Finance
Student Loan Calculator
A student loan payment is M = P·i/(1−(1+i)^−n) — the balance, the monthly rate, and the number of payments. Enter yours for the monthly payment, the total interest, the payoff date, and what interest that built up in school does once it capitalizes.
Your loan
What you owe at the start of repayment
$
The annual rate on the loan
%
Years to repay — the Standard plan is 10
years
In-school interest
Loan type
Interest accrues while you are in school and during the grace period.
Months before repayment where interest can build up
months
Capitalize accrued interest
Add unpaid interest to the balance when repayment begins
Anything above the payment goes straight to principal
$
Monthly payment · 10y
$341.10
$10,932 total interest on $30,000
Principal $30,000Interest $10,93226.7% of every dollar repaid is interest
Monthly payment
$341
Total interest
$10,932
Total repaid
$40,932
Accrued in school
—
Repayment balance
$30,000
Payoff time
10y
Estimate only. Federal rates are fixed by law each year; your actual payment depends on your loan type, servicer and repayment plan.
Try a scenario
No sign-up · Free
The basics
What is a student loan payment?
A student loan is repaid in equal monthly instalments over a fixed term, just like any other amortizing loan. Two features set it apart from a car or personal loan.
M = P·i ÷ (1 − (1 + i)^−n)
One level payment to the end
The payment M is fixed for the life of the loan, but its split shifts — early payments are mostly interest on a large balance, later ones almost all principal. Nothing floats, so the last payment is known the day repayment starts.
$30,000 at 6.53% over 10 years → $341.10 a month
subsidized vs unsubsidized
Interest can start before you do
On an unsubsidized loan, interest accrues while you are in school and in grace, and can be capitalized — added to the balance — when repayment begins. On a subsidized loan the government pays that interest, so your balance is exactly what you borrowed.
2 years 3 months in school on $30,000 adds $4,407.75 before your first payment
Method
How to calculate a student loan payment by hand
Five steps take you from a balance to the two numbers that matter: what you pay each month, and what the loan really costs.
- 1
Add up the interest that accrued in school
On an unsubsidized loan, simple interest builds while you study and through the grace period. A subsidized loan skips this — the government covers it.
$30,000 × 6.53% × 2.25 yr = $4,407.75 accrued - 2
Capitalize it, or keep it separate
If the accrued interest is capitalized it joins the principal P, so you pay interest on it too. If not, it is still owed but never compounds.
$30,000 + $4,407.75 = $34,407.75 repayment balance - 3
Convert the annual rate to a monthly rate
Divide the annual rate by twelve for the periodic rate i, and multiply the term in years by twelve for the number of payments n.
i = 6.53% ÷ 12 = 0.00544167 · n = 10 × 12 = 120 - 4
Apply the level-payment formula
The payment M is the one figure that repays the balance to exactly zero on the last month.
M = P·i ÷ (1 − (1 + i)^−n) = $341.10 - 5
Total the payments, subtract the balance
Multiply the payment by the number of payments for everything you repay, and subtract the repayment balance for the interest.
$341.10 × 120 = $40,932.24 · interest $10,932.24
Worked examples
The same balance over four terms
$30,000 at 6.53%. A longer term buys a smaller payment at a steep price in interest — the total cost of the loan more than doubles from ten years to twenty-five.
| Term | Monthly payment | Total interest | Total repaid |
|---|---|---|---|
| 10 years | $341.10 | $10,932 | $40,932 |
| 15 years | $261.83 | $17,129 | $47,129 |
| 20 years | $224.20 | $23,809 | $53,809 |
| 25 years | $203.12 | $30,937 | $60,937 |
The 25-year payment is $203.12 against $341.10 for the 10-year, but it costs $20,005 more in interest.
Where it shows up
Three questions the payment answers
The monthly figure drives the three decisions borrowers actually face.
the default plan
Standard repayment
The Standard 10-year plan is where most borrowers start. It has the highest payment of the common plans but the lowest total interest, because the balance clears fastest.
$30,000 → $341.10 a month for 10 years
APR, not rate
Refinancing
Refinancing swaps your loan for a new one at a new rate. It is straightforward for private loans and permanent for federal ones, which give up income-driven plans and forgiveness.
A lower rate saves interest — but federal loans lose protections
no penalty
Paying extra
There is no prepayment penalty, so every extra dollar goes to principal. Because interest is front-loaded, overpaying early in the term is worth the most.
$100 extra a month here removes $3,365.27 of interest
Reference
Federal repayment plans
General guidance, not a rate sheet — plan rules change, so check the Department of Education for current terms. Each plan trades a lower payment for more interest or a longer term.
| Plan | Term | Best for | What it means |
|---|---|---|---|
| Standard | 10 years | Paying the least interest | Fixed level payments over ten years. The default, and the cheapest overall for most borrowers. |
| Graduated | 10 years | Low income now, rising later | Payments start low and step up every two years. More interest than Standard for the same term. |
| Extended | Up to 25 years | Large balances, lower payment | Stretches the term to as long as 25 years for a smaller payment — and much more interest. |
| Income-driven (IDR) | 20–25 years | Payment tied to income | Payment is a share of discretionary income; any remaining balance may be forgiven at the end. |
Worth knowing
Six things that decide the cost
None of these are in the headline rate, and each can be worth more than a point of interest.
interest on interest
The capitalization trap
Unpaid interest that capitalizes joins your principal and compounds for the whole term. Paying even part of the accrued interest before it capitalizes stops that snowball.
the government pays
Subsidized beats unsubsidized
A subsidized loan accrues no interest in school, so its balance at repayment is exactly what you borrowed. Take the full subsidized amount before any unsubsidized borrowing.
protections are permanent to lose
Think hard before refinancing federal
Refinancing federal loans into a private loan forfeits income-driven repayment, deferment, forbearance and forgiveness for good. A lower rate rarely justifies losing all of that.
a quarter point off
Autopay discount
Most servicers and lenders shave a fraction of a point off the rate for automatic payments. It costs nothing beyond keeping the account funded, and it is easy to overlook.
front-loaded interest
Overpaying early is worth most
Interest is charged on the balance, which is largest at the start, so an extra payment in year one removes far more interest than the same payment near the end.
six months after school
Mind the grace period
Federal loans give a six-month grace period after you leave school before repayment starts — but on unsubsidized loans interest still accrues through it and can capitalize after.
Quick chart
Payments by balance, rate and term
Pick a balance and read the monthly payment — or the total interest, or everything you repay — at every rate from 3% to 9% across four terms.
Loan balance
Show
Monthly payment on $30,000, by rate and term.
| Rate | 10 years | 15 years | 20 years | 25 years |
|---|---|---|---|---|
| 3.00% | $290 | $207 | $166 | $142 |
| 4.00% | $304 | $222 | $182 | $158 |
| 5.00% | $318 | $237 | $198 | $175 |
| 6.00% | $333 | $253 | $215 | $193 |
| 7.00% | $348 | $270 | $233 | $212 |
| 8.00% | $364 | $287 | $251 | $232 |
| 9.00% | $380 | $304 | $270 | $252 |
Figures are on the balance at repayment and exclude any interest that capitalizes from your time in school. Use the calculator above to fold that in.
How we calculate this
The formula and our assumptions
The payment uses the standard amortizing-loan formula; the student-loan specifics are the in-school interest and whether it capitalizes.
M = P·i ÷ (1 − (1 + i)^−n)
The payment
P is the balance at repayment, i the annual rate divided by twelve, and n the number of monthly payments. When the rate is zero the payment is simply P divided by n.
accrued = balance × rate × years
In-school interest
Interest accruing before repayment is treated as simple interest on an unsubsidized loan, and zero on a subsidized loan. If capitalized it is added to P; if not, it is owed on top but never compounds.
- The rate is fixed for the life of the loan; variable-rate private loans are not modelled.
- In-school interest is simple interest; the tool capitalizes it once, at repayment.
- Payments are equal and monthly (the Standard-style plan); graduated and income-driven schedules differ.
- Extra payments are applied straight to principal in the month they are made.
Where to borrow or refinance
Where the loan lives
Rows are ordered by borrower fit, not by any payout. For most people with federal loans, the servicer that keeps every federal protection comes first — a lower private rate rarely outweighs losing income-driven repayment and forgiveness.
| Where | Examples | Best for | What to know |
|---|---|---|---|
| Federal servicer | MOHELA, Nelnet, Aidvance | Keeping every federal protection | Where federal loans live. Access to income-driven plans, deferment, forbearance and forgiveness — none of which a private loan offers. |
| Private refinance lender | SoFi, Earnest, Credible marketplace | A lower rate on private debt | Can cut the rate on private loans, or on federal loans you are sure you will never need protections on. Refinancing federal loans here is permanent. |
| Credit union / bank | Member and local lenders | Relationship pricing | Sometimes competitive on private refinancing, especially for members, but the market is thinner than the specialist lenders. |
CalculateThis.io is not a lender and does not make credit decisions. Refinancing a federal loan into a private loan permanently forfeits federal protections. When we add lender links they will be marked as sponsored, and we may earn a commission if you apply through one — it does not change the rate you are offered.
Sources
Where the method comes from
- U.S. Department of Education / Federal Student Aid — repayment plans, subsidized vs unsubsidized loans, and interest capitalization.
- Consumer Financial Protection Bureau — student loan repayment and refinancing guidance.
- Standard amortization formula for a fixed-rate, fully amortizing loan.
FAQ
Common questions
On the standard level-payment formula M = P·i ÷ (1 − (1 + i)^−n), where P is the balance at repayment, i is the annual rate ÷ 12, and n is the number of monthly payments. A $30,000 balance at 6.53% over 10 years is $341.10 a month, and you repay $40,932.24 in total — $10,932.24 of it interest. The one wrinkle unique to student loans is interest that built up while you were in school, which can be added to the balance before this formula is applied.
At 6.53% on the Standard 10-year plan it is $341.10 a month, with $10,932.24 of total interest. Stretch the term to 25 years and the payment falls to $203.12 but the interest climbs to $30,937.47 — more than 2.8 times as much. The quick chart on this page gives the payment for every balance, rate and term.
On a subsidized federal loan the government pays the interest while you are in school and during the six-month grace period, so nothing accrues and your balance at repayment is exactly what you borrowed. On an unsubsidized loan interest accrues the whole time. On $30,000 at 6.53%, 2 years 3 months in school adds $4,407.75 of interest before you make a single payment — money a subsidized borrower never owes.
Capitalization is when unpaid interest is added to your principal, so you then pay interest on that interest. On the $30,000 example, the $4,407.75 that accrued in school pushes the balance to $34,407.75 if capitalized — lifting the payment to $391.22 and the total interest to $12,538.46. Keep it separate instead and the payment stays $341.10, because the interest never compounds. Paying the accrued interest before it capitalizes, even a little, avoids the snowball.
Refinancing can lower your rate, but there is a sharp catch for federal loans: refinancing them into a private loan permanently forfeits federal protections — income-driven repayment, deferment and forbearance, and loan forgiveness programs. For private loans, or for federal loans you are certain you will never need those protections on, a lower rate saves real interest. Compare the APR, not the rate, and never refinance federal debt without understanding exactly what you give up.
A lot, because there is no prepayment penalty on federal or most private student loans — every extra dollar goes straight to principal. On the $30,000 example at 6.53%, paying $100 extra a month clears the loan in 7 years 2 months instead of 10 years and removes $3,365.27 of interest. Tell your servicer to apply the extra to principal, not to advance your due date.
The Standard plan is fixed level payments over ten years, and it is the default for federal loans. It carries the highest monthly payment of the common plans but the lowest total interest, because the balance is cleared fastest. On $30,000 at 6.53% that is $341.10 a month. Graduated, Extended and income-driven plans all lower the payment in exchange for more interest or a longer term.
Keep going
Related calculators
Keep reading
Further reading
Calculator
Gross vs Net: The Difference, With Dollar Examples
Gross is the total before deductions; net is what is left after deductions are subtracted. This guide explains gross vs net for pay, income, and profit with worked dollar examples and a quick comparison table.
Ugo Charles
Calculator
How to Write a Check: A Step-by-Step Guide
Writing a check takes six fields: the date, the payee, the amount in numbers, the amount in words, an optional memo, and your signature. This guide walks every field with one worked example and shows exactly how to write the cents.
Ugo Charles
Finance
The Compound Interest Formula: A = P(1 + r/n)^(nt), Explained
The compound interest formula is A = P(1 + r/n)ⁿᵗ, where P is the starting principal, r is the annual rate as a decimal, n is the number of times interest compounds per year, t is the number of years, and A is the final amount. This guide defines each variable, works a full example, and shows how compounding frequency changes the result.
Ugo Charles
Written by
UC
Author
Ugo CharlesBuilt and fact-checked against our editorial standards · Last updated June 2026
Did this solve your problem?