Washington TRS · How we calculate

How we estimate Washington TRS pensions

Everything the Washington calculator does, where each rule comes from, how we test it, and the points the sources leave open.

In short: the calculator picks your plan from your dates (which plan), applies the formula (2% or 1% × years × AFC), uses DRS's early retirement factors, and shows the survivor options from DRS's published factors. Try the calculator.

What the calculator does

  1. Picks your plan from the date you joined: Plan 1 before Oct. 1, 1977. Later, the plan you enter, or the default for your hire date (Plan 3 for July 1, 1996 - June 30, 2020, Plan 2 otherwise).
  2. Projects your service. We add one year of service for each year from today to your start date, unless you tell us you've left.
  3. Checks eligibility on your start date. Plan 1: 30 years at any age, 25 at 55, 5 at 60. Plan 2: 65 with 5 years, or 55 with 20. Plan 3: 65 once vested, or 55 with 10. Ages count from the 1st of the month after your birthday month.
  4. Figures the pension: 2% (Plans 1 and 2) or 1% (Plan 3) × years × your monthly AFC, capped at 60% of AFC in Plan 1.
  5. Applies the early retirement factor in Plans 2 and 3 before 65: the actuarial factor (DRS's administrative-factor table for years and months early, 2026 table through Dec. 2026 and 2027 table after) with under 30 years; with 30+ years, the 2008 factor (or the 3% factor if you pick it) if first hired before May 1, 2013, or 5% a year by month if hired later.
  6. Adds Plan 3 indexing if you left with 20+ years: 0.25% a month, compounded, from leaving to the start date or 65.
  7. Prices payment options with DRS's administrative factors: survivor factors by age difference (your age minus your survivor's, whole years), and for Plan 1 the Option 1 and Optional COLA factors by age.
  8. Shows the COLA at its 3% cap (the most it could be), starting the first July 1 after a full year of retirement.
  9. Shows the work rules: the 30-day wait, the 867-hour limit, and the first-month cut.

Privacy

Your inputs stay in your browser. They're saved in the part of the web address after "#", which is never sent to our server or to analytics.

Tested against DRS's examples

Tested against DRS's examples (Washington TRS)
ExamplePrintedOur resultMatch
Plan 1: 23 years, $5,400 AFC
DRS Washington TRS Plan 1 page, Your income: Example
$2,484$2,484✓ yes
Plan 2: 23 years, $5,400 AFC
DRS Washington TRS Plan 2 page, Your income: Example
$2,484$2,484✓ yes
Plan 3: 23 years, $5,400 AFC
DRS Washington TRS Plan 3 page, Your income: Example
$1,242$1,242✓ yes
Plan 2 at 55, 22 years, actuarial factor
DRS Washington TRS Plan 2 page, Early retirement examples, Example 1
$648.17$648.17✓ yes
Plan 3 at 55, 22 years, actuarial factor
DRS Washington TRS Plan 3 page, Early retirement examples, Example 1
$324.08$324.09≈ rounding
Plan 2 at 60, 30 years, 2008 factor
DRS Washington TRS Plan 2 page, Early retirement - Joined before May 1, 2013, Example 2
$2,508$2,508✓ yes
Plan 3 at 60, 30 years, 2008 factor
DRS Washington TRS Plan 3 page, Example 2 (2008 ERF)
$1,254$1,254✓ yes
Plan 2 at 62, 30 years, 5% factor
DRS Washington TRS Plan 2 page, Early retirement - Joined on or after May 1, 2013, Example 2
$2,244$2,244✓ yes
Plan 3 at 62, 30 years, 5% factor
DRS Washington TRS Plan 3 page, Example 2 (5% ERF)
$1,122$1,122✓ yes
Plan 3 indexing: stop at 64, start at 65
DRS Washington TRS Plan 3 page, Benefit indexing example
$1,030$1,030.42≈ rounding
Plan 3: work to 65 instead
DRS Washington TRS Plan 3 page, Benefit indexing example
$1,050$1,050✓ yes
Plan 1 Post-30: not joining
DRS Washington TRS Plan 1 page, How much difference can this choice make?
$2,775$2,775✓ yes
Plan 1 Post-30: joining
DRS Washington TRS Plan 1 page, How much difference can this choice make?
$2,675$2,675✓ yes
State rule: 8 years 11 months early
WAC 415-02-320(3)(a)
$589.16$589.16✓ yes
State rule: Plan 1 death before retirement
WAC 415-02-320(3)(c)
$1,134.73$1,134.73✓ yes
Application: buy 60 months, monthly increase
DRS TRS23RAPP 11/2022, p. 12
$300$300✓ yes
Application: buy 60 months, cost
DRS TRS23RAPP 11/2022, p. 12
$42,981$42,981✓ yes

"≈ rounding": DRS's Plan 3 page drops the last fraction of a cent ($324.09 shows as $324.08); we round, as the state rule's examples do. DRS's Francis example uses a simple 3% a year; the law compounds 0.25% a month, which we follow. Our automated tests also check the factor tables against DRS's published tables, plan and eligibility dates (Oct. 1, 1977; July 1, 1996; July 1, 2020; May 1, 2013), vesting edges, the 60% cap, survivor and Plan 1 factors, COLA banking and DRS's July 2026 COLA table, and the first-month work cut.

What we don't do

Points the sources don't settle

Each of these shows a "Check with DRS" label wherever it matters on this site.

erf table effective date

Why: The Administrative Factors page says the 2026 workbook is effective through Dec. 31, 2026 and lists a 2027 workbook, but no saved source states the 2027 start date or which table applies to a retirement date vs. an application date. What would settle it: DRS notice or the OSA letter that accompanies the 2027 factors.

erf pre 2026

Why: Only the 2026 and 2027 tables are saved; retirements before 2026 used older factors (the TRS23RAPP and plan pages call their tables illustrative). What would settle it: Prior-year administrative-factor workbooks (not needed for future retirements).

erf2008 monthly proration

Why: RCW 41.32.765(3)(b)(i) lists the 2008 ERF by whole retirement age; no source says whether months between birthdays are prorated (the 5% ERF is explicitly 'prorated monthly'). Engine uses age in completed years. What would settle it: WAC 415-02-320 text on alternate early retirement or a DRS estimate for a mid-year age.

erf3pct proration

Why: 3% ERF proration between birthdays is not stated; engine prorates monthly (3% x months early / 12). What would settle it: DRS rule or estimate; low priority since 2023 c 410 recalculates 3% ERF retirees under the 2008 ERF.

erf2008 return to work

Why: The 11/2022 application says 2008 ERF retirees lose benefits for any month worked before 65 (with an 867-hour nonadministrative exception); current statute and DRS pages do not mention it. What would settle it: Current DRS 'Thinking About Working After Retirement?' publication or WAC 415-112.

js age difference sign

Why: The J&S tables are indexed by 'Age Difference' (-20 to +40) without saying which age is subtracted. Factors fall as the difference rises, which fits member age minus survivor age (younger survivor = bigger reduction); engine assumes that and rounds to whole years. What would settle it: OSA letter accompanying the factors, or a DRS estimate showing both ages.

plan1 option chain

Why: Washington TRS Plan 1 survivor options: no source says whether the J&S factor applies to the Maximum Option or to Option 1. Engine applies it to Option 1 (Options 2-4 share Option 1's refund feature). What would settle it: DRS Washington TRS 1 estimate showing Maximum, Option 1 and Option 2-4 amounts with ages.

plan1 optional cola factor base

Why: Optional COLA factor (Appx F) is by age; engine multiplies the chosen option's amount by it. Not confirmed. What would settle it: DRS Washington TRS 1 estimate with and without the optional COLA.

age lookup rounding

Why: Option 1 and optional COLA factors are by whole age; engine uses age in completed years at the retirement date. What would settle it: OSA factor letter or a DRS estimate.

plan23 negative cola

Why: DRS pages don't say whether a Plan 2/3 COLA can be negative. RCW 41.32.770 uses the index ratio with a floor at the original allowance. Engine's projection lets the benefit fall toward (never below) the original amount, and limits each year to +/-3%. What would settle it: OSA COLA methodology or a DRS statement.

may2013 date meaning

Why: The 5% ERF rule turns on when you 'first become employed by an employer in an eligible position' (RCW 41.32.765(3)(c)); engine uses the hire/membership date input. What would settle it: Member's DRS account (membership date).

plan3 vesting after 44

Why: Plan 3 5-year vesting needs 12 service credit months after age 44; the engine cannot see the service history, so the caller must say so (default: assumed only if the member was 44+ at least 12 months before the retirement date and has 5+ years). What would settle it: Member's service credit history.

qualifying age date

Why: Retirement date is the first of the month after qualification; the sources don't say whether reaching an age on the 1st of a month qualifies for that same day. Engine: first of the month after the birthday month (matches the Jan. 15 -> Feb. 1 example). What would settle it: DRS rule (WAC 415-02) on attaining age.

plan1 2026 increase

Why: DRS says eligible PERS 1/Washington TRS 1 retirees get a one-time permanent 3% increase from July 2026 but the eligibility rules are in a news article not saved. What would settle it: DRS news article on the 2026 Plan 1 increase or the 2026 session law.

pebb subsidy

Why: No PEBB retiree premium or subsidy amounts in the saved sources; HCA (not DRS) administers them. What would settle it: HCA 'Thinking About Retirement?' or PEBB retiree enrollment guide (hca.wa.gov).

social security

Why: Saved sources don't state Social Security coverage for Washington TRS members. What would settle it: DRS or OSA statement on Section 218 coverage for Washington TRS.

plan1 age55 wording

Why: See contradictions 'plan1-age55'. What would settle it: DRS confirmation; statute and WAC already say no reduction.

service projection

Why: Eligibility dates assume one year of service per year of continued work before/after the retirement date (part-time and summer months earn less, see serviceCredit). What would settle it: Member's projected service from the DRS Benefit Estimator.

rtw 7 hour units

Why: RCW 41.32.802(1) reduces the benefit '5.5% for every seven hours worked'; engine counts whole 7-hour blocks (floor). What would settle it: WAC 415-112 rule text or a DRS example.

Where the sources disagree

Sources

This site isn't affiliated with the Washington State Department of Retirement Systems or Washington TRS. DRS decides your benefit; your DRS online account has official estimates.

Try the calculator →

Source: DRS plan pages for Washington TRS Plan 1, Plan 2 and Plan 3 (the DRS member handbook is now published as these web pages), retrieved Nov. 11, 2026, DRS plan pages (Plan 1, Plan 2, Plan 3); DRS COLA page; DRS Returning to Work page; TRS23RAPP (11/2022) pp. 3, 4, 6, 12, 14; TRS1RAPP (11/2022) p. 3; DRS administrative factors 2026; RCW 41.32.498, 41.32.530, 41.32.570, 41.32.760, 41.32.765, 41.32.770, 41.32.802, 41.32.840, 41.32.845, 41.32.875; WAC 415-02-320. Last reviewed .