Student Loan Calculator
What's your monthly payment and total cost? How much can you save by paying extra? Is refinancing worth it? Three tabs โ one calculator.
Try a scenario
How to Use This Calculator
Tab "Repayment Schedule"
Enter your loan balance, annual interest rate, and repayment term. The result shows your monthly payment, total interest paid, and total cost. Click "Show year-by-year summary" for a full amortisation table and a visual chart of your remaining balance over time.
Tab "Pay Off Faster"
Enter the same loan details, then add an extra monthly payment. The calculator shows how many years and months you shave off, how much interest you save, and your new estimated payoff date. Even small extra payments can make a significant difference.
Tab "Refinance"
Enter your remaining balance, current rate, new rate, and remaining term. Optionally add a refinancing fee. The result shows monthly savings, total savings over the full term, and the break-even point โ how many months until the fee pays for itself.
The Formulas
PMT = P × r_m × (1 + r_m)^n / ((1 + r_m)^n − 1)
where P = loan balance, r_m = annual rate / 12, n = total months
Total interest paid:
Total interest = (PMT × n) − P
Total cost of loan:
Total cost = PMT × n
With extra payment:
Apply extra payment entirely to principal each month.
Repeat until balance = 0. Count months saved.
Refinance monthly savings:
Savings/month = current PMT − new PMT
Break-even (months):
Break-even = refinancing fee / monthly savings
All calculations use standard fixed-rate amortisation mathematics. No country-specific repayment rules, income thresholds, or government programmes are applied. Results are pre-tax estimates.
Worked Examples
Example 1 โ Standard repayment: $35,000 at 5.5% for 10 years
A graduate borrower has $35,000 in student loans at a fixed 5.5% annual rate and chooses a standard 10-year repayment plan.
The loan costs $10,558 in interest on top of the original $35,000. That is 30.2% of the loan balance as the true borrowing cost. Stretching to 20 years would lower the monthly payment but raise total interest to about $26,000.
Example 2 โ Pay off faster: same loan plus $100/month extra
The same borrower adds $100 to their monthly payment (total $480/month instead of $380).
By paying just $100 extra per month, the loan is paid off nearly 3 years early and saves $2,847 in interest โ a return of roughly $28 in savings for every extra $1 per month over the loan term.
Example 3 โ Refinance: $28,000 from 6.8% to 4.5%, 7 years remaining
A borrower has $28,000 left at 6.8% with 7 years remaining. A lender offers 4.5% for the same term at no fee.
Refinancing saves about $28 per month and $2,340 over the full remaining term. With no fee, the break-even is immediate โ every payment from month 1 is cheaper. If there is a $500 refinancing fee, the break-even is reached in about 18 months, after which all savings are pure benefit.
Understanding Student Loan Repayment
How Amortisation Works
Most student loans use amortisation: fixed monthly payments where early payments are mostly interest and later payments are mostly principal. In the first month of a $35,000 loan at 5.5%, about $160 goes to interest and $220 to principal. By year 8, the split reverses. This is why making extra payments early in the loan life saves the most interest โ you are reducing the principal that all future interest is calculated on.
The True Cost of a Longer Term
Extending the repayment term lowers the monthly payment but increases total interest paid substantially:
| Term | Monthly payment | Total interest | Total cost |
|---|---|---|---|
| 5 years | $671 | $5,249 | $40,249 |
| 10 years | $380 | $10,558 | $45,558 |
| 15 years | $287 | $16,600 | $51,600 |
| 20 years | $240 | $22,693 | $57,693 |
All figures for $35,000 at 5.5%. Going from 10 to 20 years saves $140/month but costs an extra $12,135 in interest over the life of the loan.
Extra Payments: Why They Work So Well
Every dollar of extra payment reduces your principal, which lowers the interest charged next month, which means more of your regular payment also goes to principal โ a compounding effect in reverse. The earlier you make extra payments, the greater the benefit. A single large extra payment in year 1 saves more than the same payment in year 9.
When Refinancing Makes Sense
Refinancing can reduce your interest rate if your credit score has improved or market rates have fallen since you originally borrowed. Key questions to ask: (1) Is the new rate materially lower? (2) Do the total savings exceed any refinancing fee? (3) Are you keeping the same term (not extending it)? (4) Will you lose any benefits tied to the original loan? This calculator handles the maths for points 1 to 3; consult your lender for point 4.
This Is a Universal Calculator
This tool uses pure loan mathematics and works for any fixed-rate loan in any currency. It does not model income-based repayment plans, government-specific thresholds, loan forgiveness programmes, variable rates, or country-specific indexation rules. For those, see the country-specific calculators below.
Frequently Asked Questions
Country-Specific Student Loan Calculators
For country-specific student loan rules, income thresholds, and government programmes: