Index Investing Scenario Explorer

Explore how your assumptions change long-term balances. This free calculator compares costs, inflation, doubling time and a hypothetical downturn. It also includes separate, simplified contribution tax examples. It does not select investments or predict returns.

Start with our Bogleheads investing guide, Rule of 72 and 401(k) example, or HSA medical-reserve guide.

Open the free calculator in its own window for saving and printing