How FERS Retirement Works: The Formula, the Dates and the Supplement

FERS pays from three sources: a basic annuity calculated from your service and your highest three consecutive years of average salary, the Thrift Savings Plan with its agency match, and Social Security. Whether the annuity is reduced depends on your age and years of service on the day you retire.

The three parts

The Federal Employees Retirement System was designed as a three-legged structure rather than a single pension. The basic annuity is the defined-benefit leg, paid by OPM for life. The Thrift Savings Plan is the defined-contribution leg, and for most FERS employees it ends up being the largest of the three. Social Security is the third, and unlike CSRS employees, FERS employees pay into it throughout their careers.

That design matters for planning because the three legs behave differently. One is fixed and lasts for life. One is a balance you manage and draw down. One is a benefit whose size depends heavily on when you claim it. A plan has to treat them as one system rather than three accounts.

This page covers the mechanics. How the pieces interact at retirement, and the elections that cannot be reversed, are covered in federal employee retirement planning.

Vesting, the first check

Before any of the arithmetic matters, you have to be vested in the basic annuity. For most FERS employees that takes five years of creditable civilian service. Agency automatic contributions to the TSP have their own vesting schedule, which is separate and usually shorter, and your own contributions and their earnings are always yours.

If you are near that five-year line, or if you have federal service from an earlier period in your career that you are not sure counts, that is worth confirming with your agency benefits office before you plan around anything else.

The basic annuity formula

The pension is computed from three inputs: your years and months of creditable service, your high-3 average salary, and a multiplier.

High-3 is the average of your highest three consecutive years of basic pay, which is usually but not always your final three years. Locality pay generally counts toward it. Overtime and bonuses generally do not.

The multiplier is where age and service interact. The standard FERS multiplier applies in most cases. A higher multiplier applies if you retire at 62 or later with at least 20 years of service, which is why for some people working a few additional months changes the calculation more than it looks like it should. Special provisions apply to law enforcement officers, firefighters and air traffic controllers, which use different multipliers and different retirement ages entirely.

This page describes how the calculation is structured rather than giving current multipliers, deposit rates or dollar figures, which change and vary by category. Get your own numbers from your agency benefits office or an OPM annuity estimate. This page is general information, not tax or legal advice.

Minimum retirement age

FERS has a minimum retirement age, usually written MRA, that depends on the year you were born. For employees born in 1970 or later it is 57. For those born before 1948 it was 55. The years in between step up in two-month increments, so people born in the 1950s and 1960s land somewhere between 55 and 57.

Reaching your MRA is not the same as qualifying for an unreduced annuity. That depends on the combination of age and service you hold on your retirement date.

The postponed and deferred rows are the ones people conflate, and the difference is consequential: postponing generally preserves the path back to federal health coverage, deferring generally does not. Those insurance consequences are covered in FEHB, FEGLI and survivor elections.

The TSP leg

The Thrift Savings Plan is the part of FERS you actually control. FERS employees receive an automatic agency contribution regardless of whether they contribute, plus matching on the first portion of their own contributions, which is the single best-understood piece of the system and still the most commonly left on the table.

Two mechanics are worth knowing before you retire. Front-loading contributions early in the year can cause you to hit the annual limit before December and miss matching in the final pay periods, so most people are better off spreading contributions across the year. And the traditional and Roth balances inside the TSP are treated differently at withdrawal, which matters for the order you draw from them later.

What you can do with the balance at separation, and how a rollover is taxed, are covered in TSP rollover options.

The annuity supplement

If you retire before 62 with an immediate, unreduced annuity, you may also receive the FERS annuity supplement. It approximates the Social Security benefit earned during your federal service and is paid by OPM until you turn 62.

Two things about it surprise people. It ends at 62 whether or not you claim Social Security then, so the two decisions are separate. And it is subject to an earnings test, so post-retirement work above an annual limit reduces it. If a second career is in your plans, model that before accepting the job rather than after.

Note that the supplement generally does not accompany an MRA plus 10 retirement, which is one more reason that category deserves careful arithmetic.

What to gather before you plan

• A current annuity estimate from your agency benefits office, and your service computation date
• Confirmation of any service that requires a deposit or redeposit to count, including military service
• Your high-3 figure, and whether any pay periods you are assuming will actually be in it
• Your Social Security statement, for the claiming analysis that runs alongside this
• Your TSP balance split between traditional and Roth
• Your FEHB enrollment history for the five years before your intended date

Federal households in Westwood

Westwood is one of the smallest cities in Johnson County, tucked against the state line north of Rainbow Boulevard and a few minutes from our office. Small as it is, it sits in the middle of a metro with a substantial federal workforce, and the conversations we have there look like the ones everywhere else in northeast Johnson County: a service computation date, an annuity estimate, a TSP balance, and no single page showing how they combine into monthly income. Building that page is what our federal employee retirement planning does, alongside your agency benefits office rather than in place of it. See the communities we serve across the Kansas City area.

CFG Wealth Management Inc. is an independent firm based in Prairie Village, Kansas, led by LaMont Chandler, CRD 2794744. We are not affiliated with any other firm operating under a similar name. LaMont holds FINRA Series 7, 24 and NASAA Series 63, 65 registrations and has been registered in the securities industry since 1996. He is registered in Kansas, Missouri, Texas and Idaho. Securities and advisory services are offered through Madison Avenue Securities, LLC, member FINRA and SIPC, and a registered investment advisor. CFG Wealth Management Inc. and Madison Avenue Securities are not affiliated companies. His record is available on FINRA BrokerCheck.

Common questions

Where this connects

• Federal employee retirement planning: how the pieces fit together
• FERS vs CSRS: how the two systems differ
• FEHB, FEGLI and survivor elections
• TSP rollover options at separation
• Social Security alongside a federal pension
• More retirement planning insights