FERS Disability Retirement 2026: The Two-Formula Math and What You'll Actually Receive

Last Updated: May 20, 2026

If you want to know whether you qualify for FERS disability retirement, read our eligibility post. If you want the application process, read our complete guide. This post is the math.

Specifically, it covers what you will actually receive at three points: the first 12 months, months 13 through age 62, and at the age-62 recomputation. The recomputation is the part most articles get wrong, or skip entirely. For most mid-career federal employees, it produces a pay cut at 62, not an upgrade.

Key Takeaways

• Year 1: 60% of your high-3 average salary, minus 100% of any SSDI benefit you receive.
• Year 2 through age 62: 40% of your high-3, minus only 60% of your SSDI benefit. If you have SSDI, your total income in year 2+ can actually exceed year 1 total income.
• Age 62 recomputation: OPM converts to the regular FERS formula using your actual service years plus all years spent on disability. For most mid-career profiles, this means a lower annuity than the 40% floor, not a higher one.
• OPM processing for disability: 4 to 12 months for most applications. No official government statistic exists for disability-specific timelines.
• Interim payments start after OPM's initial approval at about 80% of estimated final annuity. Budget for a gap of 1 to 4 months with no income before that first check.

The Statutory Two-Formula Structure

FERS disability retirement annuity computation is governed by 5 USC § 8452. It has two formulas that apply at two different points in time, plus an automatic conversion at age 62.

Formula 1: First 12 months of disability retirement

Annual annuity = 60% × high-3 average salary
                 MINUS 100% of any SSDI benefit received

Formula 2: Month 13 through age 62

Annual annuity = 40% × high-3 average salary
                 MINUS 60% of any SSDI benefit received

At age 62: automatic recomputation

OPM switches to the regular FERS formula under 5 USC § 8415:

Annual annuity = 1.0% (or 1.1%) × COLA-adjusted high-3 × total service years

Where "total service years" includes your actual creditable service plus every year you received the disability annuity. The 1.1% multiplier applies if total service at age 62 reaches 20 or more years.

These three formulas are not equivalently generous. The dollar differences matter a lot depending on where you are in the timeline.

Year 1 Annuity: The 60% Phase

For the first 12 months after your disability retirement date, you receive 60% of your high-3 average salary. This is before any SSDI offset.

Your "high-3" is the average of your highest 36 consecutive months of basic pay, including locality pay. It is fixed at the time of your retirement and will not increase during disability retirement (though it gets COLA adjustments for the age-62 recomputation).

Year 1 FERS Disability Annuity by High-3 Salary

High-3 Salary	Year 1 Gross (60%)	Monthly Gross	With $1,800/mo SSDI Offset	Monthly with SSDI
$55,000	$33,000/yr	$2,750/mo	$33,000 - $21,600 = $11,400/yr FERS	$950/mo FERS + $1,800 SSDI = $2,750 total
$75,000	$45,000/yr	$3,750/mo	$45,000 - $21,600 = $23,400/yr FERS	$1,950/mo FERS + $1,800 SSDI = $3,750 total
$100,000	$60,000/yr	$5,000/mo	$60,000 - $21,600 = $38,400/yr FERS	$3,200/mo FERS + $1,800 SSDI = $5,000 total
$130,000	$78,000/yr	$6,500/mo	$78,000 - $21,600 = $56,400/yr FERS	$4,700/mo FERS + $1,800 SSDI = $6,500 total

SSDI example uses $1,800/month ($21,600/year), approximate average for a mid-career federal employee. Actual SSDI amount is based on your Social Security earnings record.

When SSDI is approved, OPM pays a smaller FERS check, but total income (FERS + SSDI combined) stays the same as the no-SSDI figure. The dollar-for-dollar offset in year 1 prevents double-dipping. It does not cut your total pay.

Year 2+ Annuity: The 40% Phase and the SSDI Math Twist

Starting with month 13 of disability retirement, your gross benefit drops from 60% to 40% of your high-3. This is permanent until age 62.

But the SSDI offset changes in your favor: instead of subtracting 100% of SSDI, OPM now subtracts only 60% of SSDI.

Year 2+ FERS Disability Annuity by High-3 Salary

High-3 Salary	Year 2+ Gross (40%)	Monthly Gross	60% SSDI Offset ($1,080/mo = $12,960/yr)	Monthly FERS	FERS + SSDI Total
$55,000	$22,000/yr	$1,833/mo	$22,000 - $12,960 = $9,040/yr	$753/mo	$2,553/mo total
$75,000	$30,000/yr	$2,500/mo	$30,000 - $12,960 = $17,040/yr	$1,420/mo	$3,220/mo total
$100,000	$40,000/yr	$3,333/mo	$40,000 - $12,960 = $27,040/yr	$2,253/mo	$4,053/mo total
$130,000	$52,000/yr	$4,333/mo	$52,000 - $12,960 = $39,040/yr	$3,253/mo	$5,053/mo total

60% of $1,800/mo SSDI = $1,080/mo offset. Remaining $720/mo passes through above the FERS annuity.

At every salary level shown, total income in year 2+ with SSDI ($2,553 to $5,053/mo) beats year 2+ without SSDI ($1,833 to $4,333/mo). The SSDI benefit clears $720/month more than the offset takes. Being approved for SSDI during disability retirement adds income rather than reducing it.

The Age-62 Recomputation: What Actually Happens

This is where most federal employees are surprised, and where the editorial coverage is weakest.

At age 62, OPM stops the 40% formula and recalculates using the regular FERS pension formula. It credits you with both your actual service years AND every year you received the disability annuity. That "service credit" is frequently cited as a benefit.

What is less often stated: for typical mid-career profiles, the recomputed annuity is lower than the 40% floor it replaces.

Model profile for the table below: Disability retirement at age 48, 15 years of actual service. At age 62: 14 years of disability time added, total 29 service years. Multiplier: 1.0% (29 years is less than 20 years for the 1.1% threshold, which requires a minimum of 20 total service years).

Age-62 Recomputation vs. Year 2+ Annuity

High-3 Salary	Age-62 Annuity (29 yrs × 1.0%)	Year 2+ Disability (40%)	Dollar Change at 62
$55,000	$15,950/yr ($1,329/mo)	$22,000/yr ($1,833/mo)	Down $6,050/yr
$75,000	$21,750/yr ($1,813/mo)	$30,000/yr ($2,500/mo)	Down $8,250/yr
$100,000	$29,000/yr ($2,417/mo)	$40,000/yr ($3,333/mo)	Down $11,000/yr
$130,000	$37,700/yr ($3,142/mo)	$52,000/yr ($4,333/mo)	Down $14,300/yr

High-3 held constant for simplicity. Actual OPM computation applies COLAs received during disability years to the high-3, which narrows the gap. But even with 14 years of 2.5% average COLA, the recomputed high-3 would be approximately $76,000 for the $55,000 scenario, producing $22,040/yr, just barely ahead of the $22,000 floor. The COLA adjustment roughly neutralizes the step-down near the $55K level but does not overcome it at higher salary levels.

OPM's rule: if the regular FERS formula at 62 produces a higher figure than the disability formula, OPM uses the higher one. For most profiles it does not. OPM is not hiding this. Most articles just never run the comparison.

When Does the Recomputation Beat the 40% Floor?

To exceed 40% of your high-3 using the regular FERS formula, your total service credit at age 62 must satisfy:

Total service years × multiplier > 40%

At 1.0% multiplier: need 40+ total service years
At 1.1% multiplier: need ~36.4 total service years (rounded to 37)

Break-Even Service Table: When Recomputation Exceeds 40%

Age at Disability Retirement	Max Disability Years Added by 62	Actual Years Needed to Hit Break-Even (1.0%)	Actual Years Needed (1.1%)	Realistic?
40	22	18 actual years needed	15 actual years needed	Possible for GS-13+ career
45	17	23 actual years needed	20 actual years needed	Less common at 45
48	14	26 actual years needed	23 actual years needed	Uncommon at 48
52	10	30 actual years needed	27 actual years needed	Rare at 52

Bottom line: For most disability retirees, the 40% floor is the peak. The age-62 recomputation is most beneficial for employees who retired on disability at a young age (under 43) with substantial actual service. For the average disability retiree (CRS data: average age 50.6, average service 13.2 years), the recomputation at 62 produces a lower annuity.

This does not make FERS disability retirement a bad deal. It means the 40% phase is the primary benefit period, and financial planning should treat it as the income floor, not a bridge to something better.

The OPM Backlog and What It Means for Disability Applications

OPM's overall retirement backlog stood at 49,888 pending cases as of April 2026, the first time it has dropped below 50,000 since November 2025. Average processing time for all retirements is 78 days as of April 2026. More detail in our OPM retirement processing times post.

Disability applications are different.

OPM does not publish separate processing statistics for disability applications. Based on practitioner reporting from federal disability retirement law firms, disability applications currently take 4 to 12 months for an initial determination. The wide range reflects complexity: a complete file with strong medical documentation and a cooperative agency submission moves faster. An incomplete file, a disputed accommodation claim, or a complex SSDI interaction can stretch to a year.

The 2025 surge from the DRP (Deferred Resignation Program) and VERA offers added tens of thousands of applications to OPM's queue. Disability cases require more hands-on review than regular retirements: OPM must verify medical documentation, confirm the agency's accommodation certification, and coordinate SSDI status with Social Security. They share the same examiner pool as the increased regular retirement volume.

Once OPM issues an initial approval, interim payments start at roughly 80% of your estimated final annuity. Most disability retirees see their first interim check 1 to 4 months after OPM receives a complete application. The final, actuarially correct amount may not be settled for 12 to 18 months. OPM makes up the difference retroactively.

The gap between your last federal paycheck and that first interim check is the real planning problem. For disability retirement it commonly runs 3 to 6 months. LWOP (Leave Without Pay) keeps you on the rolls, but does not generate income. Sick leave and annual leave are usually exhausted during the application period. You need a cash buffer, not just a plan.

For context on how OPM calculation errors can compound these timeline issues, see our post on OPM annuity miscalculations.

Calculate Your FERS Disability Annuity

The tables above use representative salary levels. Your actual computation starts with your specific high-3.

Use the free High-3 Calculator to determine your high-3 from your three highest consecutive years of basic pay. Then apply the formula directly:

• Year 1 FERS annuity (annual): High-3 × 0.60, minus your estimated monthly SSDI benefit × 12
• Year 2+ FERS annuity (annual): High-3 × 0.40, minus your estimated monthly SSDI benefit × 0.60 × 12
• Age-62 estimate: Use the FERS Retirement Calculator and enter your actual service years plus projected disability years as total service

For the age-62 calculation, set your high-3 to the COLA-adjusted estimate (approximate by applying 2.5% per year for the number of disability years expected before 62) and enter total service years.

The FERS Retirement Calculator handles the 1.0% vs 1.1% multiplier threshold automatically based on the service years you enter.

Calculate your FERS disability annuity →

Frequently Asked Questions

How do I calculate my FERS disability retirement annuity?

Year 1: multiply your high-3 average salary by 60%, then subtract 100% of any SSDI benefit you receive. Starting month 13: multiply your high-3 by 40%, then subtract 60% of any SSDI benefit. At age 62, OPM switches to the regular FERS formula using your actual service years plus all years spent on disability. For most mid-career employees with 10 to 20 years of service, the age-62 recomputation produces a lower annuity than the 40% floor.

Does SSDI reduce my FERS disability annuity?

Yes, but the offset works differently in each phase. In year 1, OPM subtracts 100% of your SSDI benefit dollar-for-dollar from your FERS annuity. From month 13 onward, OPM subtracts only 60% of your SSDI benefit. The result: if you receive SSDI, your total combined income (FERS plus SSDI) is higher in years 2 and beyond than it was in year 1, because the 60% offset costs less than the full SSDI benefit provides.

What happens to my FERS disability annuity at age 62?

OPM automatically recomputes your benefit using the regular FERS formula: 1% (or 1.1% if total service is 20 or more years) times your COLA-adjusted high-3 times total service years. Total service counts both your actual work years and every year you received the disability annuity. For typical mid-career profiles (15 years of service, retiring at 48), this recomputation produces about 29% of high-3, which is lower than the 40% floor it replaces.

How long does OPM take to process a FERS disability retirement application in 2026?

OPM does not publish separate processing timelines for disability applications. For all retirements, April 2026 average processing was 78 days. Disability cases require medical documentation review, agency certification verification, and SSDI coordination, so they take longer. Federal disability retirement attorneys report most disability applications currently take 4 to 12 months for an initial determination. Plan your finances for at least a 6-month income gap before receiving a final annuity payment.

When does the age-62 recomputation produce a higher annuity than the 40% floor?

When your total service credit at age 62 (actual years plus disability years) times the 1% or 1.1% multiplier exceeds 40%. At the 1.0% multiplier, you need 40 total service years at 62. At the 1.1% multiplier (20 or more total years), you need roughly 37 total years. This is achievable if you retired on disability at a young age with substantial service. Retiring at 42 with 20 years of service gives you 20 actual plus 20 disability years at age 62, clearing the break-even at the 1.1% rate.

Can I get interim payments while OPM processes my disability application?

Yes. Once OPM issues an initial approval, interim payments begin at approximately 80% of your estimated final annuity. Plan for 1 to 4 months between your last federal paycheck and the first interim payment. The final annuity amount may not be settled for 12 to 18 months, with OPM reconciling the difference retroactively.

A Note on This Post

This post covers the computation mechanics of FERS disability retirement. It is not legal, medical, or financial advice. Your specific benefit depends on your OPM records, your SSDI determination, and your agency's certification. If you believe OPM has calculated your annuity incorrectly, you have 30 calendar days from OPM's initial written decision to file a reconsideration request.

Related Resources

• FERS Disability Retirement Eligibility 2026: Whether you qualify and the 8 traps that kill eligible claims
• FERS Disability Retirement Guide 2026: The application process, forms, and what to expect
• OPM Retirement Processing Times 2026: Current backlog data and timeline
• OPM Annuity Miscalculation: Verify Your FERS Calculation: How to catch OPM errors before they cost you
• FERS Retirement Calculator: Model your age-62 recomputation scenario
• High-3 Calculator: Calculate your high-3 average salary

Sources: 5 USC § 8452 (Disability Annuity Computation) · 5 USC § 8415 (Basic Annuity) · OPM RI 83-12: FERS Disability Retirement Pamphlet · OPM Types of Retirement · 5 CFR Part 844 · CRS Report 98-972 (FY2022 Disability Retirement Data) · OPM Monthly Processing Information