- Your yearly benefit is your average salary times your multiplier, minus any early-retirement reduction.Member Handbook (2025), p. 41, Calculating Benefits for Regular Members
- The multiplier grows 2% for each year of service up to 30 years, which makes 60%. It then grows 1% a year for years 31 to 35, up to 65%. Service counts by the quarter, and nothing past 35 years is used.Member Handbook (2025), p. 42, Multiplier and Regular Member Multiplier table; p. 40, sidebar
- IPERS's sample estimate: David is 67 with 32 years and an average salary of $90,213.63. His multiplier is 62%, so his Option 2 benefit is about $4,661.04 a month.IPERS Overview slides (2025), slides 17-19, David's Sample Retirement Estimate
- If you have at least 10 years of service, your benefit is at least $50 a month under Option 2 at normal retirement age. If your Option 2 benefit would be under $50 a month, IPERS pays a lump sum instead.Member Handbook (2025), p. 41, Minimum Benefit; Mandatory Lump-Sum Payment
The multiplier table
2% a year to 30 years, then 1% a year. With the monthly amount on a $60,000 average salary, at normal retirement age.
| Years | Multiplier | A month |
|---|---|---|
| 7 | 14% | $700 |
| 8 | 16% | $800 |
| 9 | 18% | $900 |
| 10 | 20% | $1,000 |
| 11 | 22% | $1,100 |
| 12 | 24% | $1,200 |
| 13 | 26% | $1,300 |
| 14 | 28% | $1,400 |
| 15 | 30% | $1,500 |
| 16 | 32% | $1,600 |
| 17 | 34% | $1,700 |
| 18 | 36% | $1,800 |
| 19 | 38% | $1,900 |
| 20 | 40% | $2,000 |
| 21 | 42% | $2,100 |
| 22 | 44% | $2,200 |
| 23 | 46% | $2,300 |
| 24 | 48% | $2,400 |
| 25 | 50% | $2,500 |
| 26 | 52% | $2,600 |
| 27 | 54% | $2,700 |
| 28 | 56% | $2,800 |
| 29 | 58% | $2,900 |
| 30 | 60% | $3,000 |
| 31 | 61% | $3,050 |
| 32 | 62% | $3,100 |
| 33 | 63% | $3,150 |
| 34 | 64% | $3,200 |
| 35+ | 65% | $3,250 |
How Iowa law writes it
Monthly benefit = 1/12 x applicable percentage x final average covered wage x fraction of years of service (service / 30, not over 1). Applicable percentage = 60%, plus 0.25 percentage point per calendar quarter beyond 30 years, up to 5 points. Iowa Code §97B.49A(1), (3); Iowa Admin. Code r. 495—12.1(4)(a), (c)
It's the same as the table: 60% for 30 years, and 0.25 of a point for each quarter beyond. No more than 35 years (140 quarters) are used; the multiplier does not increase beyond 35 years. Member Handbook (2025), p. 40, sidebar (maximum number of quarters used to calculate your benefit)
IPERS's example: David
David is 67 with 32 years. His multiplier is 62%.
IPERS's sample estimate shows $4,661.04. IPERS Overview slides (2025), slides 17-19 and 21-27, David's Sample Retirement Estimate
Your average salary: high five or high three?
- Your average salary is built from calendar-year covered wages. If you start benefits after June 2012, it is the higher of two figures: your highest three-year average as of June 30, 2012, and your highest five-year average over your whole career. The years don't have to be consecutive.Member Handbook (2025), p. 41, Average Salary; IPERS web page Regular Members' Retirement Benefit Calculation
- Check with IPERSIowa law gives the June 30, 2012 three-year figure only to members who were vested on that date. IPERS's web page just says the average of your highest five years.The handbook does not mention the vesting condition.Iowa Code §97B.1A(10A); IPERS web page Regular Members' Retirement Benefit Calculation
- IPERS checks your average for wage spiking. Your five-year average can't be more than 134% of your highest year outside those five. The three-year figure can't be more than 121% of your highest year outside those three.Member Handbook (2025), p. 42
- If you leave partway through a year, IPERS can fill in the missing quarters to build a full final year. That computed year is capped at 103% of your highest calendar year, and it gives you no extra service.Member Handbook (2025), p. 42
David's average is his highest 5 calendar years:
| Year | Covered wages |
|---|---|
| 2024 | $86,676.53 |
| 2025 | $88,410.06 |
| 2026 | $90,178.26 |
| 2027 | $91,981.83 |
| 2028 | $93,821.46 |
| Average of 5 | $90,213.63 |
The handbook says everyone starting benefits after June 2012 gets the higher of their June 30, 2012 high-three average and their high-five. Iowa law and IPERS's rules give the high-three only to members vested on June 30, 2012.
The calculator uses the average salary you enter. Our guides describe the handbook's rule and point out the difference.
What would settle it: IPERS confirmation.
The wage-spiking test
IPERS compares the high-five (high-three) average to a control-year salary: the highest calendar year outside the five (three) years in the average. If the average is more than 134% (121%) of the control year, the salary in the formula is cut to 134% (121%) of the control year. Member Handbook (2025), pp. 41-42, Average Salary
IPERS's example of the three-year test (for a Protection Occupations member, the same 121% rule): a $60,000 average against a $46,000 control year is cut to $55,660, which is 121% of $46,000. Member Handbook (2025), p. 45, Example 2: Retirement Benefits Calculated With Control-Year Salary
Leaving partway through a year
If you stop working before the end of a calendar year, IPERS fills the missing quarters with the average quarter of your highest calendar year not used in the average (the computed-year wage). It is used if higher than your fifth- (or third-) highest year, but is limited to 103% of your highest calendar year wage and earns no extra service. Member Handbook (2025), pp. 41-42, Average Salary
The minimum benefit
A member retiring on or after July 1, 1990 with at least 10 years of service gets at least $50 a month, under Option 2 at normal retirement age (reduced if earlier or under another option). If the Option 2 benefit would be under $50 a month, IPERS pays a lump sum equal to the member's and employer's accumulated contributions. Member Handbook (2025), p. 41, Minimum Benefit; Mandatory Lump-Sum Payment; p. 40, Actuarial Equivalent Lump-Sum Benefit Payment
If you started before 1976
- Members employed before Jan. 1, 1976 (or vested before then with 4+ years) get the larger of the standard formula and 1.57% x years of membership service x average annual covered wage; members with pre-July 4, 1953 prior service have a further alternative. Iowa Code §97B.49A(4)(a)-(b)
- Members retiring July 1, 1986 - June 30, 1994 used a lower applicable percentage (50% rising to 57.4%) of the three-year average covered wage; 60% applies from July 1, 1994. Iowa Code §97B.49G(1)
- Members who retired July 1, 1988 - Dec. 31, 1998 could have unreduced benefits under a Rule of 92 or 90, or at 62 with 30 years. Iowa Code §97B.49G(4)
Try your own numbers in the calculator, or see the Rule of 88 and early retirement.
Common questions
What is the IPERS multiplier?
2% for each year of service up to 30 years, which makes 60%, then 1% a year for years 31 to 35, up to 65%. Service counts by the quarter.
Is IPERS's average salary the high three or the high five?
For benefits starting after June 2012, the handbook says the higher of your highest 3 calendar years as of June 30, 2012 and your highest 5 years over your career. Iowa law limits the three-year figure to members vested on June 30, 2012.
Source: IPERS Member Handbook, Updated July 2025, pp. 40, 41-42, 45. Also: IPERS Overview slides (2025); IPERS web pages; Iowa Code §§ 97B.1A, 97B.49A, 97B.49G; Iowa Admin. Code r. 495—12.1. Last reviewed .