Investing tools

Free calculators for growing your money — compounding, dividends, fees, and taxes. When you are ready to pick investments, they hand off to Investor Sam's stock analysis and Ask Sam.

23 resources

Calculator Coast FIRE Number Calculator Find the lump sum you need saved today to stop contributing and let compound interest carry you to retirement. Open → Calculator Compound Interest Calculator with Monthly Contributions See how your starting balance, monthly contributions, and annual increases interact to build wealth over decades. Open → Calculator Daily Habit Invested Calculator Redirect a small daily spend to investments and see the after-tax wealth it builds over 20 or 30 years. Open → Calculator Dividend Reinvestment Snowball Calculator Model how automatically reinvesting dividends compounds your share count and total wealth over decades. Open → Calculator Dollar-Cost Averaging vs. Lump Sum Compare investing a windfall all at once versus spreading it out monthly — and see which strategy wins for your scenario. Open → Calculator Emergency Fund: HYSA vs. Checking Account Calculate how much interest you forfeit by keeping your emergency fund in a low-yield checking account. Open → Calculator Expense Ratio Fund Comparison Compare two funds side by side to see exactly how many years of contributions the higher-fee fund will cost you. Open → Calculator Fund Fee Drag Calculator Discover how much a 1% expense ratio silently destroys over 30 years compared to a low-cost index fund. Open → Calculator Inflation Purchasing Power Calculator See what today's dollars will be worth in the future and how much return you need just to stay even with inflation. Open → Calculator Market Drop Recovery Calculator See how long it takes to break even after a market crash — and the hidden growth you forfeit during the recovery. Open → Calculator Minimum Payment Trap Calculator See how credit card minimum payments multiply your debt burden and how much you save with a fixed monthly payment. Open → Calculator Opportunity Cost of Waiting to Invest See the permanent wealth gap created by waiting 5 or 10 years before investing — a gap that never fully closes. Open → Calculator Real Return After Inflation and Taxes Reveal what you actually keep: your nominal investment return minus inflation and capital gains taxes. Open → Calculator Rebalancing Bonus Calculator Discover the extra return that annual rebalancing can add versus letting your portfolio drift unchecked. Open → Calculator Roth vs. Traditional IRA Calculator Find out whether to pay tax now or in retirement — and the exact break-even tax rate where both options tie. Open → Calculator Rule of 72 — How Fast Will Your Money Double? Use the Rule of 72 to estimate when your investment doubles, and see exactly how many doublings fit in your horizon. Open → Calculator Savings Rate to Financial Independence Enter your income and expenses to find out exactly how many years until you reach financial independence. Open → Calculator Sequence of Returns Risk Calculator See how identical average returns produce radically different retirement outcomes when bad years hit early versus late. Open → Calculator Target-Date Fund vs. DIY Portfolio Cost See how much a target-date fund costs over a lifetime compared to an equivalent three-fund DIY portfolio. Open → Calculator Tax Drag of High-Turnover Funds Calculate how fund turnover rate silently taxes your returns annually and costs you thousands over a lifetime. Open → Guide How a 1% Fee Quietly Steals a Third of Your Retirement A 1% annual fee sounds trivial, but compounded over a career it can erase a third of your nest egg — here is the math, and how to check what you are really paying. Open → Guide The Cost of Waiting to Invest: Why Starting Today Beats Timing the Market Waiting for the "right time" to invest has a hidden price tag — here is the exact dollar cost of delay, and why starting now beats a perfectly timed entry. Open → Guide What Is Coast FIRE — and How Do I Know If I've Hit It? Coast FIRE means you have invested enough that your portfolio can grow to full retirement on its own — here is how to calculate your number and know when you have reached it. Open →