FERS High-3 Salary: How It's Calculated and How to Maximize It

Your FERS annuity formula is: years of service × multiplier × high-3 average salary. Of those three inputs, the multiplier is fixed and years of service grows on its own. The high-3 is where planning decisions — promotion timing, locality moves, part-time choices, retirement-date selection — make a permanent difference.

What is the high-3 average salary?

OPM defines your high-3 as the highest average basic pay you earned during any 3 consecutive years of federal service.¹ In practice, for most federal employees, the last 3 years of their career are their peak earning years — so the high-3 is almost always drawn from the final 36 months before retirement.

The important word is "consecutive." You cannot cherry-pick your three best individual years. If you took a salary reduction mid-career (a move from SES to GS, a downgrade during a RIF, or extended leave without pay), your high-3 must cover 36 uninterrupted months. OPM will test every possible 36-month window in your service history and use the one with the highest average.

What counts as basic pay — and what doesn't

Not all federal pay counts toward the high-3. OPM uses "basic pay" — the salary for which retirement deductions are withheld under 5 U.S.C. § 8331(3) and § 8401(4).²

Locality pay is critical. Since OPM incorporated locality pay into the definition of "basic pay" for retirement purposes, the significant locality adjustments in metropolitan areas flow directly into your high-3. A GS-14 in the Washington-Baltimore area (33.94% locality in 2026) earns roughly $187,000/year — all of it creditable — versus the same GS-14 in a Rest of U.S. locality at ~16.82%, earning about $163,000.³ That $24,000 difference compounds across your entire high-3 window.

How OPM calculates the weighted average

OPM does not simply average your W-2 salaries for three calendar years. Instead, it uses a 360-day year convention (treating each month as 30 days) and weights each pay rate by the number of days you earned it within the 36-month window.²

If you received a promotion or step increase partway through your high-3 period, only the portion of that window at the new rate counts at the new rate. A promotion in month 13 of a 36-month window means 24 months (two-thirds of the period) at the new, higher rate — not a full three years. This is why the earlier a raise lands within your high-3 window, the larger the impact on your annuity.

Five strategies to maximize your high-3

1. Align your retirement date with step increase timing

Within-grade increases (WGIs) for GS employees happen on a fixed schedule: every 1–2 years depending on grade and step. Check your current step and when your next WGI is due using your SF-50. If your next step increase lands within 2–3 months of your planned retirement date, waiting can capture that rate for your full high-3 window.

The math: at GS-14 in Washington DC, a single step increase adds approximately $4,700–$5,200/year to your salary. If it falls fully within your high-3 window, that's $47–$52/year more pension at the standard 1% multiplier — for the rest of your life.

2. Do not go part-time in the final 3 years

Part-time federal service is paid at a prorated hourly rate. A GS-14 at 80% full-time earns 80% of the GS-14 salary — and that lower amount becomes part of your high-3. If you work part-time for even one year of your high-3 window, the average pulls down.

Example: if you earn $175,000 full-time for 2 years and $140,000 at 80% for 1 year, your high-3 is ($175,000 + $175,000 + $140,000) ÷ 3 = $163,333 — not $175,000. The annuity impact at 30 years of service: 30 × 1% × $11,667 less = $3,500/year less pension for life. A part-time arrangement that saves stress for one year costs over $70,000 in cumulative pension over a 20-year retirement.

If you need to reduce your workload before retirement, explore other options: leave without pay for specific periods (which pauses service credit accrual but doesn't dilute your pay rate), maxing annual leave, or requesting a phased schedule that still qualifies as full-time.

3. Time promotions to land before your high-3 window opens

A promotion to the next GS grade — say GS-14 to GS-15 — can increase basic pay by $20,000–$30,000 depending on locality. If you're promoted in the final 3 years, only the post-promotion period is captured at the new rate. If you're promoted at year 30 of a 33-year career, your entire final 36-month window is at the GS-15 salary.

This is often more of an observation than a controllable variable — promotions depend on vacancies and agency decisions. But if a promotion opportunity comes with 3–5 years to go, it's worth more than the same promotion 10 years out, because it elevates the base for your entire high-3.

4. Understand how locality changes affect your high-3

Permanently transferring to a higher-locality duty station raises your basic pay even without a grade or step change. A transfer from Rest of U.S. (~16.82%) to Washington DC (33.94%) at GS-14 step 10 raises your salary from approximately $163,100 to $187,000 — a $23,900 difference that flows entirely into your high-3 if it occurs within or before the final 36-month window.

Conversely, if a position requires moving from a high-locality area to a lower one, and that move occurs within 3 years of retirement, it reduces your high-3. This is worth factoring into any lateral-move decision late in your career.

5. Know the 1.1% multiplier threshold — it's not just about years

The standard FERS multiplier is 1% per year. If you retire at age 62 or older with 20 or more years of creditable service, the multiplier increases to 1.1%.¹ This 10% lift applies to your entire annuity — it's not just the years after 62.

The 1.1% multiplier interacts with high-3: by waiting until 62, you not only unlock the higher multiplier but typically accumulate additional salary increases that raise your high-3. The combination can be substantial.

Common high-3 mistakes

• Retiring mid-year before a step increase. If your WGI is due in November and you retire in August, you leave 3 months of higher pay — and years of compounded pension — on the table. Check your SF-50 before setting a retirement date.
• Confusing gross pay with basic pay. Federal employees in high-overtime roles sometimes assume their total compensation drives the high-3. It doesn't. Overtime, awards, and shift differentials are excluded. Your W-2 will be higher than your basic pay rate — and the difference doesn't count.
• Assuming the high-3 is always the final 3 years. OPM checks every consecutive 36-month window. If you had a higher salary period earlier — perhaps you were SES and stepped down, or had a temporary promotion — that earlier window may yield a higher high-3 than the final 3 years. Know your full pay history.
• Ignoring the interaction with the FERS supplement. The FERS supplement is based on Social Security earnings, not your FERS high-3. These are two separate calculations. High-3 planning maximizes your basic annuity; Social Security timing affects the supplement. Both deserve separate optimization.

How a federal-benefits specialist can help

Maximizing the high-3 requires a multi-variable analysis: step increase schedule, locality options, potential promotions, part-time trade-offs, and the 1.1% multiplier decision. Each variable interacts with the others. A generalist financial advisor may not model these interactions correctly — particularly the 360-day weighting convention OPM uses, which most commercial software does not replicate accurately.

Fee-only advisors who specialize in federal benefits work through this calculation using your actual SF-50 history, your current step and expected WGIs, and your retirement date options — and tell you in dollars what each scenario means for lifetime annuity income.

Sources

1. OPM — FERS Computation: high-3 average salary definition, 1% and 1.1% multiplier rules, age 62 with 20+ years threshold. Verified 2026.
2. OPM — Rates of Pay to Use in Processing Pay Actions: definition of basic pay for retirement computation purposes, including locality pay and excluding overtime, awards, and allowances.
3. OPM — 2026 Salary Table DCB (Washington-Baltimore-Arlington): GS-14 Step 10 base $139,684; locality rate 33.94%; locality-adjusted salary $186,924. Effective January 2026.
4. FEDweek — FERS Annuity Calculator and Explanation: high-3 weighting methodology, part-time service impact, and multiplier interaction. Cross-reference for computation examples.

FERS computation rules, basic pay definitions, and 2026 GS salary tables verified against OPM publications. Current as of May 2026.