Incolator
Incolator/Spending & savings/Idle Cash, Priced

Spending & savings · 2 min

Idle Cash, Priced

Cash feels like zero risk because the number never goes down. The price does the moving instead. This instrument prices the drain — deposit rate against inflation, compounded over your horizon — and separates the cash that's doing a job (the liquidity floor) from the cash that's just quietly shrinking.

Currency-agnostic · symbol only Rules version 1.0 Reviewed July 2026

Your details

Σ

Current accounts, savings, the float that never moves.

% / yr
% / yr

Your honest expectation, not the target. The scenarios test ±1.5 points regardless.

years
Σ/ mo

Sets the liquidity floor — the cash that's employed, not idle.

Everything is calculated in your browser as you type. Nothing you enter is sent or stored, and no account is needed.

Your result

Paying rent to inflation.

$46,478

purchasing power the pile loses over 5 years, at these rates

The quiet ledger

The pile, nominal, at the horizon
What it buys then, in today's money
Purchasing power lost
The drain, per year
Liquidity floor (6 months) — the cash with a job

Three inflations, same pile

If prices run atReal value at horizonLost

What moves this result

Worth checking

The floor exists for a reason. Cash that covers six months of life is insurance, and insurance is allowed to cost something — the drain only becomes waste above the floor.

Chasing yield to escape the drain has its own failure modes: lock-ups when you need the money, and risk that arrives exactly when everything else falls too.

Real rates flip sign. When deposits pay more than inflation, idle cash quietly earns — this page is worth re-reading whenever the central bank moves.

Common questions

How much does inflation cost me on cash savings?
The gap between your deposit rate and inflation, compounded. At 1.5% earned against 3.5% inflation, $500,000 loses about $46,700 of purchasing power over five years — roughly $9,300 a year — while the account statement shows the number going up.
How much cash should I keep liquid?
The common convention is three to six months of spending as an emergency floor; this instrument uses six. Cash up to the floor is doing a job — insurance against life — and only the excess above it is fairly described as idle.
Is holding cash ever the right position?
Yes: when real rates are positive, when a known expense is near, when dry powder has a named purpose, or when the alternative would be sold in a panic. The instrument doesn't say cash is wrong — it prices what the comfort costs, so the choice is made with open eyes.
How this is calculated

Everything below is calculated from your inputs. Inflation is an assumption you control; the scenarios stress it ±1.5 points regardless.

real_factor = ((1 + deposit) / (1 + inflation)) ^ n real_value = cash × real_factor lost = cash − real_value floor = 6 × monthly_spending

The gauge reads purchasing power lost over the horizon as a share of the pile, the line at the house 5% — the level at which the drain stops being a rounding error and starts being a position. The liquidity floor of six months' spending is a convention: cash below it is employed, not idle.

Limitations. One inflation figure stands in for your personal basket, which may run hotter. What the excess cash should do instead is a conversation for you and an adviser — this page only prices the cost of not having it.