The cost of a decision isn't what it takes out of your account — it's the best thing you gave up to make it. This puts every competing use of the same lump sum side by side over the same horizon, so you can see what each one is really costing.
Money that sits undeployed for a few years while you decide doesn't stay still — it falls behind.
A way of seeing all your options at once, rather than judging each one in isolation.
The cost of a decision isn't what leaves your account — it's the best thing you gave up to make it. Put $120,000 into the mortgage and the cost isn't $120,000; it's whatever that money would have become somewhere else.
This matters because we tend to evaluate options one at a time. "Should I pay off the mortgage?" feels like a yes-or-no question, and answering it that way hides the four other things the money could have done. Lining them all up on the same chart, over the same period, makes the comparison honest.
Graham has $120,000 from a matured investment and a 15-year horizon. His options: pay down a 4.2% mortgage, invest at 7.5% taxed at 20%, leave it in cash at 3.2%, give it to his daughter, or spend it on the travel he and his wife have been putting off.
Over 15 years the money becomes roughly $222,000 against the mortgage, $272,000 invested, $174,000 in cash, and nothing if spent.
Leaving it in cash — the option that feels like "not deciding" — costs him about $98,000 against investing. That's the finding that surprises people. Indecision isn't neutral; it's a decision to hold cash, and it's priced accordingly.
Solid lines are near-certain outcomes. Dashed lines depend on returns nobody can promise. That distinction matters more than the heights of the lines — a dashed line sitting above a solid one is an expectation, not a result.
Note that "spend it now" is valued at zero. That's a limitation of arithmetic, not a judgement. A calculator has no way to price two weeks with your grandchildren, so it prices it at nothing — which is precisely why it needs to be on the list rather than quietly left off it.
Giving it away often earns the highest return of anything on the list, just not to you. Money that clears a child's 7% debt, or starts a house deposit a decade earlier, compounds in ways this table can't capture. The helping the kids calculator checks whether you can afford it.
Spending it is not the irrational choice. Health, energy and the people you'd travel with are all depreciating assets, and they depreciate faster than money compounds. The active years genuinely do end — the spending ramp calculator shows the shape of that.
The point of putting a number on each option isn't to make you choose the largest one. It's to make sure whichever you choose is a decision rather than a drift.
General information only — not financial advice. Comparing a guaranteed return against an expected one on the same axis makes them look more alike than they are; the mortgage and cash figures are close to certain, the investment figure is an average across outcomes that vary enormously. The "spend it now" option is deliberately valued at zero financially, which is not the same as saying it's worth nothing — a calculator simply has no way to price it, and that limitation is the point rather than a flaw.