How does an Idaho PERSI pension work? A complete guide for members near retirement

The Base Plan formula, Rule of 90 and Rule of 80, early retirement cuts, COLA, survivor options, the Choice Plan, sick leave for insurance and how to apply.

Rules checked October 18, 2026, against persi.idaho.gov and ssa.gov

Who PERSI covers

PERSI (the Public Employee Retirement System of Idaho) covers employees of the State of Idaho, public school districts and charter schools, and many cities, counties and other local employers. Its main pension is the Base Plan, a defined benefit plan that pays a monthly check for life. PERSI also runs the voluntary Choice 401(k) Plan.

Members fall into two groups. General members are most employees, including teachers and office staff. Police and firefighter members (PERSI also calls them public safety officers) have a higher multiplier and earlier ages. Most members are vested, meaning they've earned a right to a pension, after 60 months of service (PERSI: Member Handbook).

The pension formula

multiplier × average monthly salary × years of service = monthly pension

• Multiplier: the 2.0% and 2.3% rates apply to service on or after July 1, 2000. Older service can use different rates, which your PERSI estimate will show.
• Average monthly salary: your highest average gross pay over a base period of consecutive months, usually near the end of your career. It is 42 months if your last contribution was after October 1, 1994. Very old accounts used 48 to 60 months.
• Service: PERSI counts service in months, so 30 years and 6 months is 30.5 years in the formula.

Sources: PERSI: Member Handbook and PERSI: Retirement Options.

Retirement ages and the Rule of 90 or 80

You get an unreduced (full) benefit if you retire at service retirement age, which is 65 for general members and 60 for police and firefighters. You can also get it earlier under the Rule of 90 (general) or Rule of 80 (police and fire): if your age plus your years of service add up to 90 or 80, and you've reached the minimum age, there's no cut. PERSI actually counts in months: age in months plus service in months must reach 1,080 (Rule of 90) or 960 (Rule of 80).

If you retire before you qualify, PERSI reduces your benefit by the smaller of two gaps: the years until service retirement age, or the points until the Rule of 90 or 80. The cut depends on how many years early that is:

That's 3% a year for the first five years and 5.75% a year for the next five. The reduction uses the law in effect at your last contribution, and PERSI's chart is in whole years, so ask PERSI for the exact figure for a partial year (PERSI: Early Retirement). Members with both general and police or fire service have a minimum age between 50 and 55.

A worked example

Yearly cost-of-living raises

PERSI's raise is called the postretirement allowance adjustment, or PAA. It takes effect each March and is based on the change in the consumer price index (CPI-U) from August to August.

• Automatic 1%: when inflation is 1% or more, a 1% raise is granted by law the next March. No vote is needed.
• Discretionary raise: if inflation is higher, the PERSI Board may recommend up to 5% more, for a total of no more than 6% and no more than inflation. The Legislature can reject or change it within its first 45 days; otherwise it takes effect. The Board can only recommend it if the plan is funded well enough to afford it.
• Retroactive raises: the Board can also recommend making up for past years when raises fell short of inflation, again subject to the Legislature.
• Floor: a PAA can never lower a benefit below its starting amount.

Sources: PERSI: 2025 Retiree Townhall on the PAA and PERSI: Retirement Options. For 2026, the automatic 1% PAA took effect March 1, 2026 (PERSI: 2026 PAA follow-up).

Survivor options

When you apply, you choose how your Base Plan pension is paid. A contingent annuitant (CA) is the person who keeps getting payments after you die.

Option 3 is a Social Security leveling option: it pays more before Social Security starts so that your total income is steadier. It is only available if you retire before your Social Security full retirement age, and it uses a Social Security quote you send to PERSI. If your CA dies before you, Options 1 and 2 rise to the Regular amount, and Options 4A and 4B rise to the Option 3 amount. On the Regular option, a beneficiary can get a death benefit if your payments haven't yet exceeded your contributions plus interest. You can change your option only within five business days after your first payment, with a few exceptions for later marriage (PERSI: Retirement Options).

The Choice 401(k) Plan

The Choice 401(k) Plan lets members save extra money through payroll deductions and invest it. Some employers add matching or other contributions, which are fully vested when made. Gain sharing money that the PERSI Board can credit to members falls under a separate tax rule, Internal Revenue Code section 414(k) (PERSI: Choice 401(k) Plan employer contributions). The Choice Plan is separate from your Base Plan pension, and its balance depends on what was put in and how the investments did.

Sick leave for health insurance

PERSI doesn't run a retiree health plan, but it can hold money from your unused sick leave to pay insurance premiums. Eligible retirees can convert up to half of their unused sick leave into a sick leave account. Your employer reports your balance to PERSI when you retire.

• State of Idaho retirees (Idaho Code 67-5333) can use it for premiums on state-maintained health, dental, vision, long-term care, prescription drug and life insurance. The state Office of Group Insurance lists approved carriers.
• School district and charter school retirees (Idaho Code 33-1228) can use it for employer-maintained group health, long-term care, vision, prescription drug and dental plans. Choices vary by district, so ask your HR office.

You enroll directly with the carrier, which bills PERSI each month until your balance runs out (PERSI: Insurance). For Medicare questions, Idaho's SHIBA program answers at 1-800-247-4422. If you retire before 65, see health insurance before Medicare.

Social Security and PERSI

PERSI and Social Security are separate, and PERSI can't answer Social Security questions. Many members also earn Social Security, and PERSI's Option 3 is built to work with it. Your pay stub shows whether Social Security tax is withheld.

If part of your career was in a job that didn't pay Social Security tax, two old rules used to cut your Social Security: the Windfall Elimination Provision (WEP) and the Government Pension Offset (GPO). The Social Security Fairness Act, signed January 5, 2025, ended both for benefits payable for January 2024 and later. If you never applied because of them, you may need to apply now (SSA: Social Security Fairness Act). See Does a pension reduce Social Security? and When should I start Social Security?

How to apply

Use PERSI's Application for Retirement (form RS121). Send it with your documents no earlier than six months and no later than 30 days before your retirement date. Your retirement date is always the first day of a month, usually the month after your last day of work. You'll need a government photo ID and proof of age and Social Security number for you and any CA, and form RS127 (Social Security quote) if you choose Option 3, 4A or 4B (PERSI: Application for Retirement, RS121).

What to do next

1. Find your Rule of 90 or 80 date. Add your age and service in months, and see when you reach 1,080 or 960.
2. Get a PERSI estimate. Ask for estimates at two or three dates and for each option you're considering.
3. Check your sick leave balance. Ask HR how much unused sick leave you have and which insurance plans can use it.
4. Get a Social Security quote. You'll need it for Option 3, 4A or 4B, and it helps you plan either way.
5. File between six months and 30 days out. Mark the window on your calendar.

General information, not advice. We aren't part of PERSI. For an official estimate of your Base Plan benefit, contact PERSI through persi.idaho.gov.