Methodology
Life Days Left combines a fixed income-linked age-at-death baseline, a birth-year cohort adjustment, and exact calendar days lived. Every displayed value follows the same rule.
Inputs
Chetty et al.’s national, race- and ethnicity-adjusted expected age at death at age 40 for the 75th household-income percentile. The model takes an equal arithmetic mean of the published male and female values.
85.0786285 years
SSA 2026 Trustees Report Table V.A5 Intermediate cohort life expectancy at birth. Male and female values are averaged for each birth year, then expressed relative to 1967.
1967 reference: 78.3 years
The model converts the estimated age to days using the mean tropical year and subtracts exact UTC calendar days between a birth date and the daily UTC−04:00 as-of date.
365.2425 days per year
Calculation
85.0786285 + [SSA cohort e0(birth year) − 78.3]estimated age at death × 365.2425round(modeled lifetime days − calendar days lived)round(days left ÷ modeled lifetime days × 100)For a 1967 birth year, the cohort-shift bracket is zero, so the estimated age equals the Chetty baseline before elapsed calendar days are subtracted. This is a reference case, not a prediction for every person born in 1967.
Chart construction
The chart uses Boomers (1946–1964), Gen X (1965–1980), Millennials (1981–1996), Gen Z (1997–2012), and Alpha (2013 onward). These match the U.S. Census Bureau’s 2025 birth-cohort bands; Pew provides additional documentation for the Millennial and Gen Z boundary.
Each gold range connects the modeled percentage for the oldest and youngest boundary date. Alpha’s youngest boundary is the as-of date because the cohort is open. The white point uses one stable representative birth date near the center of each band. It is a chart reference, not a population-weighted median.
Read the deeper explanation in life expectancy by generation.
Scope
Illustrative population estimate only. It is not personal, medical, actuarial, insurance, or financial advice.
Primary sources