CAGR Calculator: Find Your Growth Rate or Project Future Value

Most people reach for a CAGR calculator with one of two questions in mind. Either they already know what an investment grew from and to, and want the annual rate that explains it, or they know the rate they're hoping for and want to know what it turns into down the road. The same formula answers both, just rearranged. Here's how to use it either way, plus the mistake that quietly throws off more CAGR calculations than anything else.

What Our CAGR Calculator Actually Does

Our CAGR Calculator takes three inputs: your initial investment, its final value, and the number of years between them. It returns the Compound Annual Growth Rate, the single steady annual rate that would explain the whole journey from start to finish.

The formula underneath is:

CAGR = (Final Value / Initial Value)^(1/Years) - 1

If you want the full explanation of why this beats a simple average return, our guide on what CAGR actually measures covers that in depth. This one is about putting the number to work.

The Reverse Question: Projecting Future Value

Sometimes you're not looking backward at a completed investment, you're looking forward. You've got a starting amount and a rate you're assuming, and you want to know what it grows into.

That's the same formula, solved for a different variable:

Future Value = Initial Value x (1 + CAGR)^Years

Say you're starting with $15,000 and assuming a 9 percent annual return over 12 years.

$15,000 x (1.09)^12 = approximately $42,190

That's a hypothetical projection based on the assumed rate holding steady every year, which real markets rarely do. Treat it as a planning estimate, not a promise.

Comparing Two Investments Side by Side

Here's where a CAGR calculator earns its keep. Two funds, different starting points, different timeframes, and it's genuinely hard to tell which one actually performed better just by looking at the raw numbers.

Fund A: $5,000 grew to $9,200 over 6 years.

Fund B: $5,000 grew to $11,500 over 9 years.

Fund B has the bigger dollar gain, $6,500 versus $4,200. Run both through the CAGR formula, though:

• Fund A: (9,200 / 5,000)^(1/6) - 1 = approximately 10.70% per year
• Fund B: (11,500 / 5,000)^(1/9) - 1 = approximately 9.70% per year

Fund A actually grew faster on an annual basis. It just had less time to compound, so its total dollar gain looks smaller. Without converting both to CAGR, it's easy to give Fund B credit it hasn't really earned.

A Common Mistake People Make With CAGR Calculators

The single most common error is mixing up the time unit. If you have monthly data but enter the number of months where the calculator expects years, the result comes out dramatically wrong.

Take $10,000 growing to $14,000 over 3 years (36 months). Entered correctly as 3 years, the CAGR comes out to about 11.87%. Entered incorrectly as "36" (thinking in months but not converting), the calculator treats that as 36 years, and the result collapses to under 1%. Same investment, same real-world outcome, and a number that's off by more than tenfold purely from a units mismatch.

If your data is monthly, convert to years first (divide the number of months by 12), or convert your rate rather than mixing units mid-calculation.

Frequently Asked Questions

Can a CAGR calculator handle negative growth?

Yes. If your final value is lower than your initial value, the calculator returns a negative percentage, reflecting an average annual decline over the period.

Does it matter if I use months or years, as long as I'm consistent?

The calculator's time input is built around years, so convert months into years (or fractions of a year) before entering them, rather than typing the raw month count into a field expecting years.

Can I work out how long it'll take to reach a target amount?

That's a related but different calculation, solving for time rather than rate. If you have a starting amount, a target amount, and an assumed rate, you'd rearrange the formula to solve for years instead, which isn't what this specific calculator outputs directly.

Is CAGR the same as the annualized return my brokerage shows me?

Usually yes, in concept. Brokerages sometimes calculate it slightly differently depending on whether dividends, contributions, or withdrawals occurred during the period, so treat your CAGR calculator result as a clean baseline and your brokerage figure as one that may include those extra factors.

Try Both Directions

A CAGR calculator isn't just for looking backward at what already happened. The same formula works forward too, turning a target rate into a real dollar projection you can plan around.

Enter your own numbers into the CAGR Calculator to find a growth rate, or use the future value formula above to project where a starting amount and assumed rate could take you. If you'd rather run the math in a spreadsheet, our guide on calculating CAGR in Excel walks through the exact formula.

This article provides general educational information using hypothetical assumptions and isn't personalized financial advice. Actual investment returns vary and aren't guaranteed, so treat any projected figures as illustrations, not predictions.