FERS Retirement Calculator

Start with your high-3 salary, the average of your highest three consecutive years of basic pay under the rules that apply to your service. Enter your current age, planned retirement age, and years of service. The calculator adds the years between your current age and retirement age to your service figure. This assumes you keep working and accruing service until the planned retirement date.

Next enter your current TSP balance, assumed annual investment return, and withdrawal rate. The return projects the balance forward before retirement; the withdrawal rate estimates an initial annual income from that balance. Enter your estimated monthly Social Security benefit and the age you expect to start it. The calculator also asks for life expectancy, inflation, and a COLA assumption.

Use your own agency and personal records where possible. The OPM retirement services page explains federal retirement eligibility and annuity rules. The TSP provides account information and plan guidance, while the Social Security Administration explains how claiming age affects benefits.

The default example assumes a $115,000 high-3 salary, 25 years of service now, age 50 today, and retirement at 62. The calculator adds 12 years to service: 25 + (62 − 50) = 37 years at retirement. Since the assumed retirement age is at least 62 and projected service is at least 20 years, it applies a 1.1% annuity multiplier.

The annuity calculation is $115,000 × 37 × 1.1% = $46,805 per year. Dividing by 12 gives $46,805 ÷ 12 = $3,900 per month after rounding. The TSP estimate grows the current $350,000 balance at 6% for 12 years: $350,000 × 1.06¹² = about $704,269. Applying a 4% withdrawal rate gives $704,269 × 4% = about $28,171 per year, or $2,348 per month.

The headline total of $8,448 per month combines the annuity, estimated TSP income, and the full assumed Social Security benefit of $2,200 per month. The annual calculation is $46,805 + $28,171 + $26,400 = $101,376, then $101,376 ÷ 12 = $8,448. The income replacement result is $101,376 ÷ $115,000 = about 88%.

There is a timing detail worth checking: the headline total includes the Social Security benefit even if your selected start age is later than your retirement age. In the year-by-year table, the Social Security column starts only when you reach the selected Social Security age. With the defaults, the table shows no Social Security at age 62 and starts it at 67. Treat the headline total as a combined income estimate, not necessarily the amount available in your first retirement year.

The table projects 28 years, from age 62 through age 89. Its first row shows $74,976 of income at 62 from the annuity and TSP, before Social Security begins. Its last row at age 89 shows $134,462 in nominal total income and $69,033 in today’s dollars. The “Real (Today)” amount adjusts for the 2.5% inflation assumption; nominal future dollars and current purchasing power are not equivalent.

FERS retirement eligibility depends on age and creditable service, not just the size of the estimated annuity. Common immediate retirement routes include minimum retirement age (MRA) with 30 years of service, age 60 with 20 years, and age 62 with at least 5 years. MRA varies by birth year and generally falls between 55 and 57. The calculator’s simplified eligibility check does not replace OPM’s review of your record.

For most FERS employees, the basic annuity formula uses 1% of high-3 salary for each year of service. The formula generally uses 1.1% when you retire at age 62 or later with at least 20 years of service. Under the defaults, the calculator therefore applies the higher multiplier. See OPM’s FERS annuity computation guidance.

An MRA+10 retirement can have an age reduction when you start the annuity before age 62. The reduction is generally 5% for each year under 62, with partial years prorated. The calculator models a simplified reduction for certain MRA-age retirements with 10 to fewer than 30 years of service. It does not model every choice, such as postponing an annuity start date to reduce or avoid the age reduction.

This calculator’s simplified early-retirement rules should not be treated as an eligibility determination. Special provisions, military service deposits, unused sick leave, part-time service, and prior federal service may affect an official calculation. You can compare a different government pension using the CSRS Retirement Calculator or Military Retirement Calculator.

The TSP projection assumes a steady annual return. Actual markets fluctuate, so the projected $704,269 is not guaranteed. The model also uses the same assumed return before and after retirement when projecting the table’s balance, while income is estimated using a fixed withdrawal amount. That is a simplified illustration, not a personalized withdrawal schedule. Test alternative withdrawal amounts with the Retirement Withdrawal Calculator or compare strategies with the Retirement Withdrawal Strategy Calculator.

The 4% withdrawal rate is an input, not a promise that the portfolio will last for a specific period. Investment returns, inflation, taxes, fees, and the order of market gains and losses all influence sustainability. TSP withdrawals may also be taxable depending on account type and distribution. For practical tax-order considerations, read how to withdraw from retirement accounts tax-efficiently.

Social Security is a separate estimate. The calculator does not calculate your benefit from your earnings record; it uses the monthly amount you enter. Benefits depend on covered earnings and claiming age. Use your Social Security statement or the SSA retirement estimator to refine that input.

FERS COLAs and purchasing-power adjustments are not always equal to full inflation. For many FERS retirees, the COLA is subject to a formula that can be less than the Consumer Price Index increase. The calculator accepts a single COLA rate and applies it as a steady assumption, so it may overstate or understate future annuity purchasing power. The inflation and COLA fields are separate for this reason.

Projected service = years of service now + (retirement age − current age)

Annual FERS annuity = high-3 salary × projected service × annuity multiplier

The multiplier is 1% in the standard case and 1.1% in the calculator when retirement age is at least 62 and projected service is at least 20 years. A modeled early-retirement reduction is applied afterward when its conditions are met.

TSP at retirement = current TSP balance × (1 + annual return) ^ years to retirement

Estimated TSP annual income = TSP at retirement × withdrawal rate

The calculator adds the annual annuity, annual TSP income, and the entered annual Social Security amount for its headline income estimate. The year-by-year table separately observes the selected Social Security start age.

The result depends on choices about retirement timing, service, and investment return. These examples show how to use the inputs for scenario testing; they are not additional calculator outputs.

Do not assume that retiring later always improves every part of the plan. It may increase the annuity and TSP balance, but it also changes the length of retirement, health-insurance needs, and the date you can use other benefits. The FERS Annuity Supplement Calculator can help examine another potential income source for eligible retirees. For an overall savings target, compare your results with a retirement goal projection.

Does this estimate guarantee my FERS annuity?

No. It is a simplified estimate based on the inputs you provide. OPM calculates benefits using your official service history, salary record, retirement eligibility, and elections.

Why is the headline monthly income higher than the first year in the table?

The headline combines the entered Social Security benefit with the annuity and TSP estimate. The table delays Social Security until the selected start age, so the age-62 row excludes it under the default age-67 start.

Is the 1.1% multiplier automatic at age 62?

No. The calculator applies it when retirement age is at least 62 and projected service is at least 20 years. Confirm that your retirement type and service meet the applicable rules with OPM.

Does the TSP withdrawal estimate include taxes?

No. It estimates gross income from a percentage of the projected TSP balance. Tax treatment depends on account type, distribution, and your full tax situation. See how are 401(k) withdrawals taxed in retirement for general retirement-account tax context.

Should I use a 4% withdrawal rate or a different rate?

A 4% rate is only one planning assumption. A lower rate reduces estimated income but can leave a larger cushion; a higher rate raises initial income but can increase the risk of depleting savings. Compare multiple rates and test your spending against a longer retirement.

Does the COLA input match the actual FERS COLA?

Not necessarily. It is a flat percentage assumption for projection purposes. Actual FERS COLAs follow statutory rules and may differ from inflation, particularly for retirees below age 62 and in years when inflation is high.

Should I include all federal service in years of service?

Use creditable service under the rules that apply to your record. Deposits, redeposits, military service, part-time work, and refunded contributions can affect credit. Check your agency records and OPM guidance rather than assuming every calendar year counts.

Verify your service history and high-3 estimate, then run conservative and optimistic TSP-return scenarios. Separate income available at retirement from income that begins later, especially Social Security. Finally, compare estimated gross income with taxes, health insurance, housing, and other spending in a retirement needs analysis and a detailed retirement budget. Use the projection to identify questions for your benefits office—not as a substitute for an official annuity estimate.