FERS Retirement Calculator Estimate Your Federal Pension.

The Math Behind the Calculator

How the FERS Pension Formula Works

Your FERS pension is calculated using a straightforward formula established by the Office of Personnel Management (OPM). While the math itself is simple, the variables that feed into it — your salary history, creditable service, and retirement age — involve nuances that can significantly affect your retirement income.

High-3 Average Salary

Your high-3 is the highest average basic pay you earned during any 36 consecutive months of federal service. For most employees, this is the final three years before retirement. Your high-3 includes your base salary and locality pay, but does not include overtime, bonuses, awards, or other premium payments.

If you took a lower-paying position later in your career — for example, moving from a GS-14 supervisory role to a GS-13 non-supervisory position — OPM will look at every possible 36-month window in your career and use whichever one produces the highest average. This means your high-3 could come from an earlier period rather than your final years.

Maximizing your high-3 is one of the most impactful retirement planning decisions you can make. A $5,000 difference in your high-3 translates to $50–$55 more per year for every year of creditable service — compounding over a 20–30+ year retirement.

Years of Creditable Service

Your creditable service includes all periods of federal civilian employment covered by FERS deductions, plus any additional service credit you may qualify for. This can include:

• All time in a FERS-covered position where retirement deductions were withheld
• Military service, if you complete a military service deposit (buyback)
• Unused sick leave, which is converted to service credit at the time of retirement
• Certain periods of temporary or intermittent employment, if deposits are made

The sick leave conversion is particularly important. OPM converts your unused sick leave balance into additional months and days of creditable service using a factor of 2,087 hours per year. For example, 2,087 hours of unused sick leave adds a full year of service credit to your annuity calculation. At 1,000 hours, you would receive approximately 5 months and 22 days of additional credit.

Unlike annual leave (which is paid out as a lump sum when you retire), sick leave directly increases your pension for the rest of your life.

The Multiplier: 1% vs. 1.1% vs. 1.7%

Enhanced multiplier qualification: To qualify for the 1.1% multiplier, you must actually be age 62 at the time of retirement. If you retire at 61 and later turn 62, you do not receive the enhanced multiplier.

Special category multiplier: Law enforcement officers, firefighters, and air traffic controllers receive the 1.7% multiplier for their first 20 years of covered service, then 1% for any years beyond 20. This recognizes the demanding nature of these positions and their earlier mandatory retirement ages.

Putting It Together: The Complete Calculation

For a standard FERS employee, the calculation flows like this:

1. Determine your high-3 average salary
2. Add up your total creditable service (including sick leave conversion and any military buyback)
3. Determine your multiplier based on your age and years of service at retirement
4. Multiply: High-3 × Total Years × Multiplier = Annual Pension

If you elect a survivor benefit for your spouse, your pension is then reduced by 5% (for 25% survivor benefit) or 10% (for 50% survivor benefit) to fund that protection.

The calculator above automates this entire process. Enter your numbers to see your estimated annual and monthly pension, then read the examples below to understand how different scenarios play out. For a complete walkthrough of eligibility rules, see our FERS retirement planning page.

Real-World Scenarios

FERS Pension Examples at Different Career Stages

Understanding the formula is one thing — seeing it applied to real federal salary levels makes the impact tangible. Below are four common scenarios using 2026 GS pay scales.

Bridge to Social Security

The FERS Supplement and Early Retirement Options

If you are planning to retire before age 62, the FERS supplement is a critical part of your income picture. It acts as a bridge payment that partially replaces Social Security income until you become eligible for actual Social Security benefits.

What Is the FERS Supplement?

The FERS supplement is a monthly payment that approximates the Social Security benefit you earned during your years of FERS-covered federal employment. It begins when you retire and ends at age 62 (or when you become eligible for Social Security, whichever comes first).

The supplement is only available to employees who retire on an immediate, unreduced annuity before age 62. This means you must meet one of these eligibility criteria:

• MRA + 30 years: You have reached your Minimum Retirement Age and have at least 30 years of creditable service
• Age 60 + 20 years: You are at least 60 years old with 20 or more years of creditable service

Employees who retire under the MRA+10 provision (Minimum Retirement Age with 10–29 years of service) do not receive the FERS supplement, and their pension is reduced by 5% for each year they are under age 62.

How Is the Supplement Calculated?

OPM estimates your supplement using this approach:

1. They calculate your estimated full Social Security benefit at age 62
2. They multiply that by a fraction: your years of FERS service divided by 40

This can represent significant income. In the GS-13 example above, the supplement could add $1,000–$1,500 per month to bridge the gap between retirement and Social Security eligibility.

Important Supplement Considerations

The FERS supplement is subject to an earnings test similar to Social Security. If you work after retiring and earn more than the annual exempt amount ($22,320 in 2025), your supplement is reduced by $1 for every $2 you earn above the limit. Your actual FERS pension is not affected by this earnings test — only the supplement.

The supplement also does not receive cost-of-living adjustments (COLAs). While your FERS pension receives annual COLAs after age 62, the supplement remains fixed at the amount calculated when you retire.

Planning Your Federal Retirement Timeline

Whether to retire at your MRA, wait until 60, or hold out for age 62 and the 1.1% multiplier is one of the most consequential financial decisions a federal employee faces. The difference can amount to hundreds of thousands of dollars over a 25–30 year retirement.

Our federal benefits team specializes in running these scenarios for FERS employees. We analyze your specific pension, supplement eligibility, TSP balance, Social Security timing, FEHB considerations, and tax implications to identify the optimal retirement date for your situation. Schedule a federal retirement analysis to get your personalized Retirement Money Map.

Beyond the Calculator

Your FERS Calculator Results Are Just the Beginning

Your FERS pension is one piece of a larger federal retirement picture. Explore these related benefits to build a complete retirement strategy.