Based on the May 2026 CPI-W reading of 328.829, the 2027 COLA is currently tracking at about 3.6% for CSRS and 2.6% for FERS. This is a projection, not the final number — only July, August, and September 2026 data will decide it. The official figure is announced in mid-October 2026 and takes effect in January 2027 payments.
If you’re a retired postal worker — or close enough to retirement that you’re running the numbers — the annual cost-of-living adjustment is one of the most important figures in your financial year. It’s the only built-in protection your pension has against inflation. Here’s exactly where the 2027 COLA stands, how the calculation works, and why CSRS and FERS retirees don’t get the same number.
The Current Projection
The 2027 COLA is calculated by comparing the average CPI-W (Consumer Price Index for Urban Wage Earners and Clerical Workers) for the third quarter of 2026 against the same quarter in 2025. The Q3 2025 baseline was 317.265.
The most recent data point, May 2026, came in at a CPI-W of 328.829 — about 3.64% above that baseline, which rounds to a running estimate of 3.6%. Inflation has been climbing through the spring: CPI-W rose 4.4% over the 12 months ending in May 2026, the highest reading since 2023, driven largely by energy prices. That upward trend is why 2027 projections have moved from “probably under 3%” earlier in the year toward the 3.5–4% range now.
But here’s the critical caveat: May data doesn’t count. Only the July, August, and September 2026 CPI-W readings are used in the official calculation. The May number tells you the trend, not the outcome. If energy prices ease over the summer, the final COLA could land lower. If they stay elevated, it could hold near these levels or climb.
Why CSRS and FERS Get Different Numbers
This is the part that surprises a lot of retirees, especially those newly under FERS. CSRS retirees and Social Security recipients receive the full CPI-W increase. FERS retirees often receive less — a provision critics call the “diet COLA.”
Here’s the FERS rule:
| If CPI-W rises by… | CSRS & Social Security get | FERS gets |
|---|---|---|
| 2% or less | The full amount | The full amount |
| Between 2% and 3% | The full amount | Capped at 2% |
| 3% or more | The full amount | Full amount minus 1 point |
So at the current 3.6% projection, CSRS retirees would see 3.6%, while FERS retirees would see 2.6% (3.6% minus one percentage point). That one-point gap may sound small, but it compounds — next year’s COLA is calculated off the lower base, so the gap widens over time.
What It Means in Dollars
To make the gap concrete, here’s roughly what the current projection would mean on a $45,000 annual annuity:
| System | COLA | Annual increase |
|---|---|---|
| CSRS | 3.6% | about +$1,620/year |
| FERS | 2.6% | about +$1,170/year |
That’s a difference of roughly $450 per year at this benefit level — for the same inflation, in the same year, simply because of which retirement system you’re under. Adjust the numbers for your own annuity and the gap scales accordingly.
Want to see how a COLA affects your specific pension? Run your FERS or CSRS estimate with our free retirement calculator.
Open the Retirement Calculator →The Timeline From Here
Here’s the schedule that determines your 2027 increase:
- July 14, 2026 — June CPI-W released (still pre-window; trend only)
- Mid-August 2026 — July CPI-W released (first month that counts)
- Mid-September 2026 — August CPI-W released (second counting month)
- Mid-October 2026 — September CPI-W released, and the official 2027 COLA is announced
- January 2027 — the new COLA appears in your annuity payment
Only those three bold months — July, August, and September — go into the official math. Everything before is just the trend line.
A Note for Active Employees
If you’re still working, this retiree COLA is separate from your contract pay raises and the cost-of-living adjustments built into your union agreement. APWU and NALC COLAs are negotiated and calculated differently, on their own schedule. This page is about the annuity COLA that applies once you retire. For active-employee pay, see our APWU pay scale and contract COLA coverage.
We update this page each month as new CPI-W data is released, through the October announcement. Bookmark it if you want to track where the 2027 number is heading.
Sources: NALC Research & Economics, NARFE, Congressional Research Service, Bureau of Labor Statistics CPI-W data (May 2026).