Federal retirement math can feel like a trap. You hear “high-3” and suddenly you’re digging through pay stubs, LES lines, and old SF-50s. The good news: you can figure it out. And once you know your high three average salary, you can make smarter choices about when to retire, when to promote, or whether to take that last job change. If you want the fastest answer, a high-3 calculator like the free one at IsMyJobWorthIt.com can do the heavy lifting and show your personal numbers in minutes.
Background: What “High-3” Really Means (and Why You Should Care)
“High-3” means your highest average basic pay over any 36 consecutive months (3 years). It’s used to compute retirement benefits for many people in two big groups:
- Federal employees under FERS or CSRS (your “high-3 salary federal” number is a key input)
- Military members under the High-3 retirement system (often called “military high-3”)
Here’s why it matters: your pension is usually a percentage of your high-3, multiplied by years of service.
Federal (FERS) quick version
A common FERS formula is:
- 1% × high-3 × years of creditable service
- Or 1.1% if you retire at 62+ with 20+ years
OPM explains the basics here: OPM FERS computation.
Military quick version
For the military High-3 system, the pension is generally:
- 2.5% × years of service × high-3 average basic pay
For military pay info and rules, start with DFAS and Military OneSource.
What “counts” as pay is the whole game
This is where people get burned. For federal employees, “basic pay” is not the same as your total earnings. For military, “basic pay” also has a specific meaning. If you include the wrong items, your estimate will be way off.
If you want a quick way to test different dates and pay lines, the tool at IsMyJobWorthIt.com is often the easiest way to get your exact numbers without building a spreadsheet.
Main Content 1: High-3 Salary Federal — What Counts (and What Does Not)
Let’s break down what usually counts for a high-3 salary federal calculation.
Counts (most of the time)
For most GS and many pay systems, your high-3 uses basic pay, which often includes:
- Your GS base rate
- Your locality pay (because it is part of basic pay for retirement)
- Some forms of special rate pay (like certain SSR tables)
You can verify your current pay table on OPM Pay Tables.
Usually does NOT count
These are common “gotchas”:
- Overtime
- Bonuses/awards
- Cash performance awards
- Travel per diem
- Night differential (for most)
- Hazard pay
- Recruitment/relocation/retention incentives (often not basic pay for retirement)
If you’re unsure, your SF-50 and your agency HR can help, and OPM is the source of truth: OPM.gov.
A simple federal example (step-by-step)
Say you are a GS employee and your basic pay (including locality) for three years was:
- Year 1: $92,000
- Year 2: $95,000
- Year 3: $99,000
Your high three average salary is:
- Add them: $92,000 + $95,000 + $99,000 = $286,000
- Divide by 3: $286,000 ÷ 3 = $95,333.33
Now estimate a FERS pension with 25 years:
- 1% × $95,333.33 × 25 = $23,833/year (about $1,986/month)
That’s why a small change in high-3 can matter for the rest of your life.
Timing tip for federal employees
Because high-3 is any 36 consecutive months, your best 3 years might not match calendar years. A mid-year promotion or step increase can shift the “best 36 months” window.
For more pay and retirement coverage, FedInfo readers often also look at federal pay basics and federal benefits.
Main Content 2: Military High-3 — What Counts, and How Timing Changes It
For military high-3, the key phrase is basic pay. That generally means your base pay from the pay charts, not your full LES.
Counts for military High-3
Typically included:
- Basic pay only (the base pay table amount)
Usually does NOT count
Common items that do not go into the High-3 average:
- BAH (housing allowance)
- BAS (food allowance)
- Special pays (many types)
- Bonuses
- Combat zone tax benefits (tax is separate from the retirement base)
DFAS is a solid starting point for pay and LES questions: DFAS. Military.com also has helpful explainers: Military.com.
A military example (why the last promotion matters)
Let’s say you retire at 20 years. Your pension multiplier is:
- 2.5% × 20 = 50%
Now imagine your last 36 months of basic pay average to $6,400/month.
- Pension = 50% × $6,400 = $3,200/month
But what if you pick up a promotion late and your last 36 months average becomes $6,750/month?
- Pension = 50% × $6,750 = $3,375/month
That’s $175 more per month, or $2,100 per year, for life (plus COLA rules).
Timing tip for military members
Your “best 36 months” is often the last 36 months, but not always. If you had a temporary reduction, a break in service, or a weird pay change, it can shift.
If you want to run “what if I retire in June vs December?” scenarios, a high-3 calculator like IsMyJobWorthIt.com can save you hours.
Practical Examples: Side-by-Side Scenarios With Real Numbers
Here are a few real-world style scenarios to show how high-3 changes.
Example 1: Federal GS employee who moves to a higher locality
You are GS-12 and you move from a lower locality to a higher one.
- Old basic pay (with locality): $96,000
- New basic pay (with locality): $104,000
If your best 36 months become:
- 12 months at $96,000
- 24 months at $104,000
High-3 average:
- (1 year × $96,000) + (2 years × $104,000)
- $96,000 + $208,000 = $304,000
- $304,000 ÷ 3 = $101,333.33
With 30 years under FERS at 1%:
- 1% × $101,333.33 × 30 = $30,400/year (about $2,533/month)
If you had stayed at $96,000 for all 3 years:
- High-3 = $96,000
- Pension = 1% × $96,000 × 30 = $28,800/year
That move could mean about $1,600 more per year in pension.
Example 2: Federal employee at 62 with 20 years (the 1.1% bump)
Say your high-3 is $110,000 and you retire at 62 with 20 years.
- Pension = 1.1% × $110,000 × 20
- = 0.011 × $110,000 × 20
- = $1,210 × 20
- = $24,200/year (about $2,017/month)
If you retired earlier and only got 1%:
- 1% × $110,000 × 20 = $22,000/year
That’s $2,200/year difference just from timing.
Example 3: Military E-7 retiring at 20 vs 22 years
Assume your High-3 average basic pay is $6,200/month.
- At 20 years: 2.5% × 20 = 50%
- Pension: 50% × $6,200 = $3,100/month
- At 22 years: 2.5% × 22 = 55%
- Pension: 55% × $6,200 = $3,410/month
That extra 2 years adds $310/month.
Example 4: Military member promotes late in the last 3 years
Your last 36 months include:
- 18 months at $5,900/month
- 18 months at $6,700/month
High-3 average:
- (18 × $5,900) + (18 × $6,700)
- $106,200 + $120,600 = $226,800
- $226,800 ÷ 36 = $6,300/month
At 20 years (50%):
- 50% × $6,300 = $3,150/month
This is why the “last promotion push” can pay off.
Common Mistakes and Misconceptions (That Cost Real Money)
- Mistake 1: Using total pay instead of basic pay. For federal, overtime and awards usually don’t count. For military, BAH and BAS don’t count.
- Mistake 2: Averaging calendar years only. High-3 is any 36 consecutive months. A mid-year raise can change the best window.
- Mistake 3: Forgetting the 1.1% FERS rule at 62. If you’re close, that timing can be worth thousands per year.
- Mistake 4: Not saving proof. Keep SF-50s, pay stubs, and LES copies. Fixing errors later is painful.
- Mistake 5: Guessing instead of checking tables. Use OPM pay tables and DFAS when you’re unsure.
For news and practical angles, you can also compare what you’re hearing with outlets like FedWeek, GovExec, Federal Times, and Military.com. They’re not official, but they often explain changes in plain language.
Step-by-Step: How to Calculate Your High-3 (Without Losing Your Mind)
Step 1: Gather your pay records
Federal:
- SF-50s for promotions/steps
- A few years of pay stubs
- Your pay table from OPM
Military:
- LES history
- Basic pay charts (DFAS links from DFAS)
Step 2: Identify what pay counts
- Federal: look for basic pay (often includes locality)
- Military: use basic pay only
If you’re not sure, confirm on OPM.gov or with DFAS.
Step 3: Find your best 36 consecutive months
- Write down each pay rate and the dates it applied.
- Build a 36-month window and total it up.
- If you had raises, test windows that start right after a raise.
Step 4: Do the math
- Add up the pay for those 36 months.
- Divide by 3 (annual) or by 36 (monthly), depending on your data.
Step 5: Estimate your pension
- FERS: 1% (or 1.1%) × high-3 × years
- Military: 2.5% × years × high-3
Step 6: Sanity-check with a tool
If you want to avoid spreadsheet mistakes, run it through a high-3 calculator. The one at IsMyJobWorthIt.com is helpful because it’s fast, it’s free, and it lets you test “retire this date vs that date” without redoing all the math.
(And if student loans affect your retirement timing, it can also help to review repayment options at StudentAid.gov.)
Key Takeaways / Bottom Line
Your high-3 is not a mystery, but it is easy to mess up. The big rule is simple: it’s your highest paid 36 months, using the pay that counts for retirement. For federal employees, that usually means basic pay including locality, not overtime or bonuses. For military members, it’s usually basic pay only, not BAH or BAS. Small timing choices—like retiring after a raise or hitting age 62 with 20 years—can change your pension for life. Try the calculator at IsMyJobWorthIt.com to see your personal results, then double-check details with OPM.gov and DFAS.