You made the decision. You want to buy back your active-duty time so it counts toward your federal pension. Good call for a lot of veterans. But now you're staring at a pile of form numbers. RI 20-97. SF-3108. SF-2803. OPM Form 1515. Nobody handed you a checklist, and your agency HR office assumes you already know the drill.

You don't need to know all of it. You need to know the order. The buyback runs in four steps, and each step has one job. Get the estimate. Take it to HR. File the deposit form. Pay it off before you leave.

This guide walks you through each step in plain English. It names every form and tells you where it goes. By the end you'll know exactly how to start a military buyback, what to gather first, and the one deadline you cannot miss. I'm a Navy Diver who went federal after the service, so I've stood at that HR counter with the same questions.

What Is a Military Buyback, in One Minute?

A military buyback lets you pay a deposit so your active-duty years count toward your federal civilian retirement. Under FERS, that deposit is 3% of the basic pay you earned on active duty, plus interest. It's basic pay only. Not BAH. Not BAS. Not special or incentive pay.

Once the deposit is paid, those years get added to your creditable service. More creditable years means a bigger pension when you retire from the federal side. For anyone who plans to spend a full career in government, it pays for itself many times over.

This article is about the process, not the math or the pension itself. If you want the full breakdown of how the pension grows, read our guide on how the buyback works for retirees. This one gets you moving on the paperwork.

Should You Check One Thing First?

Yes. Before you touch a single form, answer one question. Are you drawing, or will you draw, a military retirement pension?

If you served 20+ years and get monthly retired pay, the buyback usually forces a trade. To count that time toward FERS, you generally have to waive your military retired pay. For most 20-year active-duty retirees, that's a bad deal. Two groups keep both, including reserve retirees paid under Chapter 1223 and some combat-related disability retirees.

If that's you, stop and read our piece on whether to waive military retired pay for FERS before you start. If you didn't retire from the military and you're not drawing a pension, the buyback is almost always a clear win. Keep reading.

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Step 1: Request Your Estimated Earnings (RI 20-97)

The first thing HR needs is a number. They need to know how much basic pay you earned during your active-duty service. You don't guess it. You request an official statement.

The form for this is RI 20-97, Estimated Earnings During Military Service. You fill it out and send it to your military branch's finance center. For most branches that's DFAS. Coast Guard veterans send it to the Coast Guard Pay and Personnel Center instead.

Attach a copy of your DD-214 to the request. Here the DD-214 is doing its real job. It proves your service dates and discharge. This is federal paperwork, not resume material.

The finance center mails back a statement of your estimated basic pay for your active-duty years. This can take a few weeks, so this is the step to start first. Everything after it waits on this letter.

Step 2: Take It to Your Agency HR

When the estimated earnings statement arrives, you don't sit on it. You bring it to your agency's HR or payroll office. That's the office that runs the deposit for you.

Bring three things. The estimated earnings statement from Step 1. A copy of your DD-214. And a request to start a military service deposit. Some agencies have their own intake form. Others just take the documents and open the case.

Your payroll office then figures the deposit. Behind the scenes your payroll office also uses OPM Form 1515 as part of processing your military deposit. It ties your estimated earnings to the amount you owe and the payments you make. Your payroll office drives that part of the process.

Ask HR two questions while you're there. What will my total deposit be, including interest to date? And how do you want me to pay it? The answers set up Step 3.

Step 3: File the Deposit Application (SF-3108 or SF-2803)

Now you make it official. You file the application that says you want to make the deposit. Which form you use depends on your retirement system.

Almost every veteran hired in the last few decades is under FERS. Your form is SF-3108, Application to Make Service Credit Payment. If you're one of the few still under the older CSRS system, your form is SF-2803, Application to Make Deposit or Redeposit. Your HR office will tell you which system covers you if you're not sure.

You sign the application and hand it back to payroll. They confirm the amount and set up your payment. You usually get options. A lump sum. Regular payroll deductions. Or a mix, where you pay some now and chip at the rest each pay period.

Step 4: Pay It Off Before You Separate

This is the step that trips people up. The deposit is not something you settle later with OPM. You pay it to your employing agency while you still work there. It has to be paid in full before you leave federal service, whether you retire or separate.

Miss that window and the years don't count. There's no catching up after you walk out the door. So the real deadline isn't a date on a calendar. It's your last day on the job.

Then there's the interest clock, and it's why starting early matters. You generally get about a two-year interest-free window from the date you're first hired into a FERS-covered job. After that, interest gets added and compounds every year. The rate is set by the government and changes yearly. Wait ten years and you could owe far more than the base 3%.

This is spelled out in the federal statute on FERS deductions and deposits, and OPM lays out the mechanics on its creditable service pages. The takeaway is simple. Start the deposit in your first couple of years and you keep the cost low.

Lump Sum or Payroll Deductions?

Once payroll gives you the amount, you pick how to pay. Both options finish the same deposit. They just spread the cost differently.

A lump sum ends it fast. You write one check or set up one payment, the case closes, and you never think about interest again. This makes sense if the deposit is small or you have the cash on hand. Many FERS deposits are only a few thousand dollars, so a lump sum is doable for a lot of people.

Payroll deductions spread it over time. You pick an amount to come out each pay period until the balance hits zero. This is easier on your budget, but the balance keeps accruing interest until it's fully paid. So a longer payment plan costs a little more overall.

There's no wrong answer. If the number is small and you can swing it, pay the lump sum and be done. If it's larger, deductions keep it painless. Either way, get it started so the interest clock stops growing on new years of delay.

How Long Does a Buyback Take?

The buyback isn't fast, and that's the argument for starting now instead of "someday." Each step has its own wait.

The estimated earnings request is the slowest part. Once you mail RI 20-97 to the finance center, it can take several weeks, sometimes a couple of months, to get the statement back. That clock runs whether you're paying attention or not, so send it early.

Once you hand everything to HR, the deposit calculation is usually quicker. Payroll runs the numbers and comes back with your total and your payment options. From there, the deposit itself takes as long as your payment plan. A lump sum closes it right away. Deductions can run a year or several, depending on the balance and how much you pull each check.

What Does This Look Like When It Works?

Picture your retirement estimate a few years from now. You pull it up and the creditable service line includes your active-duty years. Four years in the Army. Six in the Navy. Whatever you served, it's sitting right there next to your civilian time.

That's the whole point. A veteran with eight bought-back years retires with eight more years of pension credit than the guy who never filed the forms. Same career length on the civilian side. A much bigger monthly check for life.

The cost was a deposit you paid off in your first few years, mostly through small payroll deductions you barely noticed. The payoff shows up every month for the rest of your retirement. That's why so many veterans call it the best paperwork they ever filed.

Start Your Federal Package the Same Way

The buyback works because you attack it in order and knock out one form at a time. Your federal job search works the same way. The paperwork feels like a wall until you break it into steps.

If you're still landing that federal role, the resume is the front door. Federal resumes run two pages and carry more detail than civilian ones, and small format mistakes sink you in the ranking. Our Federal Resume Builder handles the OPM format and the military-to-civilian translation for you. It's free to start, built by veterans who've been through the federal process.

Already have the job and just want to lock in your years? Go request that RI 20-97 today. And if you came into federal service late, our guide on going federal years after separation covers what else changes when you start later. Either way, the sooner you start, the less that interest clock costs you.