Why some years are worth more
- Every year adds a year of service: 2.5% × your monthly average. Handbook p. 46, Benefit Formula Components; p. 47, Benefit Formula
- Leaving 25-and-Out. Each year raises the 25-and-Out factor, and reaching the Rule of 80 or 30 years removes it. Handbook p. 48, 25-and-Out Factors; RSMo 169.070.1(3)-(7)
- Reaching 32 years lifts the factor to 2.55% on all your years. Handbook p. 47, Normal Retirement Benefits, Eligibility; p. 9, Retirement Eligibility
Example 1: starting at 50 with 25 years
A $4,590 monthly average that stays the same. Our examples, using the handbook's rules.
| Retire at | Service | Kind | Monthly | Added |
|---|---|---|---|---|
| 50 | 25 years | 25-and-Out | $2,524.50 | — |
| 51 | 26 years | 25-and-Out | $2,685.15 | +$160.65 |
| 52 | 27 years | 25-and-Out | $2,850.39 | +$165.24 |
| 53 | 28 years | Normal | $3,213.00 | +$362.61 |
At 53 with 28 years, age plus service is 81: the Rule of 80. That last year adds $362.61 a month.
Example 2: starting at 60 with 28 years
| Retire at | Service | Kind | Monthly | Added |
|---|---|---|---|---|
| 60 | 28 years | Normal | $3,213.00 | — |
| 61 | 29 years | Normal | $3,327.75 | +$114.75 |
| 62 | 30 years | Normal | $3,442.50 | +$114.75 |
| 63 | 31 years | Normal | $3,557.25 | +$114.75 |
| 64 | 32 years | Normal, 2.55% | $3,745.44 | +$188.19 |
The year from 31 to 32 years adds $188.19, because the 2.55% factor applies to every year.
Raises would add more. A year of work also means a year less of benefit checks; whether that trade is worth it is your call.
PSRS counts service by school year, based on salary. The calculator assumes you earn 1 year for every 12 months you keep working.
What we use: 1 year of service per 12 months from today. Your annual Member Statement shows PSRS's own projected dates.
What the handbook says
- Each extra year adds 2.5% of your Final Average Salary to your monthly benefit. In PSRS's example, a 29th year raises $3,213 to $3,328.Handbook p. 33, Purchase Cost Recovery Time (Example)
- Reaching 32 years raises your factor to 2.55% on all your years.Handbook p. 47, Normal Retirement Benefits
- If you're under 55 on 25-and-Out, each extra year raises your factor by 0.05% until you reach the Rule of 80 or 30 years and the full 2.5%.Handbook p. 48, 25-and-Out Factors
- Working three years past full retirement eligibility makes you eligible for the Partial Lump Sum Option.Handbook p. 9, Retirement Eligibility; PLSO brochure p. 2
Questions
How much does one more year add?
At least 2.5% of your final average salary a month, for life. With a $4,590 monthly average that's about $114.75 a month, before any raise.
When is one more year worth the most?
When it moves you from early to normal retirement, or takes you to 32 years and the 2.55% factor.
Source: PSRS Member Handbook, 2026-2027 (as of September 2026), pp. 9, 25, 33, 46, 47, 48; PLSO brochure p. 2; RSMo 169.070. Last reviewed .