The range calculator
The bracket is not the answer.
The number a client remembers is their bracket. But the number that decides whether a Roth conversion, a gain harvest, or a part-time job makes sense is the rate their next dollar actually pays. The two are often nowhere near each other. Here is that gap for the demo client: 61 real runs of the entire federal return, one every thousand dollars of added wages, with nothing guessed in between.
Effective marginal rate on the next dollar of wages
Demo client, married filing jointly, tax year 2024
- Effective marginal rate
- Total burden in dollars
- Filed position
Their ordinary bracket is 12 percent. The next dollar of wages is taxed at 27. Here is why: as that dollar goes in, it drags a dollar of their dividends and long-term gain out of the zero percent rate. An ordinary 12 and a preferential 15 land on the same dollar.
That holds for exactly 22,000 dollars, which is the room left in their zero percent band, and then the rate falls to 22. A client earning more can pay a lower rate on the next dollar than the same client earning less. No bracket table will ever tell you that, and it is the difference between advice and arithmetic.
Every point is a real run of the whole return at that income, not a curve fitted between two of them. A computed projection under the stated assumptions, not a certainty. The derivation behind the filed position is on the engine page.