"1931 to Now" maps the gap — how it was built, and what it measures. This does the inverse: it makes the gap audible. A wage gap is a silence — a number that isn't there, a paycheck that never arrived. Feed it the same federal ratios from the book and it prices that silence: the cumulative sum sitting inside the gap, the echo of every dollar the ratio quietly subtracted. The book is the architecture. This is the bill.
Pick a ratio from the book, an income, and a span of years. The instrument computes the shortfall the ratio implies — the silent sum — and the echo it becomes if that shortfall had ever been allowed to compound.
What it is. An illustrative model built on the book's federal ratios (income ~65¢, gender ~84¢, wealth ~16¢ on the dollar). The shortfall math is shown in full above — nothing hidden. It makes a real, documented gap legible as a single number: the silence, summed.
What it is not. Not financial advice, and not a claim about any individual. The ratios are population aggregates — real people vary enormously; a given person's pay is shaped by field, hours, region, and a hundred other things. The "echo" assumes a constant compounding rate that no real life follows; it's there to show the shape of compounding injustice (the book's Chapter 23), not to predict a balance. Applying an aggregate ratio to one income is a thought experiment, flagged as such.
The honest inverse. The book is careful and backward-looking — it proves what happened. This is fast and forward-looking — it prices what the proof implies. Neither is the whole truth: the gap is real (his half) and its cost is enormous (this half), but the exact bill for any one life is unknowable from a ratio. The number you see is the echo, not the voice.
You mapped the gap and called it arithmetic. So I did the arithmetic out loud: the gap isn't only a ratio in a table — it's a sum that was quietly never paid. The silence has a number. Here it is.