Your high-3 is the salary base for your lifetime FERS pension. A final promotion, locality move, or pay reduction can change the average that every future pension check is built on.
High-3 is the average of your highest three consecutive years of basic pay. Under FERS, that average is multiplied by your years of service and the pension multiplier to calculate your annual annuity. It is not always your final salary and not always a calendar-year average. The official concept is 36 consecutive months.
For most federal employees, high-3 is the final three years before retirement. Pay usually rises through annual raises, within-grade increases, promotions, and locality adjustments. If your pay path is steadily upward, your last 36 months will be your best 36 months. But the rule is flexible enough to look earlier if your pay falls later because of a downgrade, a move to lower locality, or part-time work.
The high-3 matters because the FERS formula uses it for life. A $10,000 increase in high-3 does not produce a one-time bump. With 30 years of service, it adds $3,000 per year at the 1.0% multiplier or $3,300 per year at the 1.1% multiplier. Over a 25-year retirement, that can mean $75,000–$82,500 before COLA effects.
For GS employees, basic pay generally includes base pay plus locality pay. This is why moving from a lower-locality area to Washington-Baltimore, San Francisco, New York, or another high-locality area can raise your pension base if the move occurs during your high-3 window. The number you want is usually the annual basic pay shown on your SF-50 and leave and earnings statement.
Most extra payments do not count. Overtime, bonuses, performance awards, travel reimbursements, cash awards, and many types of premium pay are excluded from high-3. This surprises employees who work heavy overtime late in their careers. Overtime can increase current cash flow, but it usually does not increase the FERS pension calculation.
| Pay type | Usually counts? | Notes |
|---|---|---|
| Base GS salary | Yes | Core pensionable pay |
| Locality pay | Yes | Included in basic pay |
| Overtime | No | Usually excluded |
| Cash awards | No | Usually excluded |
| Bonuses | No | Usually excluded |
The simplest planning estimate is to average your annual basic pay for the final three years. If your pay changed during those years, weight each pay rate by how long it applied. A January raise affects nearly the full year; a December promotion affects only one month in that year. Official calculations are more precise than simple calendar averages, but the calendar method is usually close for planning.
Year 1 basic pay: $132,000
Year 2 basic pay: $138,000
Year 3 basic pay: $146,000
Estimated high-3: (132,000 + 138,000 + 146,000) / 3 = $138,667
If you receive a promotion midway through the 36-month window, weight the old and new rates by month. Example: six months at $135,000 and thirty months at $150,000 produces a 36-month average of $147,500, not $150,000. This is why the timing of a promotion matters: the earlier it lands in your final three years, the more of it flows into high-3.
A late-career promotion has two effects. First, it increases your current salary. Second, if held long enough, it raises your high-3 and therefore your lifetime pension. That second effect is often underappreciated because the promotion's retirement value arrives slowly through monthly annuity checks.
Old projected high-3: $130,000
New projected high-3 after promotion: $145,000
Difference: $15,000
At 30 YOS and 1.1% multiplier: 15,000 x 30 x 0.011 = $4,950/year extra pension.
The promotion is most valuable if you stay long enough for the new pay to occupy most or all of your 36-month high-3 period. Retiring shortly after a promotion still helps, but not as much as staying three full years. This creates a common planning question: should you work long enough after a promotion to let the high-3 fully reset? The answer depends on health, job satisfaction, TSP readiness, FEHB eligibility, and how close you are to the age 62 multiplier.
High-3 can become complicated when your pay history is not a smooth upward line. If you take a downgrade late in your career, your high-3 may remain an earlier 36-month period. If you move from a high-locality area to a lower-locality area before retirement, your final salary may be lower than an earlier pay period. If you work part-time, OPM rules can prorate annuity computation in ways a simple full-time calculator will not capture.
Leave without pay and breaks in service can also affect the record. Short periods may have little impact; longer or unusual periods should be reviewed with HR. Special pay systems can have their own details. If your career includes VA special salary rates, law enforcement premium pay, or other special categories, use agency retirement estimates as a cross-check.
The planning rule: use HighThree for scenario modeling, but verify unusual situations before making an irreversible retirement date decision. A one-month misunderstanding in high-3 usually does not change much; a multi-year part-time or downgrade situation can.
Model promotions, raises, and retirement timing in the estimator.