How Social Security COLA is calculated
After 1983, SSA bases the COLA on the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W), series CWUR0000SA0, which is not seasonally adjusted.
- Use unadjusted CPI-W (not the CPI-U headline index).
- Average July, August, and September CPI-W for the current relevant year.
- Compare that average with the previous applicable third-quarter average.
- Take the positive percentage change, rounded to the nearest tenth.
- If there is no positive rounded change, there is no COLA (0.0%).
Official 2026 COLA regression fixture (SSA/BLS)
Previous Q3 CPI-W
308.729
- Next Q3 CPI-W
- 317.265
- Rounded COLA
- 2.8%
| Previous Q3 CPI-W | Next Q3 CPI-W | Rounded COLA |
|---|---|---|
| 308.729 | 317.265 | 2.8% |
Official 2026 worked example: (317.265 − 308.729) / 308.729 × 100 = 2.8% after rounding to one decimal.
A simple current-benefit × COLA estimate can differ from an actual check. SSA applies the COLA to the primary insurance amount (PIA) and uses truncation and other offset steps. Medicare premiums and other deductions can also change the net payment.
COLA Benefit computes the CPI-W percentage in a shared server/client module. The UI does not keep a second copy of the formula.
Open the live CPI-W tracker · COLA history
SSA remains the authority for the official COLA. A calculated CPI-W result is unconfirmed until SSA publishes it.