CSRS Basic Annuity Calculation
for Regular Employees

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The basic CSRS annuity is expressed as a percentage of your high-3 average salary. 

Your high 3 percentage is determined by a three-part formula based on your length of creditable service. You earn:

  • 1.5% x High-3 x first five years of service
  • plus 1.75% x High-3 x next five years of service
  • plus 2.0% x High-3 x all years of service over 10

Thus, after 10 years of service you have earned 16.25% of your "high three" and after 30 years you have earned 56.25% (16.25% + 2% x 20 = 56.25%). 

By law, the percentage is limited to 80% (reached after 41 years and 11 months of service)however, unused sick leave can be used in the formula to produce a greater result.

Your unused sick leave is converted into months and days and added to your other service. Credit is given for whole months only, (30 days). However, the time representing days of unused sick leave is not counted toward your "high 3" years average salary or for establishing eligibility for retirement.

Example 1:
Age 55
High-3 $60,000
Years of Service 30 years

.015 x 5 x $60,000

= $4,500

.0175 x 5 x $60,000

= $5.250

.02 x 20 x $60,000

= $24,000
   $33,750  (56.25% of High-3)
Example 2:
Age 60
High-3 $50,000
Years of Service 20 years

.015 x 5 x $50,000

= $3,750

.0175 x 5 x $50,000

= $4,375

.02 x 10 x $50,000

= $10,000
   $18,125  (36.25% of High-3)

Source: OPM RI 83-7