Why your real earnings history beats a single-salary estimate
Social Security is designed around your actual career, not your current salary. The SSA calculates your benefit from your highest 35 years of earnings — averaged and adjusted for wage growth over time. A single-salary approximation (like the one used elsewhere on this site for the free instant estimate) assumes something close to a flat earnings trajectory. If you took a private-sector pay cut before joining federal service, worked part-time for several years, or had an unusually high-earning stretch, your real 35-year record tells a different story than one number can.
What this tool simplifies away
The SSA's official Average Indexed Monthly Earnings (AIME) calculation indexes every year of your earnings to account for national wage growth between that year and the year you turn 60 — a dollar earned in 1995 is worth more in the calculation than its face value, because average wages have grown since then. That indexing requires the SSA's National Average Wage Index for every year back to your first year of covered earnings. This tool does not apply that adjustment — it averages your top 35 years as entered, in nominal dollars. For most people this understates the true PIA, since indexing generally helps older, lower-earning years the most.
What this tool does get exactly right: the current bend-point PIA formula, your full retirement age by birth year, and the statutory early-claiming reduction and delayed-retirement credit percentages — all stable, published SSA rules rather than historical data tables.
The most accurate number available
For your official PIA, the SSA's own my Social Securitystatement already shows a personalized estimate that includes proper wage indexing — that number is more accurate than anything any third-party tool, including this one, can produce without SSA's internal data. This tool is most useful for modeling how a change — retiring earlier, working a few more years, a raise — shifts your top-35 average, and for comparing claiming ages once you have a baseline PIA from either source.