Military Service Buyback Calculator

Calculate the exact cost to buy back your military service time and see how it increases your federal FERS or CSRS pension. This calculator determines your total deposit, including any accrued interest, and projects the financial return on your investment. Find your increased monthly annuity, total lifetime gain, break-even point, and overall ROI to make an informed decision.

This tool is for current or former federal employees under the FERS or CSRS systems who also have prior active duty military service. If you are planning your overall federal retirement, use our FERS Pension Calculator to see your full annuity projection. You may also find the TSP Match Calculator useful for maximizing your workplace savings.

The calculator provides a complete financial analysis of your buyback decision. You will see a score summarizing the return on investment, a breakdown of the deposit cost, and charts showing how quickly the additional annuity income pays back your initial deposit. The results will help you understand whether buying back your military time is a financially sound move for your retirement plan.

Start by entering your military service details. The Total Military Base Pay is the total basic pay you earned during your service; you can find this on your earnings statements or by requesting it from the Defense Finance and Accounting Service (DFAS). Enter the Years of Military Service you plan to buy back and the Years Since Military Separation, which is used to calculate potential interest on your deposit.

Next, provide your federal retirement details. Your High-3 Average Salary is the average of your highest 36 consecutive months of basic pay and is a key factor in your pension calculation. Enter your planned Civilian Years of Service (without military time), your Current Age, and your Planned Retirement Age. These inputs help determine your total creditable service and eligibility for certain FERS benefits, like the enhanced 1.1% multiplier.

Finally, confirm your deposit details. The Deposit Rate is typically 3% for FERS employees and 7% for CSRS employees. The Interest Rate on Late Deposit is a variable rate set by the U.S. Treasury that applies after a two-year grace period. For a more detailed lifetime projection, open the advanced settings to adjust your Life Expectancy and the estimated annual Cost-of-Living Adjustment (COLA) Rate for your pension.

Total Military Base Pay

This is the sum of all basic pay you received during the period of military service you intend to buy back. It does not include allowances for housing, subsistence, or other special pays. The total base pay is the foundation for calculating your required deposit. Accurate records are essential for an exact calculation.

Years of Military Service

Enter the total number of years of active duty military service you wish to have credited toward your federal civilian retirement. This time is added directly to your civilian service years to calculate your total creditable service for your FERS or CSRS annuity.

Years Since Military Separation

This input is crucial for determining if interest is owed on your deposit. Federal employees have a two-year, interest-free grace period to make their deposit, which begins after they are first hired into a civilian position covered by FERS or CSRS. After two years, interest begins to accrue and is compounded annually.

High-3 Average Salary

Your "high-3" is the average of your highest 36 consecutive months of basic federal salary. This figure is used in the FERS and CSRS annuity formulas to determine your annual pension amount. A higher high-3 salary will result in a larger annuity increase from buying back your military years. You can project this using the FERS Pension Calculator.

Civilian Years of Service

This is the number of years you have worked or plan to work as a federal civilian employee, not including the military time you are considering buying back. The calculator will add your military years to this number to determine your total creditable service.

Current Age & Planned Retirement Age

Your ages are used to calculate the timeline for your retirement and the total duration your pension will be paid, which affects the lifetime value of the buyback. Retiring at age 62 or later with at least 20 years of total creditable service (including buyback) qualifies FERS employees for an enhanced 1.1% annuity multiplier instead of the standard 1.0%.

Deposit Rate

This is the percentage of your total military base pay that you must deposit to receive credit. For most federal employees who first entered service after December 31, 1983, under the FERS system, the rate is 3%. For employees under the older CSRS system, the rate is 7%.

Interest Rate on Late Deposit

If you do not pay your deposit within the two-year grace period, interest is charged on the unpaid balance. The rate is determined annually by the Department of the Treasury. This calculator uses a default rate, but you should verify the current rate applicable to your specific situation.

Life Expectancy & Annual COLA Rate

These advanced inputs help project the total lifetime value of the increased annuity. Life expectancy determines the number of years you are projected to receive pension payments. The COLA rate estimates the annual inflation adjustment your pension will receive, which increases its value over time. For more on this, see our article on the Social Security COLA.

The calculator performs a comprehensive cost-benefit analysis of the military service buyback decision.

First, it calculates the Base Deposit required by multiplying your Total Military Base Pay by the Deposit Rate (e.g., 3% for FERS).

Second, it determines if any interest is due. It calculates the number of interest-accruing years by subtracting the two-year grace period from your Years Since Military Separation. It then compounds interest annually on the base deposit to find the Accrued Interest.

Third, it sums the Base Deposit and Accrued Interest to arrive at the Total Deposit Due.

Fourth, it calculates the direct benefit: the Annual Annuity Increase. This is found by applying the FERS or CSRS pension formula to your bought-back military years. For FERS, this is typically 1% (or 1.1% if eligible) of your High-3 Salary multiplied by your Years of Military Service.

Finally, the calculator projects the long-term value. It calculates the Lifetime Annuity Increase by summing the annual increase over your expected retirement years, adjusted for COLA. It determines the Break-Even Point—the number of years it takes for the cumulative annuity gains to equal the Total Deposit Due. The Return on Investment (ROI) and a summary score are then calculated based on the lifetime gain versus the initial cost.

The calculations are performed in a sequence to determine the cost, benefit, and return on investment.

Deposit Calculation

Base Deposit = Total Military Base Pay x (Deposit Rate / 100)

Interest Years = max(0, Years Since Separation - 2)

Accrued Interest = Base Deposit x ((1 + Interest Rate / 100) ^ Interest Years - 1)

Total Deposit Due = Base Deposit + Accrued Interest

Annuity Increase Calculation (FERS)

First, the calculator determines the FERS multiplier.

Total Service Years = Civilian Years of Service + Years of Military Service

FERS Multiplier = if (Planned Retirement Age >= 62 and Total Service Years >= 20) then 1.1 else 1.0

Then, it calculates the increase to your annual pension.

Annual Annuity Increase = High-3 Average Salary x (FERS Multiplier / 100) x Years of Military Service

Monthly Annuity Increase = Annual Annuity Increase / 12

Financial Analysis

The break-even point and lifetime gain are projected year by year, including COLA.

Annual Gain (Year Y) = Annual Annuity Increase x (1 + COLA Rate / 100) ^ (Y - 1)

Lifetime Annuity Increase = Sum of Annual Gains from Year 1 to (Life Expectancy - Retirement Age)

Break-Even Years = The first year where the cumulative sum of Annual Gains is >= Total Deposit Due

Return on Investment (ROI) = ((Lifetime Annuity Increase - Total Deposit Due) / Total Deposit Due) x 100

For many federal employees, buying back military time is one of the best financial decisions they can make. It essentially allows you to purchase a guaranteed, inflation-protected government pension stream for a relatively small upfront cost. However, the decision depends on your individual circumstances.

Pros of Buying Back Military Time:

• Increased Lifetime Pension: Every year of service bought back permanently increases your FERS or CSRS annuity. This income is guaranteed by the federal government and typically includes cost-of-living adjustments (COLAs).
• Qualify for Retirement Sooner: The additional service years count toward your minimum retirement age (MRA) and years of service requirements, potentially allowing you to retire earlier.
• Unlock the 1.1% FERS Multiplier: For FERS employees, buying back service could push your total creditable years over the 20-year threshold. If you retire at age 62 or later with 20+ years, your annuity is calculated with a 1.1% multiplier instead of 1.0%, a 10% boost.
• Survivor Benefits: The increased annuity also increases the potential benefit for a surviving spouse.

Cons and Considerations:

• Upfront Cost: You must pay the deposit in a lump sum or through installments before you retire. This can be a significant amount, especially if substantial interest has accrued.
• Opportunity Cost: The money used for the deposit could have been invested elsewhere, for example, in the Thrift Savings Plan (TSP) or an IRA. You must weigh the guaranteed return of the pension against potential market returns.
• You Must Waive Military Retired Pay: You cannot "double-dip." If you are receiving or are eligible for military retired pay, you must waive it to receive FERS/CSRS credit for that service, unless the retired pay was awarded for a service-connected disability or based on reserve service.

For most, if you plan to have a long federal career, the return on investment is exceptionally high. Use the calculator to see your specific numbers.

Making a military service deposit is a multi-step process that you should start as early as possible in your federal career to avoid interest charges.

1. Obtain Your Military Service Records: You will need your DD-214 (Certificate of Release or Discharge from Active Duty) for each period of service.
2. Estimate Your Earnings: Request your estimated military earnings by completing Form RI 20-97, Estimated Earnings During Military Service, and sending it to the appropriate military finance center for your branch of service.
3. Submit Your Application: Once you receive your estimated earnings, complete Form SF 3108 (for FERS) or SF 2803 (for CSRS), Application to Make Deposit or Redeposit. Submit this form, along with your DD-214 and earnings statement, to your agency's human resources or payroll office.
4. Receive Your Calculation: Your agency will calculate the exact amount of your deposit, including any interest owed, and provide you with payment instructions.
5. Make the Deposit: You can typically pay the deposit in a lump sum or arrange for payroll deductions. The deposit must be paid in full before you retire to receive credit for the service.

It is critical to keep copies of all paperwork and proof of payment for your records.

• Total Deposit: This is the full amount you must pay to get credit for your military service. It includes the base deposit plus any interest that has accrued because you are outside the two-year grace period.
• Annual Annuity Increase: This is the most important benefit. It shows how much your yearly pension will increase for the rest of your life. The monthly amount is also shown for budgeting context.
• Break-Even: This is the number of years it will take in retirement for your extra pension payments to "pay back" your total deposit. A shorter break-even period (e.g., under 7 years) is generally very favorable.
• Lifetime Gain: This projects the total additional income you could receive over your entire retirement, factoring in COLAs. It demonstrates the powerful long-term impact of the buyback.
• ROI Score & Insights: The score gives you a quick summary of the financial quality of the decision. An ROI of several hundred percent is common and indicates an excellent investment. The insights panel provides plain-English explanations of what the numbers mean for you.
• Service Credit Summary: This section clarifies how the buyback impacts your total years of service and whether it helps you qualify for the enhanced 1.1% FERS multiplier.

While the core calculation is fixed, you can maximize the value of your decision in several ways:

• Act Early: The single best way to improve your return is to make the deposit within your two-year interest-free grace period. Avoiding years of compounded interest can save you thousands of dollars.
• Maximize Your High-3 Salary: Since the annuity increase is based on your high-3 salary, promotions and pay raises late in your career will increase the value of the years you buy back.
• Aim for the 1.1% Multiplier: If you are a FERS employee, plan your career to work until at least age 62 with 20 or more years of total service (including the buyback). This 10% pension boost significantly enhances the value of every year of service.
• Review Your Retirement Timeline: Use the Retirement Age Calculator to see how working a few extra years could impact your overall financial readiness and the value of your pension.

1. Waiting Too Long: Procrastinating is the most expensive mistake. Interest on the deposit can sometimes exceed the base deposit amount itself, dramatically reducing your ROI.
2. Forgetting to Complete Payment: The deposit must be paid in full before your retirement date. If it's not, you will not receive any credit for your military service.
3. Using Incorrect Earnings: Relying on a guess for your military base pay can lead to an inaccurate estimate. Always request official earnings records for the most precise calculation.
4. Not Waiving Military Retired Pay: If you are eligible for military retirement pay, you must formally waive it to receive FERS/CSRS credit. Failing to do so can cause significant pay and processing issues at retirement.
5. Assuming It Doesn't Apply to You: Many federal employees with military service are unaware of this benefit or assume it's not worth it. Always run the numbers with this calculator to see for yourself.