OPM retirement calculator 2026: the computation OPM runs on your FERS file
This site is not OPM. The calculator below reproduces, as an independent estimate, the steps OPM Retirement Services follows when it turns your records into a monthly FERS annuity.
Immediate unreduced annuity, from age 60
$1,765/mo
$21,180 a year, plus $935/mo of supplement until 62.
| Basic annuity (22 years, 9 months counted) | $22,295 |
| Survivor benefit cost | -$1,115 |
| FERS supplement until 62 | $935/mo |
| Your MRA | 56 and 4 months |
| Survivor would receive | $464/mo |
Age 60 with 20 years · 1 %.
Prepared by Radif Partners · How the figures are built · read on opm.gov, ecfr.gov and ssa.gov · not an official determination
OPM Retirement Services computes a FERS annuity in a fixed order. It totals your creditable service and drops any fraction of a month, adds unused sick leave for the computation, multiplies your high-3 by 1 % per year (1.1 % at 62 with 20 years), applies the age reduction of an MRA+10 or early deferred annuity, then the survivor reduction, and divides by 12, rounding down to the dollar. An employee born in 1966 who leaves at 60 with 22 years and 4 months, a $98,000 high-3 and 900 hours of sick leave is credited with 22 years and 9 months: $22,295 a year. The partial survivor benefit costs 5 %, leaving $1,765 a month. While OPM finishes the file, which takes about 3 to 5 months in all, it pays interim payments of typically 60 % to 80 % of the estimated net annuity, then an adjustment payment once the final computation is done. This page and its calculator are an independent estimate, not an OPM tool.
An independent estimate, not an OPM tool
People search for an OPM retirement calculator because OPM is the office that pays the annuity. This site is run by an independent publisher; it has no link with the Office of Personnel Management and no access to your records. What it can do is follow the published computation rules, those of OPM's FERS computation page and of chapter 50 of the CSRS and FERS Handbook, in the same order OPM applies them, so that the gap between your estimate and the first OPM letter is as small as possible. The general calculator, with every retirement type explained, is on the FERS retirement calculator page.
Step 1: total creditable service
OPM adds all periods of creditable service in years, months and days, then eliminates any fractional part of a month. Under FERS, the service that gives the right to retire is the same service used in the computation and in the high-3 period. Military service is added only if the deposit was paid in full before retirement. Unused sick leave is converted with a chart in which 2,087 hours equal one year, and the result is added to service for the computation of an immediate annuity, not for eligibility. In the case on this page, 900 hours add 5 months to 22 years and 4 months, for 22 years and 9 months in all.
Step 2: the high-3 average
The high-3 is the highest average basic pay over any three consecutive years of service. OPM's worksheets weight each rate of pay by the time it was in force, and the handbook rounds the average to the nearest dollar. Overtime and bonuses are left out. Your payroll office certifies the pay history; OPM does not rebuild it from your SF-50s, which is one reason why a missing pay record holds up the file.
Step 3: the accrual factor
OPM reads a factor from a chart: the service in years and months times 1 %, or times 1.1 % for those who separate at 62 or later with 20 years. For special-provision employees the first 20 years count at 1.7 %. Multiplying the high-3 by the factor gives the unreduced basic annuity: $98,000 times 22 years and 9 months at 1 % gives $22,295 a year.
Change the service months and the sick leave
Immediate unreduced annuity, from age 60
$1,765/mo
| Basic annuity (22 years, 9 months counted) | $22,295 |
| Survivor benefit cost | -$1,115 |
| FERS supplement until 62 | $935/mo |
| Your MRA | 56 and 4 months |
Step 4: reductions, in a set order
The handbook lists the reductions and the order in which they apply. The age reduction comes first, for an MRA+10 or early deferred annuity: five twelfths of 1 % for each full month under 62 on the commencing date, waived if the annuity starts at 60 or later with 20 years. The survivor reduction comes second, computed on the annuity already reduced for age. An alternative annuity reduction, rare, comes last. The order matters because the survivor cost is a percentage of what is left after the age cut.
Take an employee born in 1968 who leaves at the MRA of 56 and 8 months with 16 years and a $90,000 high-3, and starts the annuity at once with the full survivor benefit. The unreduced annuity is $14,400. The age reduction is 26.7 %, so the annuity falls to $10,560. The survivor cost is 10 % of that reduced amount, $1,056, and the retiree keeps $9,504 a year, $792 a month. Following the handbook worksheets, the survivor annuity is 50 % of the base the retiree chose, here the reduced annuity: about $440 a month. The MRA+10 page shows how postponing changes these numbers.
Step 5: the monthly amount
Last, OPM divides the annual figure by 12 and rounds down to the next lower dollar. In the first case, $22,295 less the partial survivor cost of $1,115 is $21,180.25 a year, so $1,765 a month. The partial survivor annuity is 25 % of the annuity: $464 a month. Health and life insurance premiums and tax withholding come off that gross monthly amount later. The FERS supplement, if you qualify, is computed separately and paid alongside; the supplement page covers it.
| Step | What OPM uses | Case 1 |
|---|---|---|
| Service | Years and months, days dropped, sick leave added | 22 years, 9 months |
| High-3 | Basic pay with locality, 3 consecutive years | $98,000 |
| Factor | 1 % a year (1.1 % at 62 with 20 years) | 1 % |
| Basic annuity | High-3 x service x factor | $22,295 |
| Age reduction | MRA+10 and early deferred only | None (60 with 20 years) |
| Survivor reduction | 10 % full, 5 % partial, after the age cut | -$1,115 |
| Monthly | Annual / 12, rounded down | $1,765 |
What Retirement Services needs from you
OPM's Retirement Quick Guide asks you to pay any open service credit or deposit before you leave, to include the documents your application requires, such as marriage, military or court records, and to review your health, life and survivor elections, since they change the annuity. It also suggests downloading your personnel records, because access ends at retirement. Processing cannot start before your separation date.
From your agency to the final computation
Your agency prepares the retirement package and sends it to its payroll office, which pays your last salary and the lump sum for unused annual leave, certifies your records and sends them to OPM, in about 30 to 45 days. OPM then logs the case within 10 to 15 days and assigns your retirement claim number, also called the CSA number. If you are eligible, interim payments begin, typically 60 % to 80 % of your estimated net annuity, with only federal tax withheld and no insurance premiums. The full computation takes another 10 to 90 days. When it is done, OPM pays an adjustment for the difference between the interim and final amounts, deducts the premiums owed since retirement and sends a retirement booklet. Regular payments arrive on the first business day of each month and cover the month before. A budget built on the interim amount for the first months, and on this estimate after that, avoids surprises.
Why your estimate and OPM's figure can still differ
The rules are public, but the inputs are in your file. A period of service without retirement deductions, a refund you took years ago, a deposit left unpaid, a part-time schedule or a court order dividing the annuity all change the result in ways no outside calculator can see. Our method page lists what the estimate assumes. When the official letter arrives, compare it line by line with the table above.