This page explains the Indiana TRF calculator. The rules it uses are explained in plain English on the formula, early retirement and payment options pages.
- 1
Find your account
From the date you joined and the two optional boxes, we say whether the Pre-'96 or '96 Account pays you. The formula is the same either way.
Hybrid Handbook p. 8, §2.1 Pre-1996 (Pre '96) Fund; p. 11, §3.1 - 2
Project your service
We add the time from today to your retirement date to the service you enter, one year per 12 months. The work-longer comparison adds a year of service for each year.
Our assumption (see below) - 3
Check the retirement rules
Your age (in whole months, on the 1st of the month) and service on the retirement date: 65 with 10, 60 with 15, the Rule of 85 at 55, or early at 50 with 15.
Hybrid Handbook p. 29, §7.1; Hybrid Handbook p. 32, §7.9 Early Retirement with a Reduced Benefit - 4
Apply the formula
Final average salary × 1.1% × years of service ÷ 12, the Five-Year Certain and Life amount, with the $185 minimum for unreduced pensions.
Hybrid Handbook p. 29, §7 Pension Benefits; p. 30, §7.4 Table 1 Pension Benefit Calculation Worksheet Example; Hybrid Handbook p. 35, §7.11 Minimum Retirement Pension Benefit - 5
Apply the early cut
The handbook's table by age (89% at 59 to 44% at 50), month by month in between, as INPRS's actuaries describe it.
Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit; '96 Account actuarial valuation (June 30, 2025), p. 57, Appendix B, Monthly Benefits Payable, Early retirement; Pre-'96 Account actuarial valuation (June 30, 2025), p. 54 - 6
Add the dates
Your earliest pension date and full-pension date if you keep working.
Hybrid Handbook pp. 29-30, §7.2 Retirement Effective Date; p. 30, §7.3
What the calculator doesn't cover
- Your DC account (the old ASA). It's paid on top of the pension, but its balance depends on contributions and investments.
- TRF My Choice account balances.
- Straight Life, the survivor options and Social Security Integration amounts. INPRS doesn't publish the factors.
- Your final average salary. We use the number you enter; INPRS figures it from your records.
- Disability, classroom disability, Millie Morgan and elected-official retirements, and the cost of buying service.
- COLAs and 13th checks, which happen only when the General Assembly passes them.
- Taxes, health premiums and other deductions. PERF and other INPRS funds.
How we check the math
The calculator runs on a small engine that reads every rule from one data file, with a source for each. Automated tests check it against every worked example in the TRF handbooks, plus the edges of each rule (birthdays, the 1995 and 2005 account dates, the ages 50, 55, 60 and 65, the 10- and 15-year marks). The tests run every time the site is built.
| Example | Source shows | Our engine | Source |
|---|---|---|---|
| Worksheet: $50,000, 30 years (a year) | $16,500 | $16,500 | Hybrid Handbook p. 29, §7 Pension Benefits; p. 30, §7.4 Table 1 Pension Benefit Calculation Worksheet Example Match |
| Worksheet: $50,000, 30 years (a month) | $1,375 | $1,375 | Hybrid Handbook p. 29, §7 Pension Benefits; p. 30, §7.4 Table 1 Pension Benefit Calculation Worksheet Example Match |
| Rule of 85: 55y 3m + 29y 9m | 85 | 85 | Hybrid Handbook p. 29, §7.1 NOTE Match |
| Early retirement at 59 | 89% | 89% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 58 | 84% | 84% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 57 | 79% | 79% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 56 | 74% | 74% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 55 | 69% | 69% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 54 | 64% | 64% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 53 | 59% | 59% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 52 | 54% | 54% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 51 | 49% | 49% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Early retirement at 50 | 44% | 44% | Hybrid Handbook pp. 32-33, §7.9 Retirement Age / Percent of Pension Benefit Match |
| Last day in pay 2025-08-02 | 2025-09-01 | 2025-09-01 | Hybrid Handbook pp. 29-30, §7.2 Retirement Effective Date; p. 30, §7.3 Match |
| My Choice vesting, 4 years 10 months | 80% | 80% | My Choice Handbook p. 13, §3.6.1 Example Match |
| Airtime with 15 years | 3 years | 3 years | Hybrid Handbook p. 22, Purchase 'Airtime' Service Credit (Examples) Match |
| Airtime with 6 TRF + 4 PERF years | 2 years | 2 years | Hybrid Handbook p. 22, Purchase 'Airtime' Service Credit (Examples) Match |
Things to check with INPRS
The sources don't settle these points. Each is labeled "Check with INPRS" where it shows up on the site.
We built these pages from INPRS's own handbook, reports and posts. We haven't yet checked them against the Indiana Code itself.
Where INPRS documents disagree, we follow the TRF Hybrid handbook.
Hybrid Handbook p. 5, §1.2 (the law governs if the handbook differs)The handbook's early-retirement table lists whole ages only, like 69% at 55 and 74% at 56. INPRS's actuaries describe the cut month by month, which puts ages in between at points between those figures.
We use the month-by-month rule. At 55 and 6 months, for example, that's 71.5% of your pension.
Hybrid Handbook pp. 32-33, §7.9; '96 Account actuarial valuation (June 30, 2025), p. 57The handbook doesn't say whether your age and service are counted on your retirement date (the 1st of the month) or on your last day at work.
We count your age in whole months on the retirement date you enter.
Hybrid Handbook pp. 29-30, §7.2INPRS doesn't publish how much each payment option changes your check. Straight Life pays more than Five-Year Certain and Life, and the survivor options pay less.
We show the Five-Year Certain and Life amount only. For the other options, use INPRS's calculator at myINPRSretirement.org.
Hybrid Handbook pp. 30-31, §7.4; pp. 35-36, §7.12The handbook says your average uses your highest five years of pay. It doesn't say whether those are school (July-June) years or calendar years, or how a part year counts.
We use the yearly average you enter. Your annual member statement or INPRS can confirm it.
Hybrid Handbook p. 31, §7.5The $185 monthly minimum is for retirees getting an unreduced pension. The handbook doesn't say how it works with survivor options.
We apply it only to unreduced pensions, on the Five-Year Certain and Life amount.
Hybrid Handbook p. 35, §7.11To find your earliest and full-pension dates, we assume you keep earning a full year of service each year you work.
One year of service per 12 months. A full-time teacher earns a year for 120 or more days in a July-June year.
Hybrid Handbook p. 14, §413th checks were also paid in fiscal years 2018 to 2021. We don't have the amounts from a source.
We show only the 2024, 2025 and 2026 amounts, from INPRS's posts.
'96 Account actuarial valuation (June 30, 2025), p. 58A 2026 law lets some vested My Choice members switch to TRF Hybrid, if their employer allows it. So far only INPRS's summary of the law describes it, not a handbook.
We describe it as INPRS's summary does. We don't model the switch.
INPRS 2026 Legislative Updates (July 9, 2026), SEA 14Where sources disagreed
- The handbook puts members who enrolled before July 1, 1995 in Pre-'96 (and first-time members after June 30, 1995 in '96). The ACFR describes TRF Pre-'96 DB as teachers 'hired before July 1, 1996'. Followed: the handbook. The benefit formula is the same either way. Hybrid Handbook p. 8, §2.1; INPRS ACFR FY2025 p. 30
- Handbook and ACFR: disability benefit minimum $185/month. Both actuarial valuations: $180/month. Followed: the handbook. Hybrid Handbook p. 34, Disability Benefits; INPRS ACFR FY2025 p. 31; '96 Account actuarial valuation (June 30, 2025), p. 57
- Handbook §10.2 says the 2025 13th check goes to members retired on or before December 1, 2024 'and was entitled to a benefit on July 1, 2054'. INPRS's Spring 2025 Legislative Update says July 1, 2025; 2054 is a typo. Hybrid Handbook p. 44, §10.2; INPRS Spring 2025 Legislative Updates (June 4, 2025)
- The handbook table gives the percent by whole age (50-59); the actuarial valuations state the reduction per month (0.1%/month 60-65 plus 5/12%/month below 60). They agree at whole ages. The engine uses the monthly rule. Hybrid Handbook pp. 32-33, §7.9; '96 Account actuarial valuation (June 30, 2025), p. 57
- The handbook ties Millie Morgan retirement to being 65 'as of June 30, 2023' (effective July 1, 2023); the ACFR and valuations describe it as an ongoing right at 65 with 20 years while active. Not used by the engine. Hybrid Handbook p. 32, §7.7; INPRS ACFR FY2025 p. 31
- The valuations list Option A-3 (Modified Cash Refund Annuity, with the DC account); the handbook lists only A-1, A-2, B-1, B-2, B-3 and Social Security Integration, and says DC money hasn't been annuitized by INPRS since 2018. Followed: the handbook. Hybrid Handbook pp. 29, 35-36; '96 Account actuarial valuation (June 30, 2025), p. 58
Sources
- Teachers' Retirement Fund Hybrid Plan Member Handbook Effective 07/01/2025 (48 pages)
- TRF My Choice: Retirement Savings Plan Member Handbook Effective 07/01/2025 (31 pages)
- TRF (Hybrid) At A Glance 7/1/2025
- TRF My Choice At A Glance 7/1/2025
- Teachers' Retirement Fund 1996 Account Actuarial Valuation Report June 30, 2025 (letter dated November 17, 2025)
- Teachers' Retirement Fund Pre-1996 Account Actuarial Valuation Report June 30, 2025
- INPRS Annual Comprehensive Financial Report FY2025, Financial Section Fiscal year ended June 30, 2025
- Understanding Indiana's Largest Pension System (INPRS) December 2025
- INPRS Destination: Retirement posts and Retiree News (13th checks, COLAs, legislative updates) retrieved 2026-11-11
We cite the page number printed on each handbook page. Last reviewed Nov. 12, 2026.
Source: Teachers' Retirement Fund Hybrid Plan Member Handbook, Effective 07/01/2025, pp. 5, 8, 11, 12, 14, 22, 29, 29-30, 30, 30-31, 31, 32, 32-33, 35, 35-36, 36. Also: '96 Account actuarial valuation (June 30, 2025) pp. 57, 58; Pre-'96 Account actuarial valuation (June 30, 2025) p. 54; My Choice Handbook p. 13; INPRS 2026 Legislative Updates (July 9, 2026), SEA 14. Last reviewed .
The INPRS documents we used don't say outright whether your teaching job pays into Social Security. They mention Social Security tax on your pay and offer a Social Security Integration option.
We don't estimate Social Security. Check your Social Security statement at ssa.gov.
Hybrid Handbook p. 12; p. 31; p. 36, §7.12