Student Loan Calculator
Calculate monthly student loan repayments, total interest charges, and loan amortization schedules with optional extra monthly principal payments.
Calculation Results
Student Loan Monthly Payment Formula
Monthly Payment = [Principal × (r × (1 + r)^n)] / [(1 + r)^n − 1], where r = APR / 12 and n = Term in Months- Standard 10-year repayment schedule amortizes balance across 120 equal monthly installments.
- Handles zero-interest promotional/subsidized periods accurately.
- Demonstrates the compounding power of extra monthly payments directly reducing loan principal.
- Calculates exact interest saved and repayment timeline shortening.
Step-by-Step Worked Example
Calculation Steps:
- Standard Monthly Payment: $35,000 × [0.005 × (1.005)^120] / [(1.005)^120 − 1] = $388.57.
- Standard 10-Year Repayment: $388.57 × 120 = $46,629 ($11,629 total interest).
- With $75 Extra ($463.57/mo): Loan pays off in 94 months (7.8 years instead of 10).
- Interest Paid with Extra: $8,790. Total Interest Saved: $2,839.
How to Use This Calculator
- 1Enter your total outstanding student loan balance.
- 2Input the annual interest rate (APR) across your loans.
- 3Select your repayment term length (standard is 10 years).
- 4Test different extra monthly payments to see your interest savings.
Assumptions & Limitations
- Assumes a fixed interest rate throughout the entire repayment term.
- Extra payments are applied directly to principal reduction without prepayment penalties.
Frequently Asked Questions
Are there prepayment penalties on student loans in the U.S.?
No, federal law prohibits any prepayment penalties on both federal and private student loans. You can pay extra at any time to save interest.
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