Missouri MOSERS Retirement Calculator
Estimate your Missouri State Employees' Retirement System pension. Pick MSEP, MSEP 2000 or MSEP 2011, enter your service and final average pay, and see your base benefit, any temporary benefit to 62, the early reduction if you go sooner, and a COLA illustration.
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Three plans, set by when you started
The rules here come from MOSERS's General Employees' Retirement Handbook (February 2026) and its Summary of Plan Benefits. They cover general state employees.
- MSEP: first employed in a benefit-eligible position before July 1, 2000, and vested. 1.6% multiplier. No employee contributions.
- MSEP 2000: first employed July 1, 2000 through December 31, 2010. 1.7%. No employee contributions.
- MSEP 2011: first employed on or after January 1, 2011. 1.7%. You contribute 4% of pay.
Monthly Base Benefit = Multiplier x Final Average Pay x Credited Service
Final average pay is your highest 36 consecutive months. The handbook's example: $3,000 a month and 33 years pays $1,584 in MSEP and $1,683 in MSEP 2000 or MSEP 2011.
When you can retire unreduced
- MSEP: 65 with 5 years, 60 with 15 years, or the Rule of 80 from age 48.
- MSEP 2000: 62 with 5 years, or the Rule of 80 from age 48.
- MSEP 2011: 67 with 5 years, or the Rule of 90 from age 55.
The rules count your age plus service when you leave state employment. If you were first eligible before August 28, 2003, the Rule of 80 minimum age is 50 instead of 48.
The temporary benefit
Retire under the Rule of 80 in MSEP 2000, or the Rule of 90 in MSEP 2011, and MOSERS adds a temporary benefit of 0.8% x final average pay x service until you turn 62. In the handbook's example, that's $792 a month on top of the $1,683 base, $2,475 in all. At 62 the temporary benefit and any COLAs earned on it stop, and you're left with the base. MSEP doesn't have one.
Early retirement
MSEP members can retire early at 55 with 10 years, MSEP 2000 members at 57 with 5, and MSEP 2011 members at 62 with 5. The base benefit drops 0.5% for every month you're younger than normal retirement age, 6% a year. Thirty months early leaves 85% of the base. An MSEP 2011 member leaving at 62 with 10 years is 5 years short of 67, so the cut is 30%.
If you leave vested (5 years) before you can retire, your benefit waits until normal retirement age.
BackDROP
MSEP and MSEP 2000 members who work at least two years past their first normal retirement date can elect BackDROP. Your monthly pension is figured as if you'd retired on an earlier BackDROP date, up to five years back, and you also get a lump sum equal to 90% of the Life Income Annuity payments you'd have received during that period. The monthly check is usually smaller. MSEP 2011 doesn't offer BackDROP.
The COLA
Each year's COLA is 80% of the increase in the average CPI, with a floor of 0% and a cap of 5%. A 2.5% CPI increase means a 2% COLA. MOSERS's handbook examples use 1.5%.
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Frequently asked questions
How is a MOSERS pension calculated?
Multiplier x final average pay x credited service. The multiplier is 1.6% in MSEP and 1.7% in MSEP 2000 and MSEP 2011. Final average pay is your highest 36 consecutive months. MOSERS's example: $3,000 a month x 33 years is $1,584 a month in MSEP and $1,683 in MSEP 2000.
Which MOSERS plan am I in?
MSEP if you were first employed in a benefit-eligible position before July 1, 2000 and vested in MSEP. MSEP 2000 if you were first employed from July 1, 2000 through December 31, 2010. MSEP 2011 if you were first employed on or after January 1, 2011.
What are the Rule of 80 and Rule of 90?
In MSEP and MSEP 2000 you can retire unreduced once your age plus service reaches 80, as long as you're at least 48 (50 if you were first eligible before August 28, 2003). In MSEP 2011 it's the Rule of 90, from age 55. Otherwise normal retirement is 65 with 5 years or 60 with 15 (MSEP), 62 with 5 (MSEP 2000), or 67 with 5 (MSEP 2011).
What is the temporary benefit?
MSEP 2000 members retiring under the Rule of 80 and MSEP 2011 members retiring under the Rule of 90 get an extra 0.8% x final average pay x service each month until 62. In MOSERS's example that's $792 a month on top of a $1,683 base. The temporary benefit and any COLAs on it stop at 62. MSEP has no temporary benefit.
Does MOSERS have a COLA?
Yes. It's 80% of the increase in the average CPI, between 0% and 5% a year. MSEP members employed before August 28, 1997 had a different schedule until reaching a 65% cap.