High-3 Salary Calculator
Calculate the average of your highest 36 consecutive months of basic pay — the number that drives your FERS pension.
Reviewed by Jonathan D., 20-year federal employee · Formulas verified against OPM.gov ·
What is the high-3 average salary?
Salary history
Tip: add separate periods for each promotion, step increase, or locality change.
How the high-3 calculation works
Your high-3 is the average of your highest 36 consecutive months of basic pay. OPM uses it as one of three components in your FERS pension formula: High-3 × years of service × 1% (or 1.1%).
OPM calculates the average using a 360-day year (30 days per month). Each salary rate you received during the 36-month window is weighted by the time you held it — so a promotion, locality change, or within-grade increase contributes proportionally to your final average.
Each rate is multiplied by a time factor based on how long you received it. For a full year at one rate the factor is 1.0; for 6 months it is 0.5. OPM's 360-day chart provides exact factors for any period.
How to calculate your high-3 for federal retirement — step by step
OPM calculates high-3 using a 360-day year (30 days per month). Every salary rate you held during the 36-month window is assigned a time factor based on how many OPM months you held it; rates are then multiplied by that factor, summed, and divided by 3. Here is the exact process:
Identify your beginning date
OPM counts backward exactly 36 months (3 years × 360 days = 1,080 days) from your retirement date — or from an earlier anniversary date if that window produces a higher average. The calendar date 36 months before September 1, 2027 is September 1, 2024, for example.
List every salary rate and its duration
For each rate you held, calculate the number of OPM months: count each day, then divide by 30. A period of January 1 through June 30 contains 180 days ÷ 30 = 6.000 months. OPM publishes a 360-day chart that converts any start/end date pair into an exact time factor.
Multiply each rate by its time factor
Divide the time factor by 12 to convert it from months to a fractional year factor. Example: 6 months ÷ 12 = 0.500. Then multiply your annual salary at that rate by the year factor. This gives the weighted salary contribution for that period.
Sum all weighted salaries, then divide by 3
Add the weighted salary amounts for every rate you held during the 36-month window. Divide the total by 3. The result is your high-3 average annual salary. OPM scans every possible 36-month window in your service history and selects the one that produces the highest average.
Apply the FERS multiplier
Multiply your high-3 by your years of creditable service (including fractions), then by 1.0% — or 1.1% if you retire at age 62 or older with at least 20 years of service. The result is your annual FERS annuity before any survivor reduction.
Where to find your salary data
You need your exact basic pay (with locality) for each period. Two official sources contain every figure you need:
What counts toward your high-3
Worked example: a promotion
An employee in Washington, DC retiring January 2027, promoted from GS-11 to GS-12 in their final three years.
| Period | Grade/step | Salary | Factor | Weighted |
|---|---|---|---|---|
| Jan 2024 – Dec 2024 | GS-11 Step 3 | $95,878 | 1.0 | $95,878 |
| Jan 2025 – Dec 2025 | GS-12 Step 1 | $101,401 | 1.0 | $101,401 |
| Jan 2026 – Dec 2026 | GS-12 Step 2 | $105,829 | 1.0 | $105,829 |
| Total weighted pay | 3.0 | $303,108 | ||
Worked example: moving to a lower locality
What happens when you move from Washington, DC (33.94%) to Rest of U.S. (17.06%) two years before retirement.
| Period | Locality | Salary | Factor | Weighted |
|---|---|---|---|---|
| Jan 2024 – Dec 2024 | DC (33.94%) | $122,299 | 1.0 | $122,299 |
| Jan 2025 – Dec 2025 | RUS (17.06%) | $107,009 | 1.0 | $107,009 |
| Jan 2026 – Dec 2026 | RUS (17.06%) | $107,919 | 1.0 | $107,919 |
| Total weighted pay | 3.0 | $338,788 | ||
High-3 for CSRS employees: the tiered formula
Civil Service Retirement System (CSRS) employees and CSRS Offset employees use the same high-3 average but a different annuity multiplier than FERS. CSRS uses a tiered percentage that rises with years of service, producing a substantially higher pension rate for long-career employees:
| Years of service | Multiplier per year | Applied to |
|---|---|---|
| First 5 years | 1.5% | Years 1–5 of high-3 |
| Next 5 years | 1.75% | Years 6–10 of high-3 |
| All years beyond 10 | 2.0% | Years 11+ of high-3 |
The maximum CSRS annuity is 80% of high-3, reached at approximately 41 years and 11 months of service. Unlike FERS, CSRS employees do not receive Social Security credits from federal service (though some may qualify through prior private-sector work) and there is no agency TSP matching contribution.
CSRS Offset employees use the same tiered formula, but their annuity is reduced at age 62 (or at retirement if later) by the Social Security benefit earned during CSRS Offset service — the two together typically equal or exceed a pure CSRS annuity.
Edge cases & special situations
Acting positions & temporary promotions
Extended LWOP (leave without pay)
Phased retirement
No "terminal leave" in federal service
High-3 calculator — frequently asked questions
The questions federal employees ask most about the high-3 average, what pay counts, and how the 36-month window works.
What is high-3 salary?
High-3 salary is the average of your highest 36 consecutive months of basic federal pay. It is used to calculate your FERS pension (High-3 × Years of Service × 1% or 1.1%).
Is my high-3 always my last 3 years?
Usually, but not always. Your high-3 is your highest 36 consecutive months, which could be earlier in your career if you had higher pay then (e.g., before a lateral move or locality change).
What counts toward high-3 salary?
Included: Base pay, locality pay, special rate supplements, LEO availability pay, and shift differentials (WG). Excluded: Bonuses, overtime, awards, allowances, night/Sunday differentials (GS), and COLA.
Does locality pay count toward my high-3?
Yes. Locality pay is included because retirement deductions are withheld from it. For example, the 2026 DC locality rate is 33.94%, so a GS-12 Step 1 base of $76,463 becomes $102,415 with locality - the full amount counts toward your high-3.
How do promotions affect my high-3?
If promoted during your highest 36 months, your high-3 includes both grades weighted by time. For example, 12 months at GS-11 ($95,878) plus 24 months at GS-12 ($103,000) produces a weighted average. Earlier promotions maximize your high-3.
Can I have gaps in my high-3 period?
The 36 months must be consecutive but not necessarily continuous. If you left federal service and returned with no intervening federal employment, you can combine both periods. However, you cannot cherry-pick your 36 highest individual months from different periods.
How do within-grade increases (WGIs) affect my high-3?
WGIs directly increase your high-3 since they raise your basic pay by approximately 3% per step. If a WGI is approaching and you are near retirement, waiting for that step increase will boost your high-3 and lifetime annuity.
What if I take a demotion near retirement?
Your pension is protected. OPM uses your HIGHEST consecutive 36 months, not necessarily your LAST 36 months. If you were a GS-13 from 2020-2024 then demoted to GS-12, your high-3 will use the GS-13 years since they produce a higher average.
How does part-time work affect my high-3?
OPM uses a "deemed" full-time salary rate for part-time work when calculating your high-3. This means your high-3 is based on what you would have earned full-time. However, your final annuity is then prorated based on actual hours worked over your career.
How can I maximize my high-3 salary?
Strategies: 1) Time promotions to occur early in your final 3 years, 2) Seek high-locality positions before retirement, 3) Wait for pending WGIs before retiring, 4) Request acting/temporary promotions, 5) Retire after January pay raises take effect.