How the math works
We take your income today, shrink it to that year's dollars using inflation (CPI-U), and run it through that year's federal brackets. Salary mode first subtracts the 2026 standard deduction ($16,100 single, $32,200 married).
Included: surtaxes, wartime caps, the 1988 to 1990 "bubble," the 1940 defense tax, the 1968 to 1970 surcharges and the postwar rate cuts. Left out: deductions, credits, the 1943 Victory Tax, AMT, capital gains, payroll and state taxes. Before 1948 couples filed separately, so both filing choices use the same brackets. Average pay is the Social Security wage index, which starts in 1951. Just for fun, not tax advice.
Sources: Tax Foundation, IRS 2026 brackets, CPI, SSA wage index, IRS prior-year forms.