The argument — read this before you touch the numbers
Five rules. Four you can run yourself.
Most of what the financial industry sells is optimization at the margin — fund selection, expense ratios, the next rate decision, whether now is a good time to be in the market. That conversation is loud because it is easy to have and easy to sell.
Here is the part nobody leads with. Investment return is a multiplier on a number you control. Most people spend their attention on the multiplier and almost none on the number.
Same year, same person. One of those numbers is eighteen times bigger than the other — and it is the one that does not depend on being right about the market.
So the order of operations is not negotiable. Cash flow funds savings. Savings rise faster than income. Wealth reaches perpetuity, the point where the portfolio earns more than you spend. If the first number is negative, the last is a fantasy, and no amount of portfolio construction fixes it.
The industry sells complexity where the math is simple, and goes quiet where the decisions are actually hard.
None of which means returns are irrelevant. They matter enormously — later, as a multiplier, not as a substitute. Rule 4 is where that stops being arithmetic and starts being judgment, and it is deliberately the one rule this worksheet will not answer for you.
This is our actual method. Not a lead-magnet version of it — the real thing, the same five rules we work through with clients. It is free, no email is required, and nothing you enter is saved or sent to us. We give it away because a method you can check is worth more than one you have to trust.
The five rules — work them in order
Rule 2 sets the rate. Rule 3 decides what happens to it when your income moves. Most people let raises land in their lifestyle by default — the savings rate quietly falls every year they get paid more.
Same person, same raises, same market. The only difference is what happens in the month a raise arrives.
Enter your numbers to compare the two paths.
Every number you have entered rests on one assumption.
Rules 1, 2, 3, and 5 are arithmetic. Give them inputs and they produce an answer, and the answer is correct or it isn't. That is why they belong in a worksheet, and why you can run them without help from anyone.
Rule 4 is not like that. There is no return figure that is simply right. The number you typed into "expected return" is doing more work than every other input on this page combined — and it is the only one you cannot fix by budgeting.
A portfolio built for one environment works beautifully until the environment changes. Inflation, recession, rate shocks, and a flat decade are not tail risks; they are the ordinary weather of a thirty-year plan. The point of building for several environments at once is not to maximize the return figure. It is to narrow the range of things that can happen to it.
So instead of an allocation, here is the honest exercise: what does your plan survive? Same savings behavior from Rule 3, four different environments.
Years to perpetuity — how long until your portfolio is large enough to cover your yearly spending from its own growth, without shrinking.
If the difference between these four columns is larger than the difference every budgeting decision you will ever make — and it usually is — then the assumption deserves more attention than the budget.
That is not an argument for chasing returns. It is the opposite. It is an argument for building a portfolio whose outcome does not depend on which column you land in — and for being honest that the choice involves judgment, tradeoffs, and someone accountable for them.
This worksheet deliberately produces no recommended allocation. Any tool that hands you a portfolio from four questions is selling something.
Three things this screen cannot see. If the income starts in a later year, the portfolio carries everything until it does. If it does not rise with inflation — most private pensions don't — it buys roughly a third less after twenty years. And if it would fall when a spouse dies, which Social Security does, the portfolio's job gets larger at the worst possible moment while spending barely moves. In all three cases the real requirement is higher than the figure shown. Those are conversations, not checkboxes.
Closing the gap — what Rule 3 buys you
Complete Rules 1 through 3 to see how long each path takes to reach your perpetuity number.
Your progress through the five rules
Your numbers — summary
Figures reflect the assumptions you entered. Projections are hypothetical illustrations, not predictions. See disclosures below.