- You can buy credit for some past service, including other Massachusetts public service (up to 20 years), substitute or part-time teaching (20), out-of-state public school teaching (10), Peace Corps (3) and military service (4). You must apply while a member in service and pay in full before you retire. Interest since 2023 is 7.00% (actuarial) or 3.5% (buyback).Ready for Retirement 2026 p. 3 and p. 5, Creditable service table
- Out-of-state and nonpublic school service count only if you have at least as many years of 'matching' Massachusetts membership service when you retire.Ready for Retirement 2026 p. 5, footnote 4
What you can buy
| Service | Up to | Interest |
|---|---|---|
| Other MA public service, not a member of a MA system | 20 yrs | 7% |
| Other MA public service, refund buyback | all | 3.5% |
| MA public school substitute, temporary or part-time teaching or tutoring | 20 yrs | 7% |
| Out-of-state public school teaching | 10 yrs | 7% |
| Nonpublic school teaching before 1973 | 10 yrs | 7% |
| Overseas dependent school teaching | 5 yrs | 7% |
| Vocational education work experience (Chapter 74) | 3 yrs | 7% |
| Nonpublic school teaching in a MA publicly funded school | 10 yrs | 7% |
| Peace Corps | 3 yrs | 7% |
| Pre-1975 maternity leave | 4 yrs | 7% |
| Active military service | 4 yrs | none on first invoice; then buyback |
Purchases must be applied for while you are a member in service (except Peace Corps and refund buybacks) and paid in full before your retirement date; late payment delays retirement. Interest since Jan. 1, 2023: actuarial 7.00%, buyback 3.5%. Out-of-state and nonpublic purchases need at least as many years of 'matching' Massachusetts membership service. Military service may be purchased up to one year after you reach 10 years of creditable service. Tier 2 members who took a refund get buyback interest only if they buy within one year of returning. Ready for Retirement 2026, p. 3, p. 4, p. 5 (Creditable service table and footnotes), p. 31
Credit for day-to-day substitute service is the number of full days worked divided by 180. Ready for Retirement 2026, p. 3
What a bought year is worth
Each year adds your age factor × your salary average, until you reach the 80% cap. Our illustration: retiring at 62 with 25 years on $80,000, one more year adds about $1,760 a year in Tier 1 and $1,400 in Tier 2. Bought years also count toward the 30 years for RetirementPlus. Ask MTRS for the cost and compare. See the age factor chart.
Questions
What service can I buy from MTRS?
You can buy credit for some past service, including other Massachusetts public service (up to 20 years), substitute or part-time teaching (20), out-of-state public school teaching (10), Peace Corps (3) and military service (4). You must apply while a member in service and pay in full before you retire. Interest since 2023 is 7.00% (actuarial) or 3.5% (buyback).
What interest does MTRS charge to buy service?
Since January 1, 2023: 7% actuarial interest for most purchases, or 3.5% buyback interest for refunded Massachusetts service.
Source: MTRS Ready for Retirement reference guide, 2026, pp. 3, 4, 5, 31. Last reviewed .