TRS Illinois 2.2 Formula Upgrade

Tier 1 TRS members who began teaching before July 1, 1998, earned service credit under a graduated formula — 1.67% of Final Average Salary for the first 10 years, 1.9% for years 11–20, 2.1% for years 21–30, and 2.3% for years beyond 30. The 2.2 formula, adopted July 1, 1998, replaced that graduated schedule with a flat 2.2% per year of service for all years going forward.

If you have pre-July 1998 service, the upgrade lets you retroactively apply the 2.2% rate to those earlier years. For most long-career educators, the math favors upgrading.

How the Upgrade Cost Works

The base cost is calculated by TRS and depends on your salary history during the pre-1998 years. But the actual amount you pay can be significantly less, because post-1998 teaching service reduces the cost on a schedule:

• For every 3 years of TRS service taught after July 1, 1998, the upgrade cost for 1 year of pre-1998 service is eliminated.
• Members retiring with more than 34.0 years of total service credit receive a 25% reduction in remaining upgrade costs for each year beyond 34 — reaching a full 100% discount at 38.0 years.

So a Tier 1 member with 38 years of total service pays nothing for the upgrade. Someone with 30 years of post-1998 service has 10 years of pre-1998 costs eliminated, and the remainder depends on how many pre-1998 years they actually worked.

When It Makes Financial Sense

The upgrade matters most for members who spent a significant number of years under the old graduated formula. If you taught from 1985 to 1998 under the graduated schedule, those 13 years were credited at rates between 1.67% and 2.1%. Upgrading bumps all of them to 2.2%.

On a $95,000 Final Average Salary, the difference between 1.67% and 2.2% for one year is roughly $503 per year in pension income — and that compounds with the 3% annual COLA. Over a 25-year retirement, that one year of upgrade generates tens of thousands in additional income.

Members with only a year or two of pre-1998 service should still check the cost, but the payoff is smaller. Request a formal upgrade cost statement from TRS Member Services to see your specific numbers.

Payment Methods

Ask TRS which payment methods and payment deadline apply to your upgrade. A tax-deferred trustee-to-trustee transfer from a 403(b) or 457(b) may be available; confirm eligibility and transfer instructions with TRS and your plan administrator.

Log into MyTRSIL to check your current upgrade balance. If you're within 12 months of retirement, request the formal cost statement now so you have time to arrange payment.

One Piece of the Service Credit Puzzle

The 2.2 upgrade is just one component of your total service credit picture. Optional service purchases, reciprocal credit from SURS or IMRF, and unused sick leave conversion all interact with the final calculation. The TRS Illinois Retirement Guide walks through each one with a service credit audit worksheet so you can verify every year before filing your application.

See more Illinois guides →