The FERS COLA is one of the most misunderstood parts of federal retirement planning. FERS retirees under 62 get nothing. Those 62 and older get less than the full inflation adjustment. Here's how the rules work and what they mean for your long-term purchasing power.
A Cost of Living Adjustment (COLA) is an annual increase to your FERS pension designed to offset inflation. Without COLA, a fixed pension payment buys progressively less each year as prices rise. With COLA, the pension grows to partially compensate.
COLAs are set by statute and tied to the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W), which is published monthly by the Bureau of Labor Statistics. OPM compares the average CPI-W for the third quarter (July, August, September) of one year to the same period of the prior year. The percentage change is the basis for the following year's COLA.
COLA adjustments become effective December 1 of each year and are reflected in January payments. The first COLA you receive after retiring may be prorated based on how many months you have been an annuitant during the adjustment year. If you retired in April, your first COLA will be prorated at 8/12 (approximately 67%) of the full adjustment.
COLAs compound over time — each adjustment is applied to the already-adjusted annuity, not the original amount. This compounding makes COLA valuable over long retirements and makes the difference between FERS and CSRS COLA treatment increasingly significant the longer you live.
FERS retirees do not receive the full CPI-W increase as their COLA. Instead, the law applies a reduced formula that has been called the "diet COLA":
| CPI-W Increase | FERS COLA | Example |
|---|---|---|
| 2.0% or less | Full CPI-W increase | CPI 1.5% → FERS COLA 1.5% |
| Between 2% and 3% | 2.0% (flat) | CPI 2.7% → FERS COLA 2.0% |
| More than 3% | CPI-W minus 1 percentage point | CPI 6.0% → FERS COLA 5.0% |
In practice, this means FERS retirees typically receive less COLA than CSRS retirees in years when inflation runs moderate to high. Only in years where inflation is 2% or below do the two systems pay the same adjustment.
The diet COLA was a deliberate policy choice made when FERS was designed. The rationale was that FERS employees have Social Security (which also has COLA) and TSP (which can be invested for growth), providing inflation protection from other sources. CSRS employees, lacking Social Security and TSP contributions, were given a full COLA to compensate.
Who gets the diet COLA: FERS retirees age 62 and older. Special category employees (law enforcement, firefighters, ATCs) who retire under their special provisions also receive the diet COLA.
This is the least understood FERS COLA rule: if you are under age 62 on December 1 of the year a COLA is payable, you receive no COLA that year. Your pension amount stays flat — in nominal dollars — from the day you retire until you turn 62.
For an employee who retires under MRA+30 at age 57, this means 5 years without any inflation protection on their pension. If inflation averages 3% per year during that period, the real purchasing power of the pension declines by approximately 14% before COLA adjustments even begin.
Example: You retire at age 57 with an $36,000/year pension. After 5 years without COLA, in inflation-adjusted terms, your pension is worth the equivalent of roughly $31,000 in today's dollars (at 3% average inflation). When COLA begins at 62, it applies to the nominal $36,000 — but the lost purchasing power from the no-COLA years is not recovered.
This is an important input into retirement timing decisions. Employees who retire before 62 must plan for declining real income in their early retirement years, or rely on TSP withdrawals to bridge the gap. The FERS estimator in HighThree does not currently model COLA in real terms, so it's worth understanding this dynamic when interpreting the projected numbers.
Exceptions: FERS retirees who retired on disability receive COLA at any age. Survivors of FERS retirees who are over 62 may receive COLA depending on specific circumstances.
The COLA difference between FERS and CSRS is one of the most significant long-term financial advantages that CSRS retirees hold over FERS retirees — particularly in high-inflation environments.
| Feature | FERS | CSRS |
|---|---|---|
| COLA before age 62 | None | Full CPI-W |
| COLA at 62+ | Diet COLA (CPI − 1% if CPI > 3%) | Full CPI-W |
| COLA on supplement | None | N/A (no supplement) |
| Social Security COLA | Yes (separate from pension COLA) | Generally none (CSRS doesn't pay SS) |
FERS was designed with the assumption that Social Security's COLA would offset the reduced FERS COLA. Social Security adjustments use CPI-W and historically track closely to inflation. For FERS retirees who claim Social Security at 62 or FRA, the SS COLA does help restore purchasing power.
However, FERS retirees who retire at MRA (say 57) and don't claim Social Security until 62 or 67 have a 5–10 year window where only the frozen pension is available — no COLA, no Social Security, just a nominally flat annuity plus TSP.
The TSP is the key inflation hedge for FERS retirees in this window. Keeping a portion of TSP in equity funds (C, S, I) and drawing down conservatively provides a growth component that CSRS retirees do not have the equivalent of.
The COLA calculation process works as follows:
Social Security uses the same CPI-W measurement period and announces its COLA at the same time, so Social Security and FERS COLA announcements typically coincide each October.
In years where the CPI-W is flat or negative (deflation), there is no COLA. Annuities do not decrease. The minimum COLA is always 0% — you will never see your nominal pension reduced due to a negative CPI-W reading.
Here is a sample of recent FERS and CSRS COLA adjustments:
| Year (Effective) | CPI-W Change | FERS COLA | CSRS COLA | FERS Shortfall |
|---|---|---|---|---|
| 2016 | 0.0% | 0.0% | 0.0% | 0% |
| 2017 | 0.3% | 0.3% | 0.3% | 0% |
| 2018 | 2.0% | 2.0% | 2.0% | 0% |
| 2019 | 2.8% | 2.0% | 2.8% | −0.8% |
| 2020 | 1.6% | 1.6% | 1.6% | 0% |
| 2021 | 0.0% | 0.0% | 0.0% | 0% |
| 2022 | 5.9% | 4.9% | 5.9% | −1.0% |
| 2023 | 8.7% | 7.7% | 8.7% | −1.0% |
| 2024 | 3.2% | 2.2% | 3.2% | −1.0% |
| 2025 | 2.5% | 2.0% | 2.5% | −0.5% |
The years with zero or sub-2% inflation (2016, 2017, 2018, 2020, 2021) produced identical FERS and CSRS COLAs. The diet COLA shortfall only materialized in years with higher inflation. The 2022–2023 high-inflation period showed the diet COLA's real cost: FERS retirees received adjustments 1 percentage point below CPI each year, which permanently reduced their pension in real terms compared to CSRS.
Over a high-inflation decade, the cumulative shortfall between FERS and CSRS COLA can be 3–8 percentage points of purchasing power. This is a real but manageable cost — the FERS system compensates through TSP and Social Security — but it should be factored into long-term income planning.
The FERS Annuity Supplement — the payment that approximates Social Security for MRA+30 and age 60+20 retirees from retirement until age 62 — receives no cost of living adjustment. Its nominal value is fixed at the amount calculated when you retire.
If you retire at 57 with a supplement of $1,500/month ($18,000/year), that supplement will still be $1,500/month when it stops at 62 — regardless of how much inflation has occurred over those 5 years.
In real terms, at 3% annual inflation over 5 years, the $18,000 supplement is worth only about $15,500 in today's dollars by the time it ends. The supplement is still valuable — but understanding that it erodes in real terms helps set realistic expectations for early retirement income.
Social Security itself, which begins at 62 (or later if you choose to delay), does receive its own COLA adjustment tied to CPI-W. So once the supplement ends and Social Security begins, that component of your retirement income will have inflation protection.
For more details on how the supplement is calculated and when it stops, see the FERS Annuity Supplement guide.
COLA adjustments are applied to the current annuity amount each year — meaning they compound. Each year's higher annuity becomes the base for the next year's adjustment. Over a long retirement, this compounding is powerful.
Here's what a $36,000 annual pension looks like at age 87 under different COLA scenarios, starting at age 62:
| Scenario | Annual COLA | Value at Age 72 | Value at Age 82 | Value at Age 87 |
|---|---|---|---|---|
| No COLA | 0% | $36,000 | $36,000 | $36,000 |
| FERS (avg 2%) | 2% | $43,900 | $53,500 | $59,100 |
| CSRS (avg 3%) | 3% | $48,300 | $64,900 | $75,300 |
By age 87, the FERS pension at a 2% average COLA is nearly 64% higher in nominal terms than at retirement — $59,100 vs. $36,000. The CSRS pension at 3% average COLA is 109% higher. The difference between them by age 87 is over $16,000/year — compounded from a single percentage point difference in COLA rate over 25 years.
This also illustrates why the no-COLA period before 62 matters: FERS retirees who retire at 57 miss 5 years of compounding. When COLA begins at 62, it applies to the original pension amount — the 5 years of no-COLA represent a permanently lower starting base.
For FERS retirees, TSP withdrawals should be calibrated over time to supplement the pension's real purchasing power loss in the early retirement years before Social Security and COLA begin doing their work.
The estimator projects your pension, supplement, and TSP income for every departure year.