Month over Month (MoM) Growth Rate Calculator
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What is Month over Month (MoM) Growth?
Month over Month (MoM) growth is a key performance indicator (KPI) used by businesses, investors, and analysts to measure the short-term momentum of a company or specific metric. It calculates the percentage change in a metric—such as revenue, active users, or website traffic—from one month compared to the immediately preceding month.
While Year over Year (YoY) growth accounts for seasonality, MoM growth is essential for identifying immediate trends, the impact of recent marketing campaigns, or sudden operational shifts. It is particularly vital for startups and fast-growing companies where monthly volatility is high and rapid adaptation is necessary.
The MoM Growth Formula
Calculating the monthly growth rate involves finding the difference between the current month's value and the prior month's value, dividing that by the prior month's value, and then multiplying by 100 to get a percentage.
Formula:
MoM Growth Rate = ((Current Month Value – Prior Month Value) / Prior Month Value) × 100
How to Use This Calculator
Using our calculator is straightforward. Here is a step-by-step guide:
- Step 1: Identify the metric you want to track (e.g., Monthly Recurring Revenue, Website Sessions, or Sales Count).
- Step 2: Enter the value of that metric for the Prior Month. For example, if you had 5,000 visitors in January, enter 5000.
- Step 3: Enter the value of the metric for the Current Month. For example, if you had 6,000 visitors in February, enter 6000.
- Step 4: Click "Calculate Growth" to see the percentage increase or decrease.
Realistic Calculation Example
Let's look at a practical scenario for an e-commerce store tracking sales revenue.
- Scenario: An online store generated $15,000 in October (Prior Month). In November, due to Black Friday sales, revenue jumped to $21,500 (Current Month).
- Calculation: ($21,500 – $15,000) = $6,500 difference.
- Division: $6,500 / $15,000 = 0.4333…
- Percentage: 0.4333 × 100 = 43.33%
In this example, the store experienced a 43.33% MoM growth rate in revenue.
Why Does MoM Growth Matter?
Tracking monthly growth helps you answer critical business questions:
- Validation: Is your product-market fit improving?
- Efficiency: Are your marketing dollars resulting in immediate traffic or sales spikes?
- Problem Detection: A sudden negative MoM rate can alert you to technical issues, seasonal slumps, or competitor actions.
- Compounding: Even small monthly growth rates compound significantly over a year. A consistent 5% monthly growth results in roughly 80% annual growth.
Understanding the Results
Positive Percentage: Indicates growth. The metric has increased compared to the previous month.
Negative Percentage: Indicates a decline or contraction. The metric is lower than the previous month.
Zero Percentage: The metric remained stagnant (flat) with no change.
Note: If your Prior Month Value is 0, the growth rate is mathematically undefined (often treated as infinite percentage growth if the current value is positive), as you cannot divide by zero.
function calculateGrowth() {
// Get input values
var priorVal = document.getElementById("priorValue").value;
var currentVal = document.getElementById("currentValue").value;
var resultBox = document.getElementById("result-box");
// Validate inputs
if (priorVal === "" || currentVal === "") {
resultBox.style.display = "block";
resultBox.className = "result-neutral";
resultBox.innerHTML = "
Please enter both the Prior Month and Current Month values.
";
return;
}
// Parse to floats
var prior = parseFloat(priorVal);
var current = parseFloat(currentVal);
// Check for NaN
if (isNaN(prior) || isNaN(current)) {
resultBox.style.display = "block";
resultBox.className = "result-neutral";
resultBox.innerHTML = "
Please ensure you enter valid numeric values.
";
return;
}
// Handle edge case: Divide by Zero
if (prior === 0) {
resultBox.style.display = "block";
resultBox.className = "result-neutral";
if (current > 0) {
resultBox.innerHTML = "
The metric grew from 0 to " + current + ". Mathematically, this is an infinite percentage increase.
";
} else if (current === 0) {
resultBox.innerHTML = "
Both months are 0. There is no growth or decline.
";
} else {
resultBox.innerHTML = "
Cannot calculate growth from a baseline of 0.
";
}
return;
}
// Calculate Formula: ((Current – Prior) / Prior) * 100
var diff = current – prior;
var growthRate = (diff / prior) * 100;
// Formatting
var formattedRate = growthRate.toFixed(2) + "%";
var formattedDiff = diff.toFixed(2);
// Determine style and message
var styleClass = "";
var icon = "";
var message = "";
if (growthRate > 0) {
styleClass = "result-positive";
icon = "▲";
message = "Growth";
} else if (growthRate < 0) {
styleClass = "result-negative";
icon = "▼";
message = "Decline";
} else {
styleClass = "result-neutral";
icon = "—";
message = "No Change";
}
// Display Result
resultBox.style.display = "block";
resultBox.className = styleClass;
var htmlContent = "";
htmlContent += "
";
htmlContent += "" + message + "";
htmlContent += "Absolute Change: " + (diff > 0 ? "+" : "") + formattedDiff;
htmlContent += "
";
resultBox.innerHTML = htmlContent;
}