed results
Total interest paid	$10,932
Total repayment amount	$40,932

What this result means

A $30,000 loan at 6.53% over 10 years costs $341/month. You will pay $10,932 in interest — about 36% of the original balance — for a total repayment of $40,932.

Month-by-month amortization schedule

Every payment broken down into principal and interest, with the remaining balance after each payment.

Month-by-month amortization schedule. 120 rows, first 12 shown.
Month	Payment	Principal	Interest	Remaining balance
1	$341	$178	$163	$29,822
2	$341	$179	$162	$29,643
3	$341	$180	$161	$29,464
4	$341	$181	$160	$29,283
5	$341	$182	$159	$29,101
6	$341	$183	$158	$28,918
7	$341	$184	$157	$28,735
8	$341	$185	$156	$28,550
9	$341	$186	$155	$28,364
10	$341	$187	$154	$28,177
11	$341	$188	$153	$27,990
12	$341	$189	$152	$27,801

How this is calculated

M = P · r(1+r)^n / ((1+r)^n − 1)
where P = loan balance, r = rate / 12, n = term in months
When r = 0: M = P / n

How student loan payments are calculated

Student loan monthly payments use standard amortization: each payment covers that month's interest first, with the remainder reducing principal. The formula is:

M = P × r(1+r)^n / ((1+r)^n − 1)

where P is the loan balance, r is the monthly interest rate (annual rate ÷ 12), and n is the term in months. Early payments are mostly interest; later payments are mostly principal. The 10-year standard plan is the federal default.

Federal vs. private student loans

Federal loans (Direct Subsidized, Direct Unsubsidized, PLUS) carry fixed rates set annually by Congress and offer income-driven repayment (IDR), deferment, forbearance, and forgiveness programs. Private loans are issued by banks and credit unions at fixed or variable rates based on creditworthiness and have none of those protections. This calculator works for both — just enter the correct rate.

Repayment plan options

The federal standard plan (10 years) minimizes total interest. Extended plans (20–25 years) lower the monthly payment significantly but roughly double total interest paid on a typical balance. Income-driven plans (IBR, SAVE, PAYE) cap payments at 5–10% of discretionary income and forgive remaining balances after 20–25 years — but forgiven amounts may be taxable income. Use this calculator to model the standard payment, then compare to your IDR payment on the studentaid.gov loan simulator.

When to consider refinancing

Refinancing federal loans into a private loan can lower your rate if you have strong income and credit, but you permanently give up federal protections (IDR, PSLF eligibility, deferment). Refinancing makes sense if you would not qualify for forgiveness programs and the rate reduction saves meaningful interest over your remaining term.

Assumptions

Standard amortization: fixed monthly payment, interest = balance × (rate/12) each month.
Rate is fixed for the full repayment term.
No grace period, origination fees, or capitalized interest at entry.
Income-driven repayment, PSLF, and deferment options are not modeled — see studentaid.gov for those scenarios.
Tax deductibility of interest not included in payment calculation.

Frequently asked questions

›What is the current federal student loan interest rate?

Federal student loan rates are set each July 1 for the coming academic year based on the 10-year Treasury note auction in May. For 2024–25: Direct Subsidized and Unsubsidized (undergrad) 6.53%, Unsubsidized (grad) 8.08%, PLUS loans 9.08%. Rates are fixed for the life of the loan.

›How is the 10-year standard repayment payment calculated?

Your servicer uses the standard amortization formula: monthly payment = balance × monthly-rate × (1 + monthly-rate)^120 / ((1 + monthly-rate)^120 − 1). At 6.53% on $30,000, that's about $339/month. Each payment covers that month's interest (balance × 6.53%/12) with the remainder reducing the balance.

›What happens to interest while I'm in school?

Subsidized loans: the government pays the interest that accrues during in-school, grace, and deferment periods, so your balance does not grow. Unsubsidized loans: interest accrues from disbursement even while you're in school. If you don't pay it during school, it capitalizes (is added to principal) when repayment begins, increasing your balance and all future interest charges.

›Should I pay off student loans early or invest the difference?

It depends on your loan rate relative to expected investment returns. If your loans are at 4–5%, long-run market returns (~7–8% nominal) likely beat early payoff. At 7%+ rates, paying down loans is a guaranteed return equal to the rate, which becomes more competitive with volatile market returns. The correct answer also depends on your risk tolerance and whether the loan is federal (with protections) or private.

›What is income-driven repayment (IDR) and how does it affect total cost?

IDR plans cap your payment at a percentage of discretionary income (typically 5–10%) regardless of loan balance. Under the SAVE plan, undergraduate borrowers pay 5% of discretionary income; remaining balances are forgiven after 20 years. IDR lowers monthly payments but often increases total interest paid significantly — and forgiven balances may be taxable. IDR is most valuable when your payment-to-income ratio would make standard payments unaffordable, or when you pursue Public Service Loan Forgiveness (PSLF).

›What is Public Service Loan Forgiveness (PSLF)?

PSLF forgives the remaining federal loan balance after 120 qualifying payments (10 years) while working full-time for a qualifying government or non-profit employer. Payments under any IDR plan count. Forgiveness under PSLF is currently tax-free. PSLF is most valuable for borrowers with high balances and lower incomes in qualifying sectors (government, 501(c)(3) non-profits, public hospitals, public schools).

›Can I deduct student loan interest on my taxes?

Yes, up to $2,500 of student loan interest paid per year is deductible as an above-the-line deduction (you don't need to itemize). The deduction phases out at higher income levels: for 2025 it phases out between $75,000–$90,000 (single) and $155,000–$185,000 (MFJ). You receive a Form 1098-E from your servicer showing interest paid.

›What if I miss a student loan payment?

Federal loans have a 270-day delinquency window before default. After 90+ days late, your servicer reports to credit bureaus. At default, the entire balance becomes due, your wages and tax refund can be garnished, and you lose eligibility for IDR and deferment. Federal loans offer deferment (in school, unemployment, economic hardship) and forbearance (up to 3 years) that pause payments without default. Contact your servicer before missing a payment.