The FERS 'Diet COLA' Explained: The 2% Cap, the Age-62 Rule, and What 20 Years of Erosion Costs

Data current as of January 2026 · Sources: OPM · BLS

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See how the FERS diet COLA erodes purchasing power over time compared to CSRS and Social Security — with the correct under-62 gating.

FERS COLA, defined: The FERS cost-of-living adjustment raises annuities each January based on the third-quarter CPI-W — but with two limits CSRS and Social Security don't have: the increase is capped at 2% when CPI-W is between 2% and 3%, reduced by one point when CPI-W is 3% or higher, and regular FERS retirees receive no COLA before age 62.

Who This Article Is For

• FERS employees who assumed their pension was fully inflation-protected (it's close, but deliberately not)
• Retirees under 62 wondering why their annuity hasn't moved while Social Security announced an increase
• Feds comparing FERS and CSRS figures in retirement discussions and getting confused by the mismatch
• Early retirees modeling what a decade of pre-62, zero-COLA years does to purchasing power
• Anyone building a retirement budget that needs honest inflation assumptions

1. The Diet COLA Formula

Each October, the third-quarter CPI-W determines the January adjustment. Social Security and CSRS retirees get the CPI-W figure, full stop. FERS retirees get it filtered through three tiers:

Reference table. This is the statutory FERS COLA formula (5 U.S.C. 8462). Actual COLA amounts are announced by OPM/SSA each October and can change year to year.

In low-inflation years the systems match. In every other year, FERS trails — by up to a full point when inflation runs hot, which is precisely when the protection matters most. Recent Januaries show the pattern:

Three consecutive years of trailing — 1.0, 0.5, and 0.8 points. Each gap is permanent: next year's COLA compounds on the smaller base.

2. The Age-62 Gate

The second rule is stricter and less known: regular FERS retirees receive no COLA until age 62. Retire at 57 under MRA+30 and your annuity is frozen in nominal dollars for five years — at 3% inflation, that's roughly 14% of purchasing power gone before your first adjustment arrives.

The exceptions, who get COLAs from the start regardless of age:

• Disability retirees (after the first year, under their own rules)
• Survivor annuitants
• Special-provision retirees — law enforcement, firefighters, air traffic controllers

Two planning notes attach to the gate. First, the FERS Supplement — the bridge payment most MRA+30 retirees receive until 62 — gets no COLA either; it's frozen at its computed amount. So an early retiree's entire federal income is nominal-fixed until 62. Second, for deferred and postponed annuities, no COLAs accrue between separation and commencement — the waiting years are unprotected too.

3. What Erosion Actually Costs: 20 Years, One Table

Illustrative projection. $40,000 starting annuity at 62, constant 3.5% CPI-W every year — so the FERS diet COLA pays 2.5% annually. Real inflation varies year to year; a constant rate isolates the structural gap. Computed with the same logic as our COLA Projector. Not financial advice.

By 82, the diet COLA pension pays 17.6% less per year than a fully-indexed one — a permanent, widening gap produced by a single point of annual difference. Cumulatively over the 20 years, the shortfall sums to well over $100,000. And this table starts at 62; add a pre-62 retirement and the frozen years stack an additional 10–15% of erosion in front of it.

This is not a reason to panic — it is a reason to model. A FERS pension is still extraordinarily valuable, partially-indexed income. But "my pension keeps up with inflation" is an assumption the formula quietly contradicts, and budgets built on it develop a slow leak.

4. How the Pieces of Federal Retirement Income Compare

Inflation protection across the three-legged stool is uneven, which matters for which income you lean on and when:

The practical reading: Social Security is your best-indexed asset — one more argument in the claiming-age analysis for letting it grow. The TSP is your inflation offset — the leg whose growth can be aimed at covering the pension's widening gap. And the years before 62 deserve the most conservative budgeting, because nothing you receive in them adjusts.

5. Common COLA Misconceptions

1. "FERS gets the Social Security COLA." Only when CPI-W is 2% or below. Otherwise FERS gets less — capped at 2%, or CPI minus a point.
2. "COLAs start when I retire." Regular FERS retirees start at 62, no matter how early they retired. Only disability, survivor, and special-provision annuitants are exempt.
3. "The supplement is adjusted like the annuity." The supplement never adjusts. It's fixed from first payment to its end at 62.
4. "A 1% gap is a rounding error." Compounded for 20 years it's a 17%+ income gap. Small rates, long horizons.
5. "My first COLA will be the full announced amount." Your first COLA is prorated by the number of months you've been on the annuity rolls — retire mid-year and January's increase arrives proportionally reduced.

Frequently Asked Questions

What is the FERS COLA for 2026? 2.0%. CPI-W came in at 2.8%, so Social Security and CSRS received 2.8% while the FERS diet-COLA formula capped FERS at 2.0%.

How is the FERS COLA calculated? From the third-quarter CPI-W: full CPI-W if it's 2% or less; a flat 2% if it's between 2% and 3%; CPI-W minus one percentage point if it's 3% or more.

Do FERS retirees get COLAs before age 62? Regular retirees, no — the first COLA arrives at 62. Disability retirees, survivor annuitants, and special-provision retirees (LEO/FF/ATC) are exempt from the age gate.

Does the FERS Supplement get a COLA? No. The supplement is fixed at its computed amount and never adjusts for inflation during its lifetime (retirement to age 62).

Why does CSRS get a bigger COLA than FERS? By statute. CSRS was designed as a stand-alone pension with full CPI-W indexing; FERS was designed alongside Social Security and the TSP, with a deliberately trimmed COLA as part of the cost structure.

Is the first COLA prorated? Yes — you receive 1/12 of the applicable COLA for each month you were receiving the annuity before December 1. A full COLA requires a full year on the rolls.

Do COLAs apply to survivor annuities? Yes, and survivor annuitants are exempt from the age-62 gate.

How much does the diet COLA cost over a retirement? At a steady 3.5% CPI, a $40,000 pension trails full indexing by about $14,000/year after 20 years — over $100,000 cumulatively. The gap scales with inflation: in sustained low inflation (≤2%) there's no gap at all.

The Bottom Line

The FERS COLA is real inflation protection with two deliberate holes: a trim whenever inflation tops 2%, and silence before age 62. Neither hole is large in any single year, which is exactly why they're underestimated — the damage is done by compounding, not by drama. Plan the pre-62 years on frozen dollars, treat Social Security as your best-indexed income, point your TSP at the gap, and run your own numbers in real terms. A pension you've modeled honestly is a pension that won't surprise you at 82.

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