The formula
Section 230(b) of the Social Security Act sets a fixed reference point: the 1994 wage base of $60,600 and the 1992 average wage index of 22,935.42. Each year, the base is recalculated by indexing that reference amount to the average wage index for the second year before the base year.
The result is rounded to the nearest $300. No discretionary adjustment is permitted in either direction.
The 2027 arithmetic
For 2027, the applicable index — average wages for 2025 — is 72,800.33. Divide by the 1992 figure and multiply by the 1994 base:
- 72,800.33 ÷ 22,935.42 = 3.1742
- 3.1742 × $60,600 = $192,354
- Rounded to the nearest $300 = $192,300
| Year | Wage base | Maximum employee tax | Maximum self-employed tax |
|---|---|---|---|
| 2026 | $184,500 | $11,439.00 | $22,878.00 |
| 2027 | $192,300 | $11,922.60 | $23,845.20 |
| Change | +$7,800 | +$483.60 | +$967.20 |
The 4.2% increase in the base is smaller than the 4.3% implied by the index alone because of rounding, and it is unrelated to the 3.6% COLA, which is measured against prices.
Why wages, not prices
The base exists to keep the share of covered earnings subject to Social Security tax roughly stable over time. If the ceiling were fixed in nominal dollars, wage growth would steadily push more earnings above it and the tax would apply to a shrinking share of payroll.
Indexing to average wages keeps the ceiling in the same position relative to the wage distribution. Indexing to prices instead would let the ceiling drift downward in real wage terms, because wages generally grow faster than prices over long periods.
This is also why the base and the COLA diverge. Benefits are indexed to prices after eligibility; the tax ceiling is indexed to wages throughout. In 2027 the two moved 3.6% and 4.2% respectively.
Who actually pays more
Only workers earning above $184,500 see any change in Social Security withholding. For everyone below the 2026 ceiling, the rate is unchanged at 6.2% and applies to every dollar either way; a higher base changes nothing on the pay stub.
The base caps two things at once: the tax and the earnings counted in the benefit formula. A high earner therefore receives a return on the additional $7,800 only through a marginally larger primary insurance amount, computed at the first bend point rate rather than dollar for dollar.
For a worker above both ceilings, the additional tax is $483.60 for the year as an employee, matched by the employer. A self-employed person at the maximum pays $967.20 more. The Medicare line is untouched — 1.45% with no ceiling, plus the 0.9% surtax above $200,000 single or $250,000 joint, neither of which is indexed.