Federal Retirement Calculator: $5,955/mo on a $120K FERS Salary — 2026
Use this guide to understand the assumptions, inputs, results, and next steps behind the calculator.
Created by Luis Gonzalez · Last updated September 15, 2026
A 52-year-old FERS employee earning $120,000 with 20 years of service retires at 62 with 30 projected years and a High-3 of $140,618. The annuity is $140,618 × 30 × 1.1% = $46,404/yr ($3,867/mo), TSP grows from $400,000 to $716,339 producing $2,388/mo, and after $300/mo FEHB the net is $5,955/mo. This calculator projects your salary and years of service to retirement, computes the annuity using your projected High-3, applies the FERS diet COLA (or full CSRS COLA), inflates Social Security, and models TSP drawdown with an option for inflation-adjusted withdrawals. It also estimates the FERS special retirement supplement, models sick leave credits, survivor benefit reductions, and identifies your Minimum Retirement Age (MRA) based on your birth year.
This tool is designed for federal employees who want to understand their potential retirement income. Whether you're planning your retirement date, deciding how much to save in your TSP, or determining when to claim Social Security, this calculator provides a realistic picture. For a more detailed look at your TSP, use the TSP match calculator. To explore different Social Security scenarios, try the Social Security calculator.
The results provide a year-by-year projection showing nominal income from each source, today's-dollar purchasing power, TSP balance trajectory, and FEHB cost growth. Charts illustrate how your income sources combine over time and how your TSP balance is projected to change throughout retirement.
How To Use This Federal Retirement Calculator
Begin by selecting your Retirement System — FERS or CSRS. Most employees hired after 1984 are under FERS.
Enter your Current Annual Salary and Annual Raise percentage. The calculator projects your salary forward to retirement and averages the last 3 years to compute your High-3 salary — no need to calculate it yourself.
Input your Years of Service as of today and your Current Age and Retirement Age. The calculator automatically adds the years between now and retirement to project your total service at retirement. The FERS 1.1% enhanced multiplier is applied when your projected service reaches 20+ years at age 62+.
Move to the Thrift Savings Plan (TSP) section. Provide your current TSP balance, expected return, and withdrawal rate. Check "Inflation-adjust TSP withdrawals" if you want your withdrawals to increase each year with inflation rather than staying flat.
Complete the Social Security section with your estimated monthly benefit in today's dollars. The calculator inflates this to your start age using your inflation assumption, then applies annual COLA increases during retirement.
Open Advanced Options to add unused sick leave hours (converted to service credit at 2,087 hours per year), choose a survivor benefit election, adjust FEHB premiums, or change the inflation rate.
Results update automatically as you adjust inputs.
What Each Input Means
Retirement System
FERS (Federal Employees Retirement System) uses a 1% or 1.1% multiplier, includes Social Security, and applies a "diet COLA" starting at age 62. CSRS (Civil Service Retirement System) uses a tiered formula (1.5%/1.75%/2%), may not include Social Security, and provides full CPI COLAs from the first year of retirement. Most employees hired after 1984 are under FERS.
Current Salary & Annual Raise
Your current basic pay is projected forward using the annual raise rate. The calculator averages the last 3 years of projected salary to produce your High-3 average salary — the foundation of the annuity formula. For most employees, GS step increases and locality pay adjustments average 2–3% per year.
Years of Service
Your creditable service today. The calculator adds the years between your current age and retirement age, plus any sick leave credit, to project total service at retirement. Each additional year of service directly increases your annuity.
Sick Leave Hours
Unused sick leave converts to service credit at retirement. The conversion is: hours ÷ 2,087 = years of additional service. For example, 1,000 hours of sick leave adds approximately 0.48 years to your service total. This credit applies to the annuity calculation but does not count toward eligibility requirements.
Retirement Age & Current Age
Your retirement age determines when income begins. Your current age determines how many years remain for TSP growth and salary projection. The calculator uses your birth year (2026 minus current age) to determine your Minimum Retirement Age (MRA).
TSP Balance, Return & Withdrawal Rate
The Current TSP Balance grows at your expected return until retirement. The Withdrawal Rate is applied to the balance at retirement to determine annual income. By default, withdrawals are level nominal dollars. Check "Inflation-adjust TSP withdrawals" to increase withdrawals each year with inflation — this provides stable purchasing power but depletes the balance faster.
Social Security Benefit & Start Age
Enter your estimated monthly benefit in today's dollars. The calculator inflates this to your start age at the inflation rate, then applies annual COLA during retirement. You can get your personalized estimate from SSA.gov. CSRS employees who didn't pay into Social Security should enter $0.
Survivor Election
A survivor benefit provides your spouse with a portion of your annuity after your death, but reduces your annuity while you're alive:
- Full (50% to survivor): Reduces your annuity by 10%
- Partial (25% to survivor): Reduces your annuity by 5%
- None: No reduction, but no survivor annuity
Married FERS employees default to full survivor benefit unless the spouse consents to a waiver.
Advanced Options
- Life Expectancy: Planning assumption for how long your retirement lasts.
- FEHB Monthly Premium: Your Federal Employees Health Benefits cost, increasing with inflation each year.
- Inflation Rate: Drives FEHB cost growth, Social Security COLA, and (for FERS) the diet COLA calculation.
- Sick Leave Hours: Converted to service credit (hours ÷ 2,087).
How The Calculator Works
High-3 Salary Projection
Rather than using today's salary as the High-3, the calculator projects your pay forward:
salary(year) = current_salary × (1 + annual_raise)^year
high_3 = average of salary in the last 3 years before retirement
This gives a realistic annuity estimate that accounts for future pay growth.
Service Projection
total_service = current_years + (retirement_age - current_age) + (sick_leave_hours / 2087)
The annuity uses this projected total, not today's years of service.
FERS Annuity Formula
multiplier = IF(retirement_age >= 62 AND total_service >= 20, 1.1%, 1.0%)
annual_annuity = projected_high_3 × total_service × multiplier
CSRS Annuity Formula
CSRS uses a tiered multiplier that increases with service:
annual_annuity = high_3 × (first_5_years × 1.5% + next_5_years × 1.75% + remaining_years × 2.0%)
annual_annuity = min(annual_annuity, high_3 × 80%) // CSRS cap
Survivor Reduction
full_survivor: annuity × 0.90 (10% reduction → 50% to survivor)
partial_survivor: annuity × 0.95 (5% reduction → 25% to survivor)
FERS Diet COLA (Starting at Age 62)
FERS COLAs are not full CPI. The "diet COLA" formula:
IF CPI ≤ 2%: COLA = CPI
IF 2% < CPI ≤ 3%: COLA = 2%
IF CPI > 3%: COLA = CPI - 1%
COLAs begin the year after you turn 62. Before 62, the annuity is level. At 2.5% inflation, the FERS COLA is only 2% — a 0.5 percentage point annual gap that compounds over time.
CSRS annuities receive full CPI COLA from the first year of retirement.
FERS Special Retirement Supplement
Estimated for eligible retirees (MRA+30 or age 60+20) retiring before 62:
supplement = (total_fers_service / 40) × estimated_SS_benefit_at_62
The SS benefit at 62 is estimated at 70% of the benefit at full retirement age (67). The supplement ends at age 62 and is subject to an earnings test.
Social Security Inflation
SS benefits are entered in today's dollars and inflated to the start age:
ss_at_start = monthly_benefit × 12 × (1 + inflation)^(start_age - current_age)
During retirement, SS receives full CPI COLA each year from the start age.
TSP Projection
tsp_at_retirement = current_balance × (1 + return)^years_to_retirement
annual_withdrawal = tsp_at_retirement × withdrawal_rate
Each year in retirement:
tsp_balance = tsp_balance × (1 + return) - withdrawal
If inflation-adjusted: withdrawal increases by inflation each year
Minimum Retirement Age (MRA)
Your MRA is determined by your birth year:
| Birth Year | MRA |
|---|---|
| Before 1948 | 55 |
| 1948–1952 | 55 + 2 months per year after 1947 |
| 1953–1964 | 56 |
| 1965–1969 | 56 + 2 months per year after 1964 |
| 1970 or later | 57 |
The FERS Three-Legged Stool Explained
The Federal Employees Retirement System (FERS) is designed as a portable and flexible system with three distinct components, often called the "three-legged stool."
1. FERS Basic Benefit (Annuity) A defined benefit pension based on your High-3 salary and years of service. The 1% (or 1.1%) multiplier produces a guaranteed monthly payment for life, with diet COLAs starting at age 62.
2. Thrift Savings Plan (TSP) A defined contribution plan similar to a private-sector 401(k). Your agency contributes 1% automatically and matches up to 4% more (5% total with your 5% contribution). The 2026 TSP elective deferral limit is $24,500. Employees age 50+ can add an $8,000 catch-up ($32,500 total). Under the SECURE 2.0 super catch-up, employees ages 60-63 can contribute $11,250 instead ($35,750 total).
3. Social Security FERS employees pay into Social Security and earn benefits based on their earnings history. CSRS employees generally do not, which is why CSRS annuities are larger — they compensate for the lack of Social Security.
CSRS vs. FERS: Key Differences
| Feature | FERS | CSRS |
|---|---|---|
| Annuity multiplier | 1.0% (1.1% at 62+/20 yrs) | 1.5%/1.75%/2.0% tiered |
| Annuity cap | None | 80% of High-3 |
| COLA | Diet COLA starting at 62 | Full CPI from retirement |
| Social Security | Yes | Generally no |
| TSP match | Up to 5% | No match |
| Employee contribution | 4.4% of pay (FERS-FRAE) | 7.0% of pay |
FERS Retirement Eligibility
To receive an immediate, unreduced FERS annuity:
- Age 62 with 5 years of service: Standard eligibility, enhanced 1.1% multiplier if 20+ years
- Age 60 with 20 years of service: Earlier retirement with standard 1.0% multiplier
- MRA with 30 years of service: Earliest unreduced retirement
Early retirement at MRA with 10+ years is possible, but the annuity is reduced by 5% for each year under age 62.
Understanding Your Results
- Net Monthly Income: Combined income from all sources minus FEHB premiums.
- Annuity: Computed from your projected High-3 and projected service years, with survivor reduction if elected.
- TSP at Retirement: Your current balance grown to retirement. The withdrawal creates monthly income.
- Income Replacement: How your net retirement income compares to your projected High-3 salary.
- FERS Supplement card: Shown when eligible — estimates the monthly supplement from retirement until age 62.
- Today's $ column: Shows the purchasing power of your net income in current dollars, accounting for inflation from today.
- MRA insight: Identifies your Minimum Retirement Age based on your birth year.
- Diet COLA insight: Shows the actual COLA rate your FERS annuity receives vs. full inflation.
Ways To Improve Your Results
- Work Longer: Each additional year increases both your service time and High-3 salary, compounding the annuity formula. It also gives your TSP another year to grow.
- Increase TSP Contributions: Get the full 5% agency match at minimum. The 2026 elective deferral limit is $24,500 ($32,500 with the $8,000 catch-up at age 50+, or $35,750 with the $11,250 super catch-up at ages 60-63).
- Delay Social Security: Waiting from 62 to 67 or 70 significantly increases your monthly benefit. The FERS supplement can bridge the gap.
- Preserve Sick Leave: Each 2,087 hours of unused sick leave adds a full year of service credit to your annuity at retirement.
- Target the 1.1% Multiplier: If you're close to 20 years of service, working until 62 increases your multiplier from 1.0% to 1.1% — a 10% annuity boost.
Common Mistakes in Federal Retirement Planning
- Using Today's Service Years: A 52-year-old with 20 years who retires at 62 will have 30 years of service, not 20. This calculator projects the total.
- Assuming Full CPI COLA Under FERS: FERS diet COLA at 3% inflation is only 2% — that 1% gap compounds significantly over a 25+ year retirement.
- Missing the TSP Match: Not contributing at least 5% forfeits part of the agency's matching contribution.
- Ignoring the Survivor Election: The default full survivor benefit reduces your annuity by 10%. If your spouse has their own retirement income, the partial or no election may be appropriate.
- Forgetting Sick Leave Credit: Unused sick leave is valuable — it adds to your service total at retirement without affecting eligibility.
- Not Inflating Social Security: Today's SS estimate is in current dollars. By the time you collect, the actual dollar amount will be higher due to annual COLAs.
- Investing TSP Too Conservatively: The G Fund is safe but may not outpace inflation over a long career. The C, S, and I Funds offer higher growth potential.
Start Planning Your Federal Retirement
Understanding your future income is the first step toward a secure retirement. Use the calculator above to see how salary growth, service projections, the diet COLA, and your TSP combine for a realistic estimate.
For a comprehensive plan including expenses, taxes, and healthcare costs, try the main retirement calculator. Explore all our retirement calculators and the learning center to build a confident retirement plan.
Frequently Asked Questions
Quick answers to the questions people usually have after running the retirement calculator.
1How is the FERS annuity calculated?
The formula is: projected High-3 salary × total service years × multiplier (1.0% or 1.1%). The 1.1% multiplier applies if you retire at age 62 or later with 20+ years. This calculator projects both salary and service to your planned retirement date.
2What is the FERS diet COLA?
FERS COLAs start at age 62 and are less than full CPI: you get full CPI up to 2%, capped at 2% when CPI is between 2% and 3%, and CPI minus 1% when inflation exceeds 3%. At 2.5% inflation, your COLA is only 2%.
3What is the FERS special retirement supplement?
A monthly payment that bridges the gap between retirement and age 62 for eligible employees (MRA+30 or age 60+20). It approximates your Social Security benefit earned during federal service: (FERS service years ÷ 40) × SS benefit at 62. It ends at age 62 and is subject to an earnings test.
4How does sick leave convert to service credit?
Unused sick leave hours are divided by 2,087 to produce years of additional service. This credit applies to the annuity calculation but does not count toward eligibility requirements (like the 20-year threshold for the 1.1% multiplier).
5What is the difference between FERS and CSRS?
CSRS uses a more generous tiered formula (1.5%/1.75%/2%) and provides full CPI COLA from retirement, but generally doesn't include Social Security. FERS uses a simpler 1%/1.1% formula with diet COLA but includes Social Security and TSP matching.
6What is the Minimum Retirement Age (MRA)?
Your MRA depends on your birth year — it ranges from 55 (born before 1948) to 57 (born 1970 or later). You can retire at your MRA with 30 years of service for an unreduced benefit, or at MRA with 10 years with a 5% per year reduction.
7How does the survivor benefit work?
Electing a survivor benefit reduces your annuity while you're alive but provides your spouse with continuing income after your death. Full survivor (50%) costs 10% of your annuity; partial (25%) costs 5%. Married FERS employees default to full unless the spouse waives it.
8Can CSRS employees collect Social Security?
CSRS employees who paid into Social Security through other employment may receive benefits, but they're often reduced by the Windfall Elimination Provision (WEP). Enter $0 for Social Security if you don't expect to receive benefits.
9Does this calculator model early-retirement reductions?
No. If you retire before meeting unreduced eligibility (age 62/5 years, age 60/20 years, or MRA/30 years), your annuity may be reduced by 5% per year under age 62. This calculator shows the unreduced annuity — verify your eligibility with your HR office.
10How much should I have in my TSP by retirement?
It depends on your spending needs and other income. A common goal is a large enough TSP so that a 4% withdrawal rate fills the gap between your expenses and your annuity/Social Security income. Use the retirement calculator for a comprehensive analysis.