How Enuf works

Most calculators grow your money at one average return and print the result. An average return is the one outcome that almost certainly will not happen, and it hides the thing that actually ruins retirements: the order in which good and bad years arrive.

So Enuf runs your plan 100 times. In each run, every single year gets its own randomly drawn return for every asset class you hold, centred on that class’s long-run average and scattered by its historical volatility. The draws are correlated, so a bad year for domestic equity is usually a bad year for international equity too — treating them as independent would understate how violent a portfolio really is and quietly inflate every success rate on the site.

Each of the 100 runs then gets a pass or fail on a strict test: the portfolio must never fail to cover a year of retirement spending, and every goal you set must be funded when it comes due. One missed goal fails the whole run. The percentage you see is simply how many of the 100 passed.

Alongside the 100 random paths, one deterministic path runs at the plain expected return with no volatility at all. That path answers the binary question — does the money last on the expected case — and the 100 answer the more useful one: how much of that answer survives contact with a market.

The random seed is fixed. Reloading your plan will not give you a different number; only changing your plan will.

90% is the bar the whole product is scored against. It is drawn on the confidence meter, and it decides whether each goal is reported as feasible — a goal funded in 89% of the paths is not called met.

It also means the headline can never flatter the number printed beside it. A plan whose expected path survives but which only 42% of markets carry is not a working plan, and it is not described as one:

Two rounding rules follow from the same discipline. A plan at 89.6% prints as 89.6%, never as a rounded 90% — nothing is allowed to round up across the bar it failed. And nothing ever prints 100%. A run in which every path survived is shown as “>99%”, because zero failures in 100 draws is a routine result rather than a perfect plan, and printing it as 100% would read as a guarantee of something nobody can guarantee.

Every figure Enuf shows you is in today’s money. A $44,000 withdrawal at 60 means what $44,000 means to you now. This is the single most important thing to know about reading the numbers, and it is why they may look smaller than other tools’ projections.

It works because the return assumptions are real, not nominal. The 7% US equity figure is 7% above inflation, drawn from roughly a century of index history adjusted for each country’s own inflation. Every year of every path, the engine computes the expected real return minus whatever fees you have entered, adds the random volatility term, and applies that. Inflation is never subtracted a second time, and spending is never inflated to compensate — both sides of the calculation already live in today’s money.

That 7% is applied as an average single year, not as a compound growth rate — it is the return of a typical year, not the rate that would turn a starting balance into an ending one. The difference matters because good and bad years do not cancel out when they compound: a portfolio that gains 20% and then loses 20% averages zero and is down 4%. So the single “Expected” line on every chart, which applies that average every year, ends up above the middle of the simulated futures drawn around it — over 30 years at 80% shares, roughly 64 of every 100 futures end below it. Read the line as a reference path and the band as the answer to “how might this actually go”.

Inflation is still in the model. It does exactly three jobs:

• It deflates your home’s value and your mortgage balance back to today’s money before they land in net worth, since both of those are genuinely nominal quantities.
• It converts a nominal growth rate you type on a goal — "education costs rise 10% a year" — into the real rate the engine needs.
• It keeps thresholds that are fixed in cash terms honest. US Medicare IRMAA bands and the Canadian OAS recovery threshold are deliberately held flat in today’s money rather than indexed upward, because indexing them while real income stays flat would let you drift out of every surcharge and always understate your costs.

What inflation never does is grow your portfolio or your spending.

Tax is where a retirement projection is usually at its vaguest — a single effective rate applied to everything. Enuf runs real progressive brackets on real account behaviours, per country, and shows you the bracket walk in the Your Money tab so you can see where each unit of income landed.

Every schedule below was entered by hand from the relevant published rates and is dated in the source. That is what we can claim. No tax authority has reviewed, certified or endorsed this model — which is why you will not find us saying otherwise anywhere on the site.

A default you cannot see is an assumption someone else made about your life. These are all of them. Every one is editable inside your plan, and the ones that matter most — returns, withdrawal rate, life expectancy — sit in the Edit panel on the dashboard.

This is the section we would most like to be shorter. It is here in full because a method you can only read the flattering half of is a brochure.