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Student Loan Calculator
Calculate your monthly student loan payment, total interest over the loan life, and payoff date. Compare different loan amounts, interest rates, and repayment terms to understand the true cost of your education financing.
Student loan debt in the US totals over $1.7 trillion across more than 43 million borrowers. Understanding your monthly payments and total interest before borrowing helps you make informed decisions about how much to borrow, choose between federal and private loans, and select the right repayment plan.
Formula
Monthly Payment = P × [r(1+r)^n] / [(1+r)^n - 1] | Total Interest = Monthly Payment × n - Principal | r = Annual Rate / 12
Federal vs Private Student Loans
Always exhaust federal student loans before considering private loans. Federal loans offer income-driven repayment plans, loan forgiveness programs, deferment, and forbearance — protections that private loans do not provide. Private loans may have lower interest rates for excellent credit borrowers but lack these critical consumer protections.
Loan Type
Interest Rate
Key Feature
Borrowing Limit
Federal Direct Subsidized
5.5% (2024-25)
No interest while enrolled
$23,000 lifetime max
Federal Direct Unsubsidized
5.5% (undergrad)
Interest accrues in school
$31,000 independent limit
Federal PLUS Loans
8.05% (2024-25)
Parents or grad students
No set limit
Private Loans
4-15% variable
Credit-based rates
Varies by lender
Federal Perkins
5% fixed (discontinued)
Need-based, low rate
Limited availability
Income-Driven Repayment Plans
Federal loans offer Income-Driven Repayment (IDR) plans that cap payments at 5-20% of discretionary income: SAVE Plan (new, 5% of discretionary for undergraduate loans), PAYE (10%), IBR (10-15%), and ICR (20%). After 10-25 years of payments, remaining balance is forgiven. Public Service Loan Forgiveness (PSLF) forgives federal loans after 10 years working for government or nonprofit employers.
True Cost of Student Loans
Interest dramatically increases the total cost. $30,000 at 5.5% over 10 years: monthly payment $325, total interest paid $9,003. Same loan over 20 years: monthly payment $206, total interest $19,428 — more than doubling the interest cost. Pay more than the minimum whenever possible to reduce total interest paid.
Frequently Asked Questions
At 5.5% over 10 years: $541/month, total interest $14,915. At 5.5% over 20 years: $344/month, total interest $32,500. At 6.5% over 10 years: $567/month, total interest $17,981. Use income-driven repayment if monthly payments exceed 10% of your gross monthly income.
If loan rate is below 5%: consider investing — stock market historically returns 7-10%/year. If loan rate is above 6-7%: pay off loans first (guaranteed return = your interest rate). At 5-6%: split between investing and extra loan payments. Always contribute enough to get full employer 401k match before extra loan payments.
Federal student loans have a 6-month grace period after graduation, leaving school, or dropping below half-time enrollment before payments begin. PLUS loans enter repayment 60 days after full disbursement. Interest on unsubsidized loans continues accruing during the grace period — consider making interest-only payments during this period.
Public Service Loan Forgiveness (PSLF): 10 years of payments while working full-time for government or nonprofits — remaining balance forgiven tax-free. Teacher Loan Forgiveness: up to $17,500 after 5 years of teaching in low-income schools. Income-Driven Repayment forgiveness: 20-25 years of payments, but forgiven amount is taxable income.
Most private lenders require 650+ credit score. Best rates typically require 720+. Students usually need a creditworthy cosigner (parent with 680+ credit score). Adding a cosigner often reduces the interest rate by 1-3 percentage points, saving thousands over the loan life.
Daily interest = Principal × Annual Rate / 365. Monthly interest = Daily interest × 30. Example: $25,000 at 6% annual rate: Daily = $25,000 × 0.06/365 = $4.11/day. Monthly = $4.11 × 30 = $123.30/month. If your monthly payment is less than $123.30, your loan balance grows — negative amortization.