What Will Your Student Loan Really Cost After School?
See how interest accrues while you're in school, what your balance will be at graduation, and plan your repayment strategy with a detailed amortization breakdown.
What This Calculator Does
A student loan repayment calculator models the two phases of student debt: the in-school deferment period (where interest accrues but payments aren't required) plus the 6-month post-graduation grace period, followed by the standard repayment phase. It shows the true cost of your loan including capitalized interest.
How It Works
During the in-school and grace period, unpaid interest is added to your principal balance (capitalization). The calculator computes this growing balance month by month, then amortizes the final balance over your chosen repayment term to show your actual monthly payment and total cost.
Why It Matters
Most students don't realize their loan balance grows while they're in school. A $35,000 loan at 6.8% with 2 years remaining in school will become over $38,000 by the time payments start — and you'll pay interest on that higher balance for the entire repayment period. Understanding this helps you make smarter decisions about in-school payments.
Loan Details
Most borrowers pay $0 while in school. Even small payments reduce capitalized interest.
Phase 1: In-School + Grace Period
Original Balance
$35,000
Deferment Period
30 mo
24 school + 6 grace
Capitalized Interest
$6,466
Balance at Repayment
$41,466
$6,466 in interest will be added to your principal because no payments are made during deferment. This means you'll pay interest on interest during repayment.
Phase 2: Repayment
Monthly Payment
$477.19
Total Interest (Repayment)
$15,797
Total Interest (All)
$22,263
Total Cost of Loan
$57,263
💡 Smart Strategy: Pay Interest While in School
If you paid just the monthly interest of $198.33 while in school, you'd prevent interest from capitalizing and save significantly:
In-School Payment
$198.33/mo
Lower Repayment
$402.78/mo
Save $74.41/mo
Total Lifetime Savings
$2,979
Disclosure: For fixed rate loans only. Variable rates may be more or less based on interest rate movements. This calculator assumes interest capitalizes at the end of the deferment period (in-school + 6-month grace period). Actual terms may vary by lender. Results are estimates for educational purposes only.
How Student Loan Repayment Is Calculated
During the in-school and grace period, unpaid interest is added to your principal balance (capitalization). The calculator computes this growing balance month by month, then amortizes the final balance over your chosen repayment term to show your actual monthly payment and total cost.
Phase 1 (in-school + 6-month grace): each month, interest=balance*monthlyRate added to balance, minus any inSchoolPayment (capped so it can't exceed interest+balance); repeated for (yearsRemaining*12+monthsRemaining) school months plus a fixed 6-month grace period. balanceAtRepayment = resulting balance after capitalization. Phase 2: monthlyPayment = standard amortization of balanceAtRepayment at interestRate over repaymentTerm (years*12), simulated month by month for totals/schedule. totalInterest = totalInSchoolInterest + totalRepaymentInterest; totalCost = loanAmount + totalInterest - (inSchoolPayment*totalDefermentMonths). Also computes an interest-only-in-school comparison scenario with no capitalization. Where: loanAmount, interestRate (annual %), yearsRemaining/monthsRemaining (time before graduation), inSchoolPayment (optional monthly payment while in school), repaymentTerm (yrs). Assumptions: fixed 6-month grace period (GRACE_PERIOD_MONTHS=6); interest capitalizes monthly during school+grace (added to balance); monthly compounding; single fixed rate across both phases; no caps/subsidies for federal loan types modeled.
Key Takeaways
- •Even small in-school payments on interest can save thousands over the life of the loan
- •The 6-month grace period after graduation still accrues interest on most loan types
- •Subsidized federal loans don't accrue interest while in school — unsubsidized and private loans do
- •Consider paying at least the monthly interest while in school to prevent capitalization
- •Choose the shortest repayment term you can afford to minimize total interest paid
- •Set up autopay immediately after graduation for a potential 0.25% rate discount
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