August · The Decision Calendar

The Window

Alex Alston

What the next dollar of conversion actually costs — not what the bracket table says. This computes the real marginal rate including the Social Security effect, capital gains displacement, and the senior deduction phase-out.

01Your year, before any conversion From July's projection
02Size the conversion
What each additional dollar costs, as the conversion grows
True marginal cost What the bracket table says Your current conversion
03Which ceiling binds first
04Convert, or harvest gains? They compete for the same space
05What this tells you

Carry forward to November

The true marginal rate is measured by computing your full federal tax at your income and again a step higher — which captures the Social Security effect, capital gains displacement, and the senior deduction phase-out without assuming any of them. Federal only; state tax is not included. Conversions cannot be undone. Bring this to the August call.