PMI Insurance Rates Calculator
.pmi-calculator-container {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
background: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.pmi-calculator-header {
text-align: center;
margin-bottom: 25px;
border-bottom: 2px solid #2c3e50;
padding-bottom: 15px;
}
.pmi-calculator-header h2 {
color: #2c3e50;
margin: 0;
font-size: 24px;
}
.pmi-form-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
.pmi-input-group {
margin-bottom: 15px;
}
.pmi-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #444;
font-size: 14px;
}
.pmi-input-group input, .pmi-input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s;
}
.pmi-input-group input:focus, .pmi-input-group select:focus {
border-color: #3498db;
outline: none;
}
.pmi-btn {
grid-column: 1 / -1;
background-color: #2980b9;
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background-color 0.3s;
}
.pmi-btn:hover {
background-color: #1f6391;
}
.pmi-results {
margin-top: 30px;
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 6px;
padding: 20px;
display: none;
}
.pmi-result-item {
display: flex;
justify-content: space-between;
align-items: center;
padding: 10px 0;
border-bottom: 1px solid #ddd;
}
.pmi-result-item:last-child {
border-bottom: none;
}
.pmi-result-label {
font-weight: 500;
color: #555;
}
.pmi-result-value {
font-weight: 700;
color: #2c3e50;
font-size: 18px;
}
.pmi-result-value.highlight {
color: #c0392b;
font-size: 20px;
}
.pmi-alert {
padding: 10px;
background-color: #fff3cd;
color: #856404;
border: 1px solid #ffeeba;
border-radius: 4px;
margin-top: 15px;
font-size: 14px;
display: none;
}
.pmi-content {
margin-top: 40px;
line-height: 1.6;
color: #333;
}
.pmi-content h3 {
color: #2c3e50;
margin-top: 25px;
}
.pmi-content ul {
padding-left: 20px;
}
@media (max-width: 600px) {
.pmi-form-grid {
grid-template-columns: 1fr;
}
}
Calculated LTV Ratio:
0%
Estimated Annual PMI Rate:
0%
Monthly PMI Premium:
$0.00
Annual PMI Cost:
$0.00
Est. Duration of PMI (Months):
0
Total PMI Cost (Lifetime):
$0.00
Understanding Your PMI Calculation
Private Mortgage Insurance (PMI) is a risk management policy required by lenders for conventional loans where the borrower has less than 20% equity in the property. Unlike homeowner's insurance, this policy protects the lender, not the property owner.
Key Factors Affecting PMI Rates
Your calculated PMI premium is primarily determined by two variables:
- LTV (Loan-to-Value) Ratio: This is calculated by dividing your Mortgage Balance by the Property Value. PMI is generally required if this ratio is above 80%. As the LTV increases (closer to 100%), the insurance risk rises, leading to higher premiums.
- Credit Score: This is the most significant multiplier. Borrowers with scores above 760 may pay rates as low as 0.30% annually, while scores below 640 can see rates exceeding 2.0% of the loan balance.
When Does PMI End?
Under the Homeowners Protection Act, PMI must automatically terminate when your principal balance is scheduled to reach 78% of the original property value. You can also request cancellation once your balance drops to 80% of the original value (assuming a good payment history). The calculation above estimates the total cost based on the scheduled amortization to hit that 78% threshold.
function calculatePMI() {
// 1. Get Input Values
var propValue = parseFloat(document.getElementById('propertyValue').value);
var loanAmt = parseFloat(document.getElementById('loanPrincipal').value);
var baseRate = parseFloat(document.getElementById('creditScoreTier').value);
var years = parseInt(document.getElementById('loanDuration').value);
// DOM Elements for Output
var resultDiv = document.getElementById('pmiResults');
var alertDiv = document.getElementById('pmiAlert');
var outLTV = document.getElementById('displayLTV');
var outRate = document.getElementById('displayRate');
var outMonthly = document.getElementById('displayMonthly');
var outYearly = document.getElementById('displayYearly');
var outMonths = document.getElementById('displayMonths');
var outTotal = document.getElementById('displayTotal');
// Reset Display
alertDiv.style.display = 'none';
resultDiv.style.display = 'none';
// 2. Validation
if (isNaN(propValue) || isNaN(loanAmt) || propValue <= 0 || loanAmt propValue) {
alertDiv.innerHTML = "Mortgage Balance cannot exceed Property Value for this standard calculation.";
alertDiv.style.display = 'block';
return;
}
// 3. Calculate LTV
var ltv = (loanAmt / propValue) * 100;
outLTV.innerText = ltv.toFixed(2) + "%";
// 4. PMI Logic Check
if (ltv <= 80) {
resultDiv.style.display = 'block';
outRate.innerText = "0% (Not Required)";
outMonthly.innerText = "$0.00";
outYearly.innerText = "$0.00";
outMonths.innerText = "0";
outTotal.innerText = "$0.00";
alertDiv.innerHTML = "
Good News: Since your LTV is 80% or lower, PMI is typically not required.";
alertDiv.style.display = 'block';
return;
}
// 5. Adjust Rate based on LTV density
// Base rate comes from credit score input. We adjust it if LTV is very high (95%+) or lower (85%).
var adjustedRate = baseRate;
if (ltv > 95) {
adjustedRate = baseRate * 1.35; // High risk premium
} else if (ltv > 90) {
adjustedRate = baseRate * 1.15; // Moderate risk premium
} else if (ltv > 85) {
adjustedRate = baseRate; // Standard (Input baseline assumes ~90% context)
} else {
adjustedRate = baseRate * 0.75; // Lower risk discount (80.01% – 85%)
}
// 6. Calculate Costs
// PMI is calculated on the annual loan balance percentage
var annualCost = loanAmt * (adjustedRate / 100);
var monthlyCost = annualCost / 12;
// 7. Calculate Duration (Months until LTV hits 78%)
// We assume a standard market interest rate for amortization to find the paydown speed
var assumedInterestRate = 6.5; // Fixed assumption for amortization only
var monthlyInterest = (assumedInterestRate / 100) / 12;
var totalPayments = years * 12;
// Calculate standard mortgage payment (P&I) to determine principal paydown speed
var x = Math.pow(1 + monthlyInterest, totalPayments);
var monthlyPI = (loanAmt * x * monthlyInterest) / (x – 1);
var currentBalance = loanAmt;
var targetBalance = propValue * 0.78;
var monthsWithPMI = 0;
// Loop to simulate amortization
while (currentBalance > targetBalance && monthsWithPMI < totalPayments) {
var interestPart = currentBalance * monthlyInterest;
var principalPart = monthlyPI – interestPart;
currentBalance -= principalPart;
monthsWithPMI++;
}
var totalPMICost = monthlyCost * monthsWithPMI;
// 8. Output Results
outRate.innerText = adjustedRate.toFixed(2) + "%";
outMonthly.innerText = "$" + monthlyCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
outYearly.innerText = "$" + annualCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
outMonths.innerText = monthsWithPMI;
outTotal.innerText = "$" + totalPMICost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
resultDiv.style.display = 'block';
}