Reviewed by:Dr. Emily White, PhD
Financial aid expert and former university financial aid director. Author of “The Student Debt Dilemma,” specializing in repayment strategies.
See if you can save money by refinancing your student loans. Add one or more of your current loans, then enter a new refinance offer to compare your payments and total interest paid.
Student Loan Refinance Calculator
Your Current Loans
New Refinance Offer
Student Loan Refinance Formulas
This calculator first finds the monthly payment for each of your current loans. It then calculates a new single payment for your new loan, based on the *total combined balance* of your old loans.
Monthly Payment (M):
M = P x [ r(1+r)^n ] / [ (1+r)^n – 1 ]
Weighted Avg. Rate:
Sum(Balance * Rate) / Total Balance
Student loan refinancing is the process of taking out a **new private loan** to pay off one or more of your existing student loans (both federal and private). The new loan completely replaces your old ones, leaving you with a single loan and a single monthly payment.
People typically refinance their student loans to achieve one or more of these goals:
Lower Interest Rate: If your credit has improved since you first took out your loans, you may qualify for a lower interest rate, which could save you thousands of dollars over the life of the loan.
Lower Monthly Payment: By extending the loan term (e.g., from 10 years to 15 years), you can significantly reduce your monthly payment, freeing up cash flow. Note: This may cause you to pay more total interest over time.
Payment Simplification: If you’re juggling multiple loan payments to different servicers, refinancing combines them into one easy-to-manage payment.
Warning: If you refinance *federal* student loans, you will permanently lose access to federal benefits, such as income-driven repayment (IDR) plans, forbearance/deferment options, and any potential for public service loan forgiveness (PSLF) or other government forgiveness programs. Always consider this trade-off carefully.
How to Calculate Refinancing Savings (Example)
A graduate has two student loans:
Loan 1: $20,000 balance, 6.8% rate, 10 years left.
Loan 2: $15,000 balance, 5.5% rate, 10 years left.
They are offered a new private loan to consolidate both (total balance $35,000) with a 4.5% rate and a new 10-year term.
Calculate Current Total Payment:
Loan 1 Payment = $230.16/mo.
Loan 2 Payment = $162.77/mo.
Total Current Payment = $392.93/mo.
Calculate New Payment:
P = $35,000, r = (0.045 / 12), n = 120.
New Payment (M) = $360.05/mo.
What is the difference between refinancing and consolidation?
Refinancing involves getting a *new private loan* to pay off old loans, usually to get a lower interest rate. Consolidation is a specific *federal* program (Direct Consolidation Loan) that combines multiple federal loans into one new federal loan. Consolidation does *not* lower your interest rate (it gives you a weighted average), but it does simplify payments and can make you eligible for certain repayment plans.
When should I refinance my student loans?
The best time to refinance is when you have a stable income, a good credit score (typically 680+), and you can secure a new interest rate that is significantly lower than your current average rate. It’s generally not recommended if you are relying on federal loan protections or pursuing loan forgiveness.
Can I refinance only some of my student loans?
Yes. Many people choose to only refinance their private student loans (which have no federal benefits) or their federal loans with the highest interest rates (like Grad PLUS loans), while keeping their other federal loans separate to retain their protections.
document.addEventListener(‘DOMContentLoaded’, function() {
// — Get Elements —
const loanListContainer = document.getElementById(‘student-refi-current-loans-list’);
const addLoanBtn = document.getElementById(‘student-refi-add-loan-btn’);
const newRateInput = document.getElementById(‘student-refi-new-rate’);
const newTermInput = document.getElementById(‘student-refi-new-term’);
const calculateBtn = document.getElementById(‘student-refi-calculate-btn’);
const resetBtn = document.getElementById(‘student-refi-reset-btn’);
const resultsDiv = document.getElementById(‘student-refi-calculation-steps’);
let loanIdCounter = 1;
// — Attach Event Listeners —
addLoanBtn.addEventListener(‘click’, addLoanRow);
calculateBtn.addEventListener(‘click’, calculateRefinance);
resetBtn.addEventListener(‘click’, resetCalculator);
loanListContainer.addEventListener(‘click’, function(e) {
if (e.target.classList.contains(‘student-refi-delete-loan-btn’)) {
e.target.closest(‘.student-refi-loan-row’).remove();
checkLoanRows();
}
});
// — Helper Functions —
/**
* Calculates the monthly payment (M).
*/
function calculateMonthlyPayment(P, r, n) {
if (P <= 0 || n <= 0) return 0;
if (r <= 0) return P / n; // 0% interest
return P * (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) – 1);
}
/**
* Adds a new dynamic loan row to the list.
*/
function addLoanRow() {
loanIdCounter++;
const row = document.createElement('div');
row.className = 'student-refi-loan-row';
row.dataset.id = loanIdCounter;
row.innerHTML = `
`;
loanListContainer.appendChild(row);
checkLoanRows();
}
/**
* Hides the delete button if only one row is left.
*/
function checkLoanRows() {
const rows = loanListContainer.querySelectorAll(‘.student-refi-loan-row’);
rows.forEach((row, index) => {
const deleteBtn = row.querySelector(‘.student-refi-delete-loan-btn’);
deleteBtn.style.visibility = (rows.length > 1) ? ‘visible’ : ‘hidden’;
});
}
/**
* Main calculation function.
*/
function calculateRefinance() {
let currentTotalBalance = 0;
let currentTotalMonthlyPayment = 0;
let currentTotalInterest = 0;
let currentWeightedRateNumerator = 0;
let valid = true;
// — 1. Get and parse all current loans —
const loanRows = loanListContainer.querySelectorAll(‘.student-refi-loan-row’);
loanRows.forEach(row => {
const balance = parseFloat(row.querySelector(‘.student-refi-balance’).value);
const rate = parseFloat(row.querySelector(‘.student-refi-rate’).value);
const term = parseFloat(row.querySelector(‘.student-refi-term’).value);
if (isNaN(balance) || balance <= 0 || isNaN(rate) || rate < 0 || isNaN(term) || term 0, Rate >= 0, Term > 0).’);
return;
}
const currentWeightedAvgRate = (currentWeightedRateNumerator / currentTotalBalance) * 100;
// — 2. Get and parse new loan offer —
const newRate = parseFloat(newRateInput.value);
const newTerm = parseFloat(newTermInput.value);
if (isNaN(newRate) || newRate < 0) {
showError('Please enter a valid New Interest Rate.');
return;
}
if (isNaN(newTerm) || newTerm <= 0) {
showError('Please enter a valid New Loan Term in years.');
return;
}
// — 3. Calculate new loan metrics —
const newP = currentTotalBalance;
const newN = newTerm * 12;
const newR = (newRate / 100) / 12;
const newMonthlyPayment = calculateMonthlyPayment(newP, newR, newN);
const newTotalPaid = newMonthlyPayment * newN;
const newTotalInterest = newTotalPaid – newP;
// — 4. Calculate Savings —
const monthlySavings = currentTotalMonthlyPayment – newMonthlyPayment;
const totalInterestSaved = currentTotalInterest – newTotalInterest;
// — 5. Display Results —
showResults(
currentTotalBalance, currentWeightedAvgRate, currentTotalMonthlyPayment, currentTotalInterest,
newMonthlyPayment, newTotalInterest,
monthlySavings, totalInterestSaved
);
}
/**
* Displays the results in the results div.
*/
function showResults(
totalBalance, avgRate, currentMonthly, currentInterest,
newMonthly, newInterest,
monthlySavings, totalInterestSaved
) {
resultsDiv.style.display = 'block';
resultsDiv.classList.remove('student-refi-error');
resultsDiv.innerHTML = `
Your Current Loans
Total Monthly Payment${formatCurrency(currentMonthly)}
Total Balance:${formatCurrency(totalBalance)}
Weighted Avg. Rate:${avgRate.toFixed(2)}%
Total Interest (to payoff):${formatCurrency(currentInterest)}
New Refinance Loan
New Monthly Payment${formatCurrency(newMonthly)}
Total Balance:${formatCurrency(totalBalance)}
New Rate:${newRateInput.value}%
Total Interest (to payoff):${formatCurrency(newInterest)}
By refinancing, your new monthly payment will be ${formatCurrency(newMonthly)}.
This is a ${formatCurrency(Math.abs(monthlySavings))} ${monthlySavings > 0 ? ‘decrease’ : ‘increase’} in your monthly payment.
${totalInterestSaved <= 0 ? '
Warning: Based on these terms, refinancing will cost you more money in total interest, even if your monthly payment is lower.
‘ : ”}
`;
// Scroll to results on mobile
if (window.innerWidth < 768) {
resultsDiv.scrollIntoView({ behavior: 'smooth' });
}
}
function showError(message) {
resultsDiv.style.display = 'block';
resultsDiv.innerHTML = `
${message}
`;
}
function resetCalculator() {
loanListContainer.innerHTML = ”;
loanIdCounter = 0;
addLoanRow(); // Add the first row back
newRateInput.value = ”;
newTermInput.value = ”;
resultsDiv.style.display = ‘none’;
resultsDiv.innerHTML = ”;
// Clear the first row inputs
loanListContainer.querySelector(‘.student-refi-balance’).value = ”;
loanListContainer.querySelector(‘.student-refi-rate’).value = ”;
loanListContainer.querySelector(‘.student-refi-term’).value = ”;
}
// Initialize
checkLoanRows(); // Call on load to hide the first delete button
function formatCurrency(number) {
number = parseFloat(number);
return ‘$’ + number.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, ‘$&,’);
}
});
