Start from one of the household setups, or skip the story and run yours cold. Everything updates as you type. Nothing leaves your laptop.
Every field changes the math on the right in real time. Fields are pre-loaded from the household you picked — change anything you want.
Local-first. Nothing leaves your laptop. Saved to your browser.
Same inputs above. Only Bitcoin allocation changes.
| Allocation | Plan to | Surplus / shortfall | BTC needed | Monthly |
|---|
What it does: A deterministic year-by-year simulation of your retirement in today's dollars. Real returns on assets, real-value tracking on pension and Social Security (with COLA losses applied where COLA lags inflation), drawdown that's tax-naive but spending-honest. Bitcoin is one variable. The output is the age your plan covers to, the surplus or shortfall at your plan-through age, and the BTC accumulation required to close the gap.
What it doesn't do: Monte Carlo simulation, sequence-of-returns risk, tax-aware withdrawal ordering, market timing, custom long-term care windows, multiple income sources per spouse, or anything that requires interviewing you for an hour. It is a planning estimate, not a financial plan. Take the answer as a shape, not a number.
The honest version: Every retirement calculator is wrong about your future. The ones that pretend otherwise are wrong twice. This one shows you whether your plan holds under three named inflation futures and one Bitcoin variable. The shape is the value.
The accurate way: Log in to ssa.gov and look at your latest statement. It estimates your monthly benefit at 62, full retirement age, and 70. Multiply the FRA number by 12.
The quick way (rough estimate, for planning only):
The cap matters: even high earners max out around $54K/year at full retirement age (2026 figures). The system is progressive at the top.
Not sure? Leave it at 0 and rerun later. The plan will look worse than it really is — which is fine for a stress test.