The total number of paying customers on the 1st day of the month.
The total number of paying customers on the last day of the month.
New customers who signed up during this specific month.
Customer Retention Rate
0.00%
Customer Churn Rate0.00%
Customers Retained0
Customers Lost (Churned)0
Understanding Monthly Retention Rate
Customer Retention Rate (CRR) is a critical metric for subscription-based businesses, SaaS companies, and service providers. It measures the percentage of customers a company retains over a specific period, in this case, a month. A high retention rate indicates a loyal customer base, a strong product-market fit, and efficient customer success efforts.
Unlike acquisition metrics, which focus on growth, retention focuses on the health and longevity of your existing relationships. It is generally far more cost-effective to retain an existing customer than to acquire a new one.
The Retention Rate Formula
To calculate your monthly retention rate, you need three specific data points. The formula isolates the customers who stayed by removing the "noise" of new customers acquired during the month.
Retention Rate = [ ( E – N ) / S ] × 100
Where:
E = Number of customers at the End of the month.
N = Number of New customers acquired during the month.
S = Number of customers at the Start of the month.
How the Calculation Works
Let's look at a practical example to clarify the math:
You start the month with 200 customers (S).
During the month, you lose 10 customers but gain 30 new customers (N).
You end the month with 220 customers (E).
Using the calculator above:
First, we calculate how many of the original customers remained: 220 (End) – 30 (New) = 190.
Next, we divide that by the starting count: 190 / 200 = 0.95.
Finally, multiply by 100 to get the percentage: 95% Retention Rate.
Consequently, your Churn Rate would be 5% (100% – 95%).
What is a Good Retention Rate?
Benchmarks vary significantly by industry:
Consumer SaaS: Good retention is often considered above 92-94% monthly.
Enterprise SaaS: Often aims for 98-99% monthly retention.
E-commerce: Retention is usually lower, typically around 30-40% depending on purchase frequency.
Why Does This Matter for SEO and Growth?
From a growth perspective, retention is the lever that compounds growth. If your "bucket is leaking" (high churn), pouring more water in (traffic/acquisition) becomes inefficient. High retention increases Customer Lifetime Value (LTV), allowing you to spend more on acquiring new customers via paid ads or organic SEO strategies.
function calculateRetention() {
// Get input values using var
var startInput = document.getElementById('custStart');
var endInput = document.getElementById('custEnd');
var newInput = document.getElementById('custNew');
var errorDiv = document.getElementById('error-message');
var resultsDiv = document.getElementById('retention-results');
// Parse values
var S = parseFloat(startInput.value);
var E = parseFloat(endInput.value);
var N = parseFloat(newInput.value);
// Reset display
errorDiv.style.display = 'none';
resultsDiv.style.display = 'none';
// Validation Logic
if (isNaN(S) || isNaN(E) || isNaN(N)) {
errorDiv.innerHTML = "Please enter valid numbers in all fields.";
errorDiv.style.display = 'block';
return;
}
if (S <= 0) {
errorDiv.innerHTML = "Customers at Start of Month must be greater than 0.";
errorDiv.style.display = 'block';
return;
}
if (N < 0 || E < 0) {
errorDiv.innerHTML = "Customer counts cannot be negative.";
errorDiv.style.display = 'block';
return;
}
// Logic check: Customers Retained cannot be negative.
// E – N represents the customers from the start who are still there.
// If (E – N) Total Ending Customers, which is mathematically impossible
// unless there was an error in counting (e.g. data mismatch).
var retainedCount = E – N;
if (retainedCount S, user might have counted reactivations as retained, or data error.
if (retainedCount > S) {
errorDiv.innerHTML = "Invalid Data: Calculated retained customers (" + retainedCount + ") exceeds starting customers (" + S + "). Ensure 'New Customers' includes all additions/reactivations.";
errorDiv.style.display = 'block';
return;
}
// Calculation
var retentionRate = (retainedCount / S) * 100;
var churnRate = 100 – retentionRate;
var lostCount = S – retainedCount;
// Display Results
document.getElementById('rr-percentage').innerHTML = retentionRate.toFixed(2) + '%';
document.getElementById('churn-percentage').innerHTML = churnRate.toFixed(2) + '%';
document.getElementById('retained-count').innerHTML = retainedCount;
document.getElementById('lost-count').innerHTML = lostCount;
// Dynamic coloring for the big stat
var statColor = retentionRate >= 90 ? '#28a745' : (retentionRate >= 80 ? '#fd7e14' : '#dc3545');
document.getElementById('rr-percentage').style.color = statColor;
resultsDiv.style.display = 'block';
}