function calculateGrowthRate() {
// Get input values using var
var startValue = parseFloat(document.getElementById('startVal').value);
var endValue = parseFloat(document.getElementById('endVal').value);
var periods = parseFloat(document.getElementById('periodCount').value);
var resultsDiv = document.getElementById('results');
// Validation
if (isNaN(startValue) || isNaN(endValue) || isNaN(periods)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (startValue === 0) {
alert("Starting value cannot be zero for growth rate calculations.");
return;
}
if (periods <= 0) {
alert("Number of periods must be greater than zero.");
return;
}
// 1. Calculate Absolute Difference
var absDiff = endValue – startValue;
// 2. Calculate Total Percentage Growth (Simple Growth)
// Formula: (End – Start) / Start
var totalGrowthDec = (endValue – startValue) / startValue;
var totalGrowthPct = totalGrowthDec * 100;
// 3. Calculate CAGR (Compound Annual Growth Rate)
// Formula: (End / Start)^(1/n) – 1
var cagrDec = Math.pow((endValue / startValue), (1 / periods)) – 1;
var cagrPct = cagrDec * 100;
// Update HTML
document.getElementById('cagrResult').innerHTML = cagrPct.toFixed(2) + "%";
document.getElementById('totalGrowthResult').innerHTML = totalGrowthPct.toFixed(2) + "%";
document.getElementById('absDiffResult').innerHTML = absDiff.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Show results
resultsDiv.style.display = "block";
}
How to Calculate Growth Rates in Excel
Calculating growth rates is essential for analyzing financial performance, tracking investment returns, or monitoring user acquisition. While the calculator above provides an instant solution for Compound Annual Growth Rate (CAGR) and simple percentage growth, knowing how to perform these calculations in Microsoft Excel is a critical skill for any analyst.
1. The Basic Growth Formula (Month-over-Month or Year-over-Year)
The simplest form of growth rate measures the percentage change between two numbers. This is often used for calculating revenue growth from one year to the next.
Example: If your revenue was 100 in A1 and is 120 in B1, the formula is =(B1-A1)/A1. Format the cell as a percentage to see 20%.
2. Calculating Compound Annual Growth Rate (CAGR) in Excel
CAGR is the most accurate way to determine the constant growth rate of an investment or business metric over a specific period of time greater than one year. It smooths out the volatility of periodic returns.
Method A: Using the Mathematical Formula
You can type the CAGR formula directly into an Excel cell. The syntax mirrors the logic used in our online calculator:
Excel has a built-in function specifically for this calculation called RRI. This function returns an equivalent interest rate for the growth of an investment.
Syntax: =RRI(nper, pv, fv)
nper: The number of periods (years).
pv: Present value (Starting value).
fv: Future value (Ending value).
3. Calculating Average Annual Growth Rate (AAGR)
While CAGR measures the geometric progression ratio, AAGR is the arithmetic mean of a series of growth rates. This is useful for seeing the "average" trend, though it doesn't account for compounding effects.
Calculate the growth rate for each individual year (e.g., Year 1 to Year 2, Year 2 to Year 3).
Use the =AVERAGE() function in Excel to find the mean of those percentages.
Common Errors to Watch For
#DIV/0!: This occurs if your Start Value is 0. Growth rates cannot be calculated mathematically if the baseline is zero.
#NUM!: This may appear in CAGR calculations if you try to calculate growth over a negative number of periods or if the base values are negative (depending on the Excel version and formula used).
Formatting: Always remember to click the "%" button in the Home ribbon after entering your formula, otherwise, you will see a decimal like 0.14 instead of 14%.
Use the tool at the top of this page to double-check your Excel work and ensure your growth projections are accurate.