Compound Growth Calculator

You can use this Compound Growth Calculator / Compound Interest Calculator to calculate how your investments and retirement capital might grow over time.

Tips for use: 

• Annual Contribution ($): The annual contribution amount does not increase with inflation, it stays constant across all years. 
• Inflation Rate (%): In the U.S., the Federal Reserve has an annual target inflation rate of 2%, though from ~1915 to present, the average annual inflation rate has been closer to 3%. *Note that this calculator uses the fisher equation to  factor in the compounding effect of real inflation.* 
• Compound Frequency: Be sure this is consistent with the numbers you are using. If you are entering an annual growth rate and annual inflation rate, having it compound annually would make sense. *Note that this calculator makes the annual contributions at the beginning of each compounding period.*
• 4% & 5% Withdrawal Rates: The calculator provides you with what the 4% and 5% withdrawal rates would be based on the total amount of principal accrued, factoring in inflation (showing you the future value in today’s dollars).

According to the “4% Rule”, ~4% is the amount that someone could “safely” withdraw each year from their (properly invested) investments with little to no chance of running out of money (i.e. bringing the principal amount to $0) over a ~30 year time horizon. The creator of the 4% Rule (Bill Bengen) has recently updated their findings and concluded that the modern/updated number is somewhere between 4% and 5% (close to 4.7%) (as of 2025).