What the calculator is actually trying to tell you.
Most retirement calculators answer a single question: do I have enough? They give you a confidence score and a thumbs-up. The answer feels precise. It is rarely useful, because the assumptions underneath the score are doing all the work, and they are hidden from you.
This calculator answers a different question: how does your plan change as the future changes? It runs your retirement under three different inflation futures, then layers Bitcoin on top of each one. The output isn't a confidence score. It's a shape — the age your plan covers to, the surplus or shortfall at your plan-through age, and the Bitcoin allocation that closes the gap.
The shape is the value. If your plan holds across all three futures, you're probably fine. If your plan only holds in the friendly future, you have a problem you can name. If it doesn't hold even in the friendly future, the issue isn't Bitcoin — it's your retirement age, your spending, or both. The calculator tells you which.
Three named inflation scenarios. Each one defended honestly.
You pick the future you find most plausible. Or, better, you stress-test against all three. None of these is a prediction. Each one is a planning model — a coherent argument about the next thirty years that you can either accept, partially accept, or reject. The math doesn't care which one you believe. It just shows you what your retirement looks like inside it.
The argument: AI productivity gains are real, broad, and absorbed into the economy. Software, healthcare, education, and energy all see meaningful cost reductions over the next fifteen years. Real wage growth resumes. Fiscal pressure eases because GDP outpaces debt. Inflation settles near the Fed's stated 2% target.
What changes: Healthcare costs drop as diagnostic AI replaces the most expensive specialist visits. Energy costs fall via cheaper compute, better solar, and improving storage. Education and elder-care, the two stubborn lines, finally start to bend. Stocks do well because productivity translates into earnings. Bonds recover from the 2022-2024 reset.
The risk if you believe this: You don't own enough productive assets — including Bitcoin — to benefit from the boom. The household that keeps too much in cash watches the world get cheaper while their savings sit still. In a bull case, the bigger risk is conservatism.
The argument: Inflation is sticky but manageable. Roughly 3 to 3.5% headline, with healthcare and education running a point or two higher. The Fed maintains its 2% target as policy but accepts modest overshoots. AI helps at the margin but doesn't bend the curve on the components that matter most for retirees.
What changes: Not much, dramatically. The fiscal deficit remains a slow drag. Demographic spending pressure rises gradually as more boomers enter expensive late-life care. Energy and food repricing happens in lurches, not waves. Most years feel normal. A few years remind everyone that inflation isn't fully tamed.
The honest position: This is what most official models use. It is also probably wrong, but in a politely calibrated way — wrong by maybe a point either direction, not wrong by a regime change. The middle is plausible because the middle usually is. This is the default for a reason.
The argument: Persistent 4.5 to 6% inflation driven by demographic spending pressure, interest expense as a share of GDP exceeding defense spending, and structural deficits that the bond market starts refusing to absorb. The Fed loses control of the long end of the curve. Energy and food reprice higher because of geopolitical fragmentation. Healthcare and elder-care, already running hot, get worse.
What changes: Stocks struggle because cost of capital rises and margins compress. Real returns on bonds turn negative for years at a time. The dollar weakens. Property taxes rise faster than incomes. Anyone whose retirement plan assumes 2% inflation breaks somewhere between age 78 and 84.
What this case asks of you: Not a prediction. A stress test. If your plan can survive this scenario, you can survive most of the others. If it can't, the math is telling you something the headlines aren't.
Year by year, in today's dollars.
The calculator runs a deterministic simulation from your current age to your plan-through age. Every value in the simulation is kept in today's dollars. Your spending stays steady at the number you entered. Your assets grow at a modest real return — meaning the return you actually earn after inflation, not the headline return. Pension payments lose value over time where the COLA doesn't keep up with inflation. Social Security is assumed to track inflation fully because that's how it's legally structured.
The simulation steps through each year of your retirement. Income from Social Security and pension covers what it can. The remaining spending gets pulled from your investable assets — first from the non-Bitcoin portion, then from the Bitcoin position if that runs out. If the assets last to your plan-through age with a positive balance, you have a surplus. If they don't, the engine notes the year the plan broke.
Bitcoin gets one number in your hands: the percentage allocation you target at retirement. The engine computes how much Bitcoin you'd need in coin terms to hit that percentage of your total portfolio at retirement age, and how much you'd need to accumulate per month between now and then to get there. The monthly stack is a planning number, not a recommendation.
The locked assumptions
These are the parameters you can change on the calculator page, plus a few you can't (yet):
| Variable | Default |
|---|---|
| Plan-through age | 100 years old |
| Bitcoin real return | 7% per year |
| Traditional real return (base case) | 3.5% per year |
| Traditional real return (bull case) | 4.5% per year |
| Traditional real return (bear case) | 2.0% per year |
| Pension COLA (default) | 3% per year, compounded |
| Social Security indexing | Full inflation adjustment |
| Bitcoin spot price (for coin conversion) | $95,000 |
| Withdrawal order | Non-Bitcoin first, then Bitcoin |
The 7% Bitcoin real return is conservative relative to historical performance. The 3.5% traditional real return is roughly in line with long-run equity-bond blends after inflation. Both numbers are defensible as planning assumptions. Neither is a prediction.
The honest list of skipped complexity.
Most retirement calculators hide their limitations. This one names them. If any of these matter to you — and several of them probably do — the calculator's answer is a planning shape, not your actual answer.
- It doesn't run thousands of random futures. Real planning software runs a few thousand simulated paths through your retirement and reports the percentage that succeed. This one runs a single deterministic path under a single inflation assumption. You stress-test by running it under all three named scenarios manually. That's the trade-off — simpler, more legible, less precise.
- It doesn't model the order you'd actually pull money from accounts. In real life, you'd pull from taxable accounts first, then traditional 401(k)/IRA, then Roth — to minimize taxes. The calculator treats your "investable" balance as one bucket. The total math is roughly right; the tax efficiency is naive.
- It doesn't model the healthcare bridge from retirement to Medicare. If you retire at 62, you'll pay ACA marketplace premiums or COBRA for three years — typically $15,000 to $25,000 per year per person on top of normal spending. The calculator doesn't add this. Mentally include it if it applies.
- It doesn't model a long-term care spike in your eighties. Memory care, assisted living, or in-home care can run $80,000 to $150,000 per year for the last several years of life. The calculator assumes your spending stays flat in real terms throughout retirement. It doesn't.
- It doesn't separately track two spouses with two income histories. Your Social Security and your spouse's are summed into one household number. Your retirement ages are treated as one. For roughly accurate planning this is fine; for couples with very different timelines or earnings histories, it's an oversimplification.
- It doesn't model market timing or sequence-of-returns risk. In real life, if the market drops 30% the year you retire, your plan is in much worse shape than if it drops 30% ten years in. The deterministic engine averages this away. The bear case is the stand-in.
None of these are deal-breakers for the calculator's value. They are reasons to treat the output as a shape, not a number. If the calculator says your plan covers to age 92 in the base case, the honest interpretation is "probably late eighties, depending on what life does to you." If it says you run out at 78 in the bear case, the honest interpretation is "this is the case to plan around."
One asset. Five allocations. No predictions.
The calculator adds exactly one asset to the standard retirement math: Bitcoin. It does this for two reasons.
The first is structural. Most retirement plans are built from the same three or four inputs — 401(k), Social Security, pension, home equity. The calculator can't help you with most of those; they are what they are. What it can help with is the marginal question: does a small amount of a different kind of asset change my outcome? Bitcoin is the most argued-about candidate for that question right now. It's where mainstream financial advice has started recommending small allocations. It's where this audience already has questions.
The second is honesty. The calculator's job is not to convince you Bitcoin is good. Its job is to show you what changes if you add 3%, 5%, 10%, or 20% to your portfolio at retirement. For some households, 5% closes the gap. For others, it barely moves the needle. For some, even 20% can't fix a structural spending or timing problem. The math tells you which case you're in.
The Bitcoin price model is the part of the calculator that does the most work. It uses the Bitcoin Power Law — a statistical curve that fits Bitcoin's daily price history with 95.65% accuracy since 2009 — through the adoption phase, then caps it at 10% of projected global personal wealth to prevent the model from assuming Bitcoin captures an impossible share of the world's economy. The full reasoning is on the Power Law page.
This is a deliberately conservative choice. Most Bitcoin advocates would model higher returns. The calculator stays conservative because its job is to be defensible against a financial planner who asks where the numbers came from — not to make Bitcoin look good. If you believe Bitcoin will compound faster than the capped model implies, your retirement gap closes sooner than the calculator suggests. If you believe it will underperform, the gap closes more slowly. The conservative default protects against both kinds of overconfidence.
The honest version.
Every retirement calculator is wrong about your future. The ones that pretend otherwise are wrong twice. The future doesn't run on a single inflation rate or a single return assumption. It runs on whatever actually happens, and the actually-happens is unknowable. The best a calculator can do is show you the shape of your plan under a few coherent versions of the future, and let you stress-test the parts you find most plausible.
That's what this one does. It runs your numbers under three named futures. It tells you what happens to your plan in each. It lets you add one variable — Bitcoin — and see if it changes the answer. It doesn't tell you what to do. It shows you what your situation looks like clearly enough that you can decide.
If you want a financial plan, hire a financial planner. They will do all the things this calculator skips — tax-aware withdrawal ordering, multi-asset Monte Carlo, healthcare bridge, long-term care, estate planning, the works. They will also charge you several thousand dollars for the privilege, and the answer they give you will still depend on assumptions about the future that nobody can verify.
Now run your numbers.
The calculator is one click away. Your inputs never leave your laptop.