15 free calculators

Free calculators for index investing and financial independence

Thirteen interactive tools covering the full arc: understanding compound growth and fees, deciding your allocation, executing your plan, and figuring out when you can live off your portfolio.

Free, no sign-up
Work offline
No data leaves your browser
Printable

Where should I start?

1 I'm starting from zero What an index fund is and how to build your first portfolio, step by step. 2 I already invest, I want to optimize Rebalancing, fees, and the split between stocks and bonds. 3 I'm approaching living off my portfolio How much to withdraw safely and when you can stop contributing.

Interactive calculators 15 tools

Grouped in the order a new investor actually needs them: first understand the terrain, then decide your portfolio, execute the plan, and finally figure out when you can live off it.

Understand 5

The terrain: what time does to your money, and what each fee actually costs you.

CalculatorUnderstand Compound Interest Calculator Year by year, how much you put in versus how much the market generated — in today's dollars, inflation-adjusted. Open calculator CalculatorUnderstand Savings Goal Calculator The monthly contribution you need to reach any goal — a down payment, tuition, your first million. Open calculator CalculatorUnderstand Investment Fee Impact Calculator What the silent partner takes from your portfolio. Compare two expense ratios and see the gap compound over 25 years. Open calculator SimulatorUnderstand Historical Returns Simulator What actually would have happened, using real annual returns — and how much the outcome changes just by starting one year later. Open simulator CalculatorUnderstand Inflation Calculator How much purchasing power your money loses if idle, and how much it gains if invested. Open calculator

Decide 3

Design your portfolio: how much in stocks, and how it plays out over time.

CalculatorDecide Asset Allocation Calculator How much in stocks and how much in bonds. Set by the tighter of two limits: your time horizon and the drawdown you could stomach without selling. Open calculator SimulatorDecide Portfolio Projector Stock/bond allocation is the one decision that really matters. Compare allocations, including a bad sequence of years. Open simulator CalculatorDecide Pre-Tax vs Taxable Account Calculator Pre-tax, tax-free or taxable account? Enter your tax rate today and in retirement and see which one leaves you with more. Open calculator

Execute 2

Put the plan into motion and keep it running when your portfolio drifts off target.

CalculatorExecute DCA vs. Lump Sum Calculator Invest it all at once or spread it out: what the evidence actually says, with real numbers. Open calculator CalculatorExecute Portfolio Rebalancing Calculator If your weights have drifted, when it's time to rebalance and by how much. Open calculator

Independence 5

When you can stop working for money, and how much you can safely withdraw.

CalculatorIndependence FI Number Calculator How much capital you need to live off your portfolio, based on your annual spending and the withdrawal rate you choose. Open calculator CalculatorIndependence Time to FI Calculator How many years are left? The answer depends mostly on your savings rate — not on your returns. Open calculator CalculatorIndependence Coast FIRE Calculator The point where you can stop contributing and still get there — compound growth finishes the job on its own. It usually happens earlier than people think. Open calculator SimulatorIndependence Safe Withdrawal Rate Simulator How much can you withdraw per year without running out of money? Stress-test your plan against nearly a century of real market history. Open simulator CalculatorIndependence FIRE With a State Pension How much capital you really need if you will receive a state pension, and what the bridge years until it starts cost. Open calculator

These 15 tools cover everything that isn't country-specific. The Spanish site has 22 tools in total — the other 7 handle Spanish tax rules (capital gains, tax-loss carryforwards, pension plans) and only make sense for investors filing taxes in Spain.

See all 22 tools (in Spanish) →

NewDownloadable · yours to keep

Track your portfolio from your own computer

Log every contribution, see how far you have drifted from your target weights and measure your real money-weighted return. It is a single file you download and keep: it opens with a double click, works offline, and your figures never leave your machine.

No account, no sign-up
Works without internet
Rebalance without selling
30-year projection

Open the tracker

Try it here, then download it from inside

These tools are a free companion to a book — just not in English yet

Fondos indexados is a Spanish-language book on passive index investing, written for investors filing taxes in Spain. These 13 calculators are the country-agnostic subset of its companion toolkit, released here for anyone to use for free.

See the book (in Spanish) →