How to Use the Investment Goal Calculator
One of the most common investing questions is: "How long will it take to reach my financial goal?" This calculator uses compound interest math to tell you exactly how long your current principal needs to grow at a given annual return rate to hit your target.
Calculation Formula
Years = log(Target ÷ Principal) ÷ log(1 + Annual Return ÷ 100). This assumes compounding at the stated annual rate with no additional contributions. For goals with regular contributions, use a compound savings calculator instead.
Realistic Return Rate Assumptions
The S&P 500 has returned roughly 10% annually over the long term (about 7% after inflation). A diversified stock/bond portfolio might average 6-8%. For conservative planning, 5-6% is often used. Remember: past performance doesn't guarantee future results.
The Rule of 72
For a quick estimate, divide 72 by your expected annual return to find roughly how many years it takes to double your money. At 8% return: 72 ÷ 8 = 9 years. This calculator gives you the precise figure for any target, not just 2x.
Frequently Asked Questions
No, this calculator uses nominal (pre-inflation) returns. To account for inflation, subtract your expected inflation rate from the annual return. For example, if you expect 8% return and 3% inflation, use 5% as your real return rate.
This calculator assumes no additional contributions beyond the initial principal. Regular monthly or annual contributions would significantly reduce the time needed. Use a compound savings calculator to model that scenario.