What this category covers
This category focuses on growth, return, and investment-planning calculators.
Investing tools
Investing Calculators
Estimate how compounding, returns, and time can influence portfolio growth and long-term investing decisions.
Common calculator topics
This category includes ROI, retirement, CAGR, dividend income, and portfolio growth topics.
Available now
5 live calculators in this category, with each tool built as a dedicated page for easier comparison and revisits.
How to use these calculators
Investing decisions involve time, return assumptions, and compounding in ways that are hard to estimate intuitively. A sum invested today grows differently depending on the rate of return, contribution frequency, time horizon, and whether gains are reinvested. Small differences in those inputs can produce dramatically different outcomes over a long period.
This hub focuses on long-term growth estimation. The tools here are designed to help you understand how compounding and time interact — not to predict what any investment will actually return. Markets are uncertain, and a calculator can only show what a given rate would produce, not what rate you should expect.
Use these calculators to frame decisions rather than finalize them. A retirement savings projection shows whether your current pace may be sufficient for a given goal. A Coast FIRE calculator shows whether accumulated savings might grow to a target without additional contributions. An inflation-adjusted return shows how purchasing power, not just dollar amount, may change over time.
Who this is for
- People projecting long-term portfolio growth at a given return and contribution rate.
- Anyone trying to understand how compounding changes across different time horizons.
- Savers estimating whether their current retirement savings pace is on track for a goal.
- People trying to account for inflation when thinking about the future value of money.
Common decisions this helps with
- How much a lump sum or recurring investment might grow over a set period.
- Whether the current savings rate is likely sufficient for a retirement or FIRE target.
- How inflation may reduce the real value of a future dollar amount.
- How long it may take for an investment to double at a given annual return rate.
Choose the right calculator
Project compound growthUse the interest calculator to see how a lump sum or recurring contribution may grow at a given return over time.Estimate retirement savingsUse the retirement savings calculator when you want to project whether current contributions may reach a retirement target by a given age.Find your Coast FIRE numberUse the Coast FIRE calculator to estimate whether existing savings could grow to a retirement target without additional contributions.Adjust returns for inflationUse the inflation-adjusted return calculator to translate a nominal return into a real return that accounts for purchasing power change.
Choose a calculator
Start with a focused estimate, then move to related calculators when you need to compare the next part of the decision.
Start here
These calculators are the clearest entry points for this category.
Interest CalculatorQuickly estimate how compound interest changes borrowing costs or account growth.Retirement Savings CalculatorProject retirement savings growth with ongoing contributions and compound returns.Coast FIRE CalculatorEstimate the investment balance needed now to let compounding carry you to retirement without future contributions.Inflation Adjusted Return CalculatorConvert nominal investment growth into real, inflation-adjusted returns and ending value.
Category questions
What return rate should I use in these calculators?
There is no guaranteed rate. Common planning assumptions range from 5% to 8% for diversified portfolios, but actual returns vary by asset mix, time period, and market conditions. Try multiple rates to see a range of outcomes instead of relying on one assumption.
What is the Rule of 72?
The Rule of 72 estimates how long an investment takes to double. Divide 72 by the annual return rate. At 6%, money roughly doubles in 12 years. It is a quick approximation useful for comparing scenarios, not a precise guarantee.
What is Coast FIRE?
Coast FIRE refers to a point where existing savings are expected to grow to a retirement target by a given age without any further contributions. The Coast FIRE calculator estimates how much you need saved today to reach that point.
Do these calculators account for taxes or investment fees?
Most use simplified assumptions and do not deduct fund expenses, advisory fees, or capital gains taxes. Those costs can meaningfully affect long-term outcomes and are worth considering alongside any estimate.