Insurance Premium Pro Rata Calculator

Insurance Premium Pro Rata Calculator

Calculate refunds and earned premiums for mid-term policy cancellations.

Calculation Results

Unearned Premium (Refund) $0.00

Earned Premium (Cost) $0.00

Days Elapsed: 0

Days Remaining: 0

Total Policy Term: 0 days

Refund Percentage: 0%

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What is a Pro Rata Insurance Premium?

In the insurance industry, "Pro Rata" refers to the method of calculating a refund or an additional premium based on the actual number of days a policy was in force. Unlike "Short Rate" cancellations, which often include a penalty fee for ending a policy early, a Pro Rata calculation is strictly mathematical and proportional.

The Pro Rata Formula

The math behind a pro rata calculation is straightforward:

1. Daily Rate = Total Premium / Total Number of Days in Policy Period.
2. Earned Premium = Daily Rate × Number of Days Policy was Active.
3. Unearned (Refund) Premium = Total Premium – Earned Premium.

Example Calculation

Imagine you purchased a one-year (365 days) car insurance policy for $1,200 starting January 1st. If you decide to cancel the policy on June 30th (after 181 days of coverage):

• Daily Cost: $1,200 / 365 = $3.2876 per day.
• Earned Premium (Insurers portion): 181 days × $3.2876 = $595.06.
• Unearned Premium (Your refund): $1,200 – $595.06 = $604.94.

When is Pro Rata Used?

Pro rata calculations are most commonly used when:

• The insurance company cancels the policy for reasons other than non-payment.
• You make a change mid-term (like adding a new driver) and need to pay the difference for the remaining days.
• Standard policy language dictates pro rata refunds for voluntary cancellations (common in commercial and professional liability lines).

Note: This calculator assumes a standard proportional distribution. Always check your specific policy wording, as some insurers may apply minimum earned premiums or service fees during cancellation.

function calculateProRata() { var premium = parseFloat(document.getElementById('totalPremium').value); var start = new Date(document.getElementById('startDate').value); var end = new Date(document.getElementById('endDate').value); var cancel = new Date(document.getElementById('cancelDate').value); var errorDiv = document.getElementById('errorArea'); var resultsDiv = document.getElementById('resultsArea'); // Reset display errorDiv.style.display = 'none'; resultsDiv.style.display = 'none'; // Validation if (isNaN(premium) || premium <= 0) { showError("Please enter a valid premium amount."); return; } if (isNaN(start.getTime()) || isNaN(end.getTime()) || isNaN(cancel.getTime())) { showError("Please select all three dates (Start, End, and Cancellation)."); return; } if (end <= start) { showError("Expiration date must be after the start date."); return; } if (cancel end) { showError("Cancellation date must fall between the start and expiration dates."); return; } // Calculation logic var msPerDay = 24 * 60 * 60 * 1000; // Calculate Total Days var totalTermDays = Math.round((end – start) / msPerDay); // Calculate Days Used (Elapsed) var daysUsed = Math.round((cancel – start) / msPerDay); // Calculate Days Left var daysLeft = totalTermDays – daysUsed; // Financial Math var dailyRate = premium / totalTermDays; var earned = dailyRate * daysUsed; var unearned = premium – earned; var refundPercentage = (unearned / premium) * 100; // Display results document.getElementById('unearnedDisplay').innerText = '$' + unearned.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('earnedDisplay').innerText = '$' + earned.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2}); document.getElementById('daysUsed').innerText = daysUsed; document.getElementById('daysLeft').innerText = daysLeft; document.getElementById('totalDays').innerText = totalTermDays; document.getElementById('refundPercent').innerText = refundPercentage.toFixed(2); resultsDiv.style.display = 'block'; } function showError(msg) { var errorDiv = document.getElementById('errorArea'); errorDiv.innerText = msg; errorDiv.style.display = 'block'; }