The doctrine
Three numbers run through every reading, because they are the three numbers expensive decisions are actually made of and almost never computed.
After tax. Sticker prices are quoted in money you don't have. Every instrument works in net figures — your real income, the cash that actually leaves — because a purchase paid from a 40% bracket costs 1.67 gross dollars per net dollar, and pretending otherwise flatters every trade you make.
Opportunity cost. Money spent stops compounding. The true price of anything is what that capital becomes if left alone for the horizon — so every instrument future-values the money paths and shows the result under three market assumptions, never one. An assumption you can see is a tool; an assumption you can't is a trick.
Your hours. Past a certain income the scarce asset is time, and the research is blunt about it: higher earners report more time pressure, not less, and most never spend money to buy hours back. So every result is also priced in hours of your working life, at your effective hourly value.
The draft gauge
Every verdict in the house is read off the same figure: a ship's draft scale. The waterline shows how heavily the decision loads whatever is being measured — a year of income, a break-even, a net worth. The brass disc is a Plimsoll mark: the load line. Where the waterline sits against the disc is the reading; the words underneath only say it aloud.
The mark on the masthead is the same Plimsoll line. It exists because ships used to be loaded until they sank, and a painted circle on the hull ended the argument. Same question here, different cargo.
The conventions
Models need constants, and constants are choices. The house names its choices so you can disagree with them precisely. Every one is stated again on the page that uses it.
| Convention | Value | Why |
|---|---|---|
| Working year | 46 weeks | 52 minus realistic leave and holidays; sets every hourly figure. |
| Waking year | 5,840 h | 16 hours × 365 days; the denominator of a life. |
| Purchase safe-load line | 20% of a net year | Past it, a purchase competes with your savings rate, not your spending. |
| Purchase reconsider line | 45% · or ½ year in sticker | Where a purchase becomes a capital allocation. |
| Delegation bands | 85% / 115% | Under 85% of your cost, delegate; over 115%, keep it; between, a line-ball. |
| Oversight burden | 0 / 10% / 25% | Of task hours, at your rate — supervision is never free. |
| Sustained work-load line | 40% of waking hours | Past it, work consumes more of consciousness than the rest can repair. |
| Meeting line | 1 full-time person | 1,840 h collective a year — the slot employs a phantom. |
| Concentration line | 10% of net worth | Sized so a −50% single-name event costs at most 5% of the pile. |
| Housing payment line | 28% of net income | The classic front-end ratio, read against net rather than gross. |
| Year-one hire premium line | +50% over base | What an honest budget should expect a hire to cost beyond salary. |
| Ramp drag factor | 0.5 | During ramp, a seat is paid in full and produces about half. |
| Default market return | 6% nominal | A deliberately unheroic figure for diversified capital; always yours to change, always stressed ±2%. |
These are conventions, not laws of nature. Some houses draw the concentration line at 5%, some at 15%; the point of naming a line is that you can move it and see exactly what moves with it.
What the instruments are not
They compute; they do not advise. No instrument here knows your jurisdiction, your family, your risk appetite or your sleep. Where a page touches regulated ground — positions, mortgages, exits — it says so on its face, and the correct use of its output is as the sheet of numbers you bring to your adviser, not instead of one. Nothing on this site is investment, tax or legal advice.
How the machinery runs
Everything computes in your browser, from your inputs, at the moment you type. No market data is fetched, no figures are looked up, nothing is stored or transmitted. The formula behind every instrument is printed at the bottom of its page — under "Methodology — the formula, printed" — with the calculated parts and the assumed parts labelled as such. If you can't audit a number, you shouldn't act on it; here, you can audit all of them.
Corrections
Every page carries a rules version and a review date. When a convention changes or an error is found, the version increments and the change is noted here. The house would rather be corrected than trusted blindly.