A thinking tool, not financial advice · assumptions dated —
What if the cost of living has a curve?
Traditional planning software asks what your life costs today, assumes it costs the same (after inflation) every year until you die, and hands you one precise-looking number. That worked when the world's prices moved together. It may be exactly wrong in an age when some costs are collapsing on exponential curves while others keep climbing. This tool lets you split the difference honestly: your numbers, your assumptions, every one of them visible and adjustable — and a range instead of a false-precise answer.
Read this first — what this tool is, and is not
This is not financial advice, and it is not a plan. It is a thinking tool built on a thesis — that some costs may fall much faster than official long-run forecasts assume — and a thesis can be wrong. Nothing here recommends that you save less, spend more, give money away, buy anything, or change any financial decision. The deflation modeled here may simply not happen; the timelines are contested by serious people; and every output inherits whatever error lives in your inputs and in our assumptions. For decisions about your actual money, talk to a qualified, licensed professional who knows your situation. What this tool offers is one thing only: a transparent way to see how different assumptions about the future change the picture — including the assumption that nothing changes at all.
Your numbers
All in today's dollars. The prefills sketch a typical household — replace them with yours. Nothing is stored or sent anywhere; reload the page and it's gone.
Money
"Real return" means after inflation. The modest default is a thesis choice, not a forecast — set your own. While you're still working, the model assumes income covers your living costs and only your monthly saving moves the balance; from your stop-work age on, spending draws from savings. (A simplification, stated plainly.)
What your life costs, by category
The tags matter: sticky categories have historically risen faster than inflation; deflating ones have fallen. The model treats them separately — that split is its whole point.
The world model — your assumptions, not ours
Three dials govern everything. Each has a default and a source; none of them is a fact about the future, because nobody has one of those.
The anchor year — when the handoff centers
Each category's rate ramps from its historical reading toward its "mature abundance" rate along an S-curve centered here. The default, 2045, is Ray Kurzweil's famous Singularity date — a contested guess, which is why it's a slider. Aggressive forecasters say early 2030s; diffusion skeptics like Acemoglu say decades later, or never. Drag it to your own view.
The caution dial — for margin-lovers
Doubt the good news without touching the bad: this divides every deflation rate while keeping every sticky increase in full. At "Traditional" the curve disappears entirely and this becomes an ordinary retirement calculator — a setting we respect, not a strawman.
Pessimistic — the curves stall
Handoff 12 years later and weaker; deflation at half strength; sticky costs never relent. Note it can read worse than the traditional plan — if abundance doesn't come and care costs keep climbing, the old static math was too rosy, not too grim.
Base — the thesis as modeled
Exactly the assumptions in the table below, with your dials. Not a prediction — the midpoint of a guess.
Optimistic — the curves compound
Handoff 7 years earlier and faster, mature deflation 30% stronger — the world the aggressive forecasters describe.
All three run on every calculation, always shown together. A runway is a range. Any tool that hands you one number about 2050 is expressing confidence nobody has.
What the model sees
A range from a thesis-model — not a prediction, and not a plan. Change anything above and everything below moves.
How long the money lasts
four answers on purpose — one would be false precisionSpending tier used for the runway:
What your basket costs, year by year
Annual cost of the life you priced above, in today's dollars, under each scenario. The dashed gray line is the traditional planner's assumption: no curve at all.
Your savings balance
Balance in today's dollars. A dot on the floor marks the age money runs out under that scenario.
Three tiers of the same life
Your basket at three intensities, priced by the base scenario. The question this table asks quietly: which tier were you assuming you had to fund forever — and what does the curve do to the gap between them?
| Tier | Cost/yr today | In 2045 | In 2060 | What it means |
|---|
Year-by-year detail (base scenario vs traditional)
| Year | Age | Basket $/yr (base) | Balance (base) | Balance (traditional) |
|---|
Every assumption, on the table
Two kinds of numbers drive this tool, and we refuse to blur them. The "last ~25 yrs" column is history — real (inflation-adjusted) annual rates, each traced to a named public source. The "mature thesis" and "floor" columns are guesses — ours, labeled as such, and editable because your guess has the same legal standing as ours: none. Edit any cell and the whole tool recomputes.
| Category | Real %/yr, last ~25 yrs history, sourced |
Mature %/yr our thesis — a guess you can edit |
Cost floor thesis — × today's cost |
Source & honest note |
|---|
Where this model could be wrong — the honest list
- The deflation may simply not happen. Baumol's cost disease, tariffs, supply shocks, and institutional pricing power are real forces with long track records. 2025 saw solar system costs rise on policy alone. The pessimistic scenario is not decoration — it is a live possibility.
- The timeline is contested by serious people. Kurzweil says 2045. Acemoglu's NBER work implies AI's measured economic effect this decade is under one percent — total. Both are cited in the anchor-dial notes; the dial exists because we don't know who's right.
- Cheap capability is not cheap access. A collapsing production cost can land as consumer surplus or as producer margin. Nothing guarantees the curve reaches your bill.
- Garbage in, garbage out. Every output inherits your inputs. If the expense numbers are guesses, the runway is a guess wearing a chart.
- The simulator is deliberately simple. Annual steps, one real-return rate, no taxes, no Social Security or pensions, no sequence-of-returns risk, no market crashes, income assumed to cover costs while working. Real planning software models those; this tool models the one thing that software doesn't — differential cost curves — and keeps everything else minimal so you can see that one thing clearly.
- Floors and tiers are invented structure. Reasoned, but invented.
They're editable (floors) and shown (tier multipliers in
assumptions.js) so you can disagree precisely.
Lineage, credited
The question behind this tool — "what does retirement planning even mean if the Singularity is real?" — was asked publicly well over a decade ago, notably by RetirementSingularity.com, which built commentary around exponential tech, longevity, and money years before it was fashionable. This tool is our answer to that same question, built the ReThink way: interactive, every assumption on the table, and a range instead of a promise. The cost-curve data behind the deflating categories is charted with primary sources on our Convergence dashboard.
The lens — questions this tool opens, not answers it gives
The old planning frame had one move: estimate the pile you need, then hoard toward it. If the essentials of life keep costing what they cost, that frame is simply correct — and if that's your read of the future, set the caution dial to Traditional and use this page as a clean, honest calculator. Margin is a mercy. Nothing here argues against it, and the conservative reader is not this tool's target — they are its co-author. The pessimistic scenario exists because they might be right.
But if the curves are even partly real, the frame quietly gains options it never had, and the honest move is to name them as questions — because they are decisions only you can make, ideally with people who know you and, for the money parts, with a licensed professional:
- If the price of being alive and capable falls for decades, what was the extra margin for? What would you actually do with the years the old math said you couldn't afford?
- Money compounds — but so do health, skills, relationships, and community, and some of those compound better when funded early. What does your current plan implicitly assume about which ones matter?
- What's the cost of over-saving? The old frame counts only the risk of running out. Is there a risk of arriving at the far end with an untouched pile and an unlived decade — and how would you weigh it?
- If some help you could give — to family, to neighbors, to people getting crushed by the transition — lands tenfold harder now than in 2050, does that change anything for you? (A question about timing and meaning, not a suggestion about your money.)
- Which of your expenses are actually claims on human presence — the sticky kind — and which are claims on information and atoms, the kind that may fall? Does your picture of "enough" change when you sort them?
No tool can answer those, and you should distrust one that tries. What a tool can do is make the question visible — and refuse to pretend the old single-number answer was ever anything but a guess with good posture.
If this reframed anything
Go deeper, freely
This planner is one lens from a larger body of work on what the exponential age does to the assumptions we inherited — all of it free, none of it behind an email wall. The Convergence charts the seven cost curves this model leans on, from primary sources, with an honest counterpoints ledger. The ReThink essays work the same questions in prose — work, worth, scarcity, and what to do on a thousand-day clock. Read them if they serve you; build your own model if they don't. The assumptions file here is plain text on purpose.