— Loans & Debt
Student Loan Calculator
See how interest builds while you study, how much capitalizes onto your balance at graduation, and what the loan really costs once repayment begins.
Monthly payment
$422.99
- Total interest
- $20,758.57
- Total amount repaid
- $50,758.57
- Principal at repayment start
- $38,100
- Interest accrued in school
- $8,100
- Cost of being unsubsidized
- $10,791.19
— Two-phase schedule
| Year | Phase | Interest | Principal | Balance |
|---|---|---|---|---|
| Year 1 | In school | $1,800 | $0 | $31,800 |
| Year 2 | In school | $1,800 | $0 | $33,600 |
| Year 3 | In school | $1,800 | $0 | $35,400 |
| Year 4 | In school | $1,800 | $0 | $37,200 |
| Year 5 | In school | $900 | $0 | $38,100 |
| Year 6 | Repayment | $2,207.99 | $2,867.87 | $35,232.13 |
| Year 7 | Repayment | $2,031.1 | $3,044.76 | $32,187.37 |
| Year 8 | Repayment | $1,843.31 | $3,232.55 | $28,954.82 |
| Year 9 | Repayment | $1,643.93 | $3,431.93 | $25,522.9 |
| Year 10 | Repayment | $1,432.26 | $3,643.6 | $21,879.3 |
| Year 11 | Repayment | $1,207.53 | $3,868.33 | $18,010.97 |
| Year 12 | Repayment | $968.94 | $4,106.92 | $13,904.05 |
| Year 13 | Repayment | $715.63 | $4,360.22 | $9,543.82 |
| Year 14 | Repayment | $446.7 | $4,629.15 | $4,914.67 |
| Year 15 | Repayment | $161.19 | $4,914.67 | $0 |
— Balance over time
Download— How it works
During deferment an unsubsidized balance accrues simple interest; it capitalizes at repayment start to set the new principal, then a standard EMI runs over the repayment term.
Interest starts before your first payment
A student loan is unusual: there is a long gap between borrowing the money and making your first payment. You take it out at the start of study, but repayment does not begin until after you graduate and a grace period passes. On most loans, interest does not wait — it accrues through that whole in-school and grace window. By the time repayment begins, you can owe noticeably more than you borrowed, which is why the “principal at repayment start” is the number to watch.
This calculator models that two-phase life explicitly: an accrual phase while you study, then a repayment phase afterwards. The balance chart rises during the first and falls during the second — a shape unique to student debt.
Worked example — $30,000 at 6%, 4 years in school plus a 6-month grace, unsubsidized and capitalizing: Interest accrues at $150/month for 54 months ≈ $8,100. That capitalizes, so repayment starts on about $38,100 — and the 10-year payment is set on that larger figure, not the $30,000 you borrowed.
Subsidized vs unsubsidized, and capitalization
Whether interest accrues to you during study depends on the loan type. On a subsidized loan the government pays the interest while you are enrolled, so repayment begins on exactly what you borrowed. On an unsubsidized loan that interest is yours, and at repayment start it usually capitalizes — it is added to the principal, so from then on you pay interest on the interest. The calculator shows the gap between the two as the “cost of being unsubsidized”.
If you can afford to pay the accruing interest while still in school, you avoid capitalization entirely: the principal stays at what you borrowed and the long-run saving is larger than the small payments suggest. Switch the “accrued interest” option to compare.
A note on income-driven repayment
This tool models a standard, fixed-payment plan — the same monthly amount over the term. It does not model income-driven repayment (IDR) plans, where payments are a percentage of your discretionary income, can change each year, and may end in forgiveness. Those plans can lower monthly payments substantially but often increase total interest, and their maths depends on income and family-size rules that vary by programme and country.
If you are on or considering an IDR plan, treat the figures here as the standard-plan baseline to compare against, not a forecast of your IDR payments.
— Reader questions
Why do I owe more than I borrowed when repayment starts?
On an unsubsidized loan, interest accrues during the years you are in school and the grace period that follows. When repayment begins that accrued interest capitalizes — it is added to your principal — so you start repaying a larger balance than you originally borrowed. The calculator shows this as the principal at repayment start.
What is the difference between subsidized and unsubsidized loans?
On a subsidized loan the government pays the interest while you are enrolled and during grace, so repayment starts on exactly what you borrowed. On an unsubsidized loan that interest accrues to you and usually capitalizes. The calculator’s “cost of being unsubsidized” figure shows how much more that adds over the life of the loan.
What does capitalization mean?
Capitalization is when unpaid accrued interest is added to your loan principal — typically when repayment begins. After it happens, you pay interest on that larger balance, so interest compounds on interest. Paying the accruing interest while still in school avoids capitalization and lowers the total cost.
Should I pay interest while still in school?
If you can, yes. Paying the interest as it accrues stops it from capitalizing, so repayment begins on the amount you actually borrowed rather than a larger figure. Set the “accrued interest” option to “paid in school” to see the saving — it is usually more than the modest in-school payments cost.
Does this calculator model income-driven repayment?
No. It models a standard fixed-payment plan with the same monthly amount over the term. Income-driven repayment plans base payments on your income, change yearly, and may lead to forgiveness — their maths depends on rules this tool does not approximate. Use these figures as a standard-plan baseline.
How does an extra payment help?
Any amount above the minimum goes straight to principal, so the balance falls faster, less interest accrues on it, and the loan clears early. Enter an extra monthly amount and the calculator shows the interest saved and how much sooner you finish.