CalculateY
Quick Answer
A $35,000 student loan at 5.5% for 10 years has an estimated monthly payment of approximately $380. Estimated total interest over the standard repayment period is approximately $10,558.
Common Examples
| Input | Result |
|---|---|
| $30,000 at 5% for 10 years | Estimated $318/month, $8,184 total interest |
| $35,000 at 5.5% for 10 years | Estimated $380/month, $10,558 total interest |
| $50,000 at 6% for 10 years | Estimated $555/month, $16,613 total interest |
| $40,000 at 4.5% for 10 years, $100 extra/month | Estimated $414/month base, payoff in ~84 months with extra |
| $25,000 at 6.5% for 10 years | Estimated $284/month, $9,060 total interest |
How It Works
This calculator uses the standard amortization formula to estimate the fixed monthly payment on a student loan:
M = P x [r(1 + r)^n] / [(1 + r)^n - 1]
Where:
- M = estimated monthly payment
- P = loan balance (principal owed)
- r = monthly interest rate (annual rate divided by 12, expressed as a decimal)
- n = total number of monthly payments (repayment term in years multiplied by 12)
The estimated total paid over the life of the loan is M x n. The estimated total interest is the total paid minus the original balance.
Extra Payment Simulation
When an extra monthly payment amount is provided, the calculator simulates month-by-month repayment with the additional amount applied directly to the principal. Each month:
- Interest accrues on the remaining balance: Interest = Balance x r
- The standard payment plus the extra payment is applied
- The new balance equals the previous balance plus interest minus the total payment
The simulation compares the results with and without extra payments to show the estimated interest saved and months saved.
Most federal student loans use the Standard Repayment Plan with a 10-year term. Private loans may have different terms. This calculator works for any fixed-rate student loan regardless of term length.
Worked Example
For a $35,000 student loan at 5.5% annual interest over 10 years (120 months): Monthly rate r = 0.055 / 12 = 0.004583. Factor = (1.004583)^120 = 1.7282. M = 35,000 x [0.004583 x 1.7282] / [1.7282 - 1] = 35,000 x 0.007923 / 0.7282 ≈ $380.48 per month. Estimated total paid = $380.48 x 120 = $45,558. Estimated total interest = $45,558 - $35,000 = $10,558.
With an extra $100/month ($480.48 total), the loan pays off in approximately 86 months instead of 120, saving roughly 34 months and an estimated $2,999 in interest.