function calculateMonthlyGrowth() {
// Get inputs using var
var startVal = parseFloat(document.getElementById('startValue').value);
var endVal = parseFloat(document.getElementById('endValue').value);
var months = parseFloat(document.getElementById('periodMonths').value);
var resultBox = document.getElementById('resultOutput');
// Basic validation
if (isNaN(startVal) || isNaN(endVal) || isNaN(months)) {
alert("Please enter valid numbers for all fields.");
resultBox.style.display = "none";
return;
}
if (startVal === 0) {
alert("Beginning Value cannot be zero for growth calculations.");
resultBox.style.display = "none";
return;
}
if (months 0 && startVal > 0) {
cmgr = (Math.pow((endVal / startVal), (1 / months)) – 1) * 100;
} else {
// Fallback for cases where power formula doesn't apply well (e.g. crossing zero)
// We will display the simple average arithmetic growth
cmgr = totalGrowth / months;
}
}
// Display Results
resultBox.style.display = "block";
// Update DOM
var cmgrElem = document.getElementById('cmgrResult');
var totalElem = document.getElementById('totalPercentResult');
var diffElem = document.getElementById('absDiffResult');
cmgrElem.innerText = cmgr.toFixed(2) + "%";
totalElem.innerText = totalGrowth.toFixed(2) + "%";
diffElem.innerText = diff.toLocaleString(undefined, { minimumFractionDigits: 0, maximumFractionDigits: 2 });
// Styling for positive/negative
if (cmgr >= 0) {
cmgrElem.className = "result-value";
cmgrElem.style.color = "#27ae60";
} else {
cmgrElem.className = "result-value negative";
cmgrElem.style.color = "#c0392b";
}
if (totalGrowth >= 0) {
totalElem.className = "result-value";
totalElem.style.color = "#27ae60";
} else {
totalElem.className = "result-value negative";
totalElem.style.color = "#c0392b";
}
}
How to Calculate Monthly Growth Rate
Calculating your monthly growth rate is essential for tracking the momentum of your business, website traffic, or investment portfolio. Whether you are analyzing Month-over-Month (MoM) growth or determining a Compound Monthly Growth Rate (CMGR) over a longer period, understanding these metrics helps in making data-driven decisions.
Why Measure Monthly Growth?
Monthly growth metrics provide a granular view of performance that annual reports often miss. They are particularly vital for:
Startups & SaaS: Investors look for consistent CMGR to validate product-market fit.
Marketing: Tracking monthly traffic or lead generation improvements.
Sales: Monitoring revenue trends to adjust forecasts quickly.
Method 1: Simple Month-over-Month (MoM) Growth
If you are comparing two consecutive months (e.g., January revenue vs. February revenue), you use the simple growth formula. Set the "Time Period" in the calculator to 1.
Growth Rate = ((Present Value – Past Value) / Past Value) × 100
Example: If you had 1,000 users in Jan and 1,200 in Feb, your growth is ((1200 – 1000) / 1000) × 100 = 20%.
Method 2: Compound Monthly Growth Rate (CMGR)
When you want to find the average monthly growth rate over a longer period (e.g., from January to June), a simple average can be misleading. CMGR calculates the steady monthly rate required to get from the starting value to the ending value, accounting for compounding.
CMGR = (Ending Value / Beginning Value)^(1 / Number of Months) – 1
Example: If you started with $1,000 revenue and ended 6 months later with $5,000:
Beginning Value: 1,000
Ending Value: 5,000
Period: 6 Months
Result: Approx 30.77% monthly compounded growth.
Interpreting the Results
A positive percentage indicates growth, while a negative percentage indicates a decline (churn or loss). While high growth rates are desirable, consistency (low volatility) in your CMGR is often a better indicator of long-term health for established businesses.