How the retirement planner works

Start with your current Bitcoin holdings, current age, retirement age, monthly contributions, and desired annual spending in today’s dollars. Set the number of retirement years you want to fund. All results are illustrative scenarios, not forecasts.

One timeline, from today through retirement

The first row represents today, with no growth or contributions applied. Each subsequent row follows 12 months of growth and end-of-month purchases. Contributions stay constant in dollars and stop when retirement starts. Annual withdrawals begin at retirement and are capped at available holdings. Every displayed portfolio balance is after withdrawals.

Growth assumptions

Choose flat growth, a 5% annual decline, a custom fixed rate, a custom declining rate, or one of the seven original schedules. The original schedules are illustrative rate arrays, not fitted forecasting models. Even M4 starts at 24% growth. The old labels, including “Conservative” and “Baseline,” should not be interpreted as safety ratings. The full rate table is available on the calculator. Its first rate applies to the year after today; its final rate continues after 30 growth years.

Spending, inflation and taxes

The annual spending goal is entered in today’s dollars and rises with inflation from today, including before retirement. The main annual-income summary converts results back to today’s purchasing power. Set inflation to zero for a constant dollar target. Tax is a simplified effective rate applied to the entire withdrawal, not a capital-gains calculation with cost basis. All three withdrawal strategies are evaluated against the after-tax spending target.

Three withdrawal strategies

Fund my spending target sells enough Bitcoin to meet the inflation-adjusted target after tax, limited by available funds. Fixed percentage sells a chosen share of remaining holdings annually. Changing percentage moves from your starting rate to your ending rate over the retirement years. With a single retirement year, the starting rate is used. A positive remaining balance does not count as success if the income is below your target.

Reading the goal summary

Bitcoin needed today searches for the initial holdings that fund the spending target with your contributions unchanged. This measure uses spending-target withdrawals regardless of your selected strategy. Earliest funded retirement searches from your current age through age 100 using your selected strategy and retirement duration. Neither measure predicts a real retirement date.

Comparisons and stress tests

Compare extra contributions, reduced spending, or a later retirement without changing your original inputs. A crash replaces the annual growth at retirement with a 50% loss; for immediate retirement it occurs the following year. The flat scenario replaces the next five growth years with zero growth. The inflation scenario adds two percentage points, capped at 20%. Each comparison changes one assumption at a time. Later retirement also moves the end of the retirement period, so ending balances refer to different years.

Simulation methodology

The simulation uses the same calculation engine and timeline as the table. It runs 1,000 paths with independent lognormal annual returns and a 65% log-return volatility assumption. The mean gross return is set to the selected model’s gross return. There is no historical backtest or correlation model. A fixed random seed makes results repeatable. Success means meeting the spending target after tax in every retirement year. The 10th, 50th and 90th portfolio percentiles are measured separately at each year, not complete individual paths or guaranteed ranges.

Save, share and export

Save on device stores one plan in this browser. Load saved plan restores it; saving again replaces it. Shared links include the entered financial figures in the URL fragment. CSV and PDF downloads include calculation assumptions and annual results. Nothing is saved to an account. The simulation is illustrative and is not included in the deterministic exports.

Limits of this release

The planner does not include other assets, benefits, other income, trading fees, cash reserves, cost basis, or flexible spending rules. Purchase prices within each year follow a smooth monthly path implied by that year’s return. Real prices do not behave that way. Annual withdrawals approximate spending timing. Explore multiple assumptions rather than relying on one result.