USERRA Military Buyback: The Lesser-Of Calculation for Returning Federal Employees

When USERRA Changes the Deposit Math

Most federal employees pay 3% of their military basic pay (FERS) or 7% (CSRS) to buy back active-duty time. But if your military service directly interrupted a period of federal civilian employment — you left your desk, deployed, and returned to the same position afterward — the Uniformed Services Employment and Reemployment Rights Act creates a different calculation.

Under 5 CFR § 842.307 for FERS and § 831.2104 for CSRS, the deposit for USERRA-covered service is the lesser of two amounts:

1. The standard military deposit — 3% (FERS) or 7% (CSRS) of your military basic pay during the interruption
2. The civilian retirement deductions that would have been withheld from your civilian salary had you never left

For many employees, option 2 is substantially cheaper. Standard FERS retirement contributions are 0.8% of civilian pay for employees hired before 2013, 3.1% for FERS-RAE (hired 2013), and 4.4% for FERS-FRAE (hired 2014+). Even at the FRAE rate, 4.4% of civilian pay is often less than 3% of military basic pay — especially for junior enlisted service members whose military base pay was lower than their civilian GS salary.

How the Calculation Works

Suppose a GS-11 earning $75,000 annually left federal service for a 12-month deployment. During deployment, their military basic pay averaged $3,500/month ($42,000 annually).

Standard military deposit (3% of military pay): $42,000 × 3% = $1,260

USERRA lesser-of (civilian deductions that would have been withheld):

• Pre-2013 FERS (0.8%): $75,000 × 0.8% = $600
• FERS-RAE (3.1%): $75,000 × 3.1% = $2,325
• FERS-FRAE (4.4%): $75,000 × 4.4% = $3,300

For the pre-2013 FERS employee, the USERRA lesser-of calculation cuts the deposit in half — $600 versus $1,260. For a FERS-FRAE employee, the standard military deposit is actually cheaper, so that's what applies.

The Problem: Agencies Getting It Wrong

The USERRA lesser-of rule is one of the most frequently misapplied provisions in the military buyback process. Many agency HR specialists default to the standard 3% or 7% calculation for all military deposits, regardless of whether the service interrupted civilian employment.

This isn't malicious — it's a matter of awareness. The lesser-of rule exists in OPM Benefits Administration Letters and the CFR, but it doesn't appear on the face of the SF 3108 or SF 2803 forms. If you don't flag it, your specialist may not apply it.

When you submit your deposit paperwork, include a cover memo citing 5 CFR § 842.307(b)(2) for FERS or § 831.2104 for CSRS. State that your military service interrupted civilian federal employment under USERRA and request the lesser-of calculation. Attach documentation of your civilian salary during the period immediately before your military departure.

Qualifying for USERRA Protection

Not all military service qualifies. The lesser-of rule applies specifically when:

• You held a civilian federal position immediately before the military service
• You returned to federal civilian employment under USERRA reemployment rights
• The military service was one of the types covered by USERRA (active duty, active duty for training, initial active duty for training, inactive duty training, fitness examinations, or funeral honors duty)

If you separated from federal service voluntarily, served in the military, and then later applied for a new federal job — rather than returning under USERRA reemployment rights — the standard deposit rates apply. The lesser-of calculation is specifically tied to interrupted service with reemployment, not sequential careers.

Interest on USERRA Deposits

USERRA-qualifying deposits follow the same interest rules as standard deposits. If you're past the three-year grace period from your first date of retirement-covered service, interest accrues annually on the unpaid balance at Treasury rates.

However, the interest accrues on the lesser-of amount, not the standard amount. A lower base deposit means lower accumulated interest, which further widens the savings over time.

Getting the Correction If You've Already Overpaid

If your agency applied the standard 3% rate when the USERRA lesser-of should have applied, you may be entitled to a correction. Contact your HR benefits specialist with the CFR citation and documentation of your USERRA reemployment. The payroll office can recalculate the deposit and issue a refund of the overpayment.

The Military Buyback Guide includes a USERRA lesser-of worksheet that walks through both calculations side by side, along with the exact regulatory citations and sample cover language to ensure your agency applies the correct rate.

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