When Congress created the Blended Retirement System, it did not force anyone into it. Everyone who entered service on or after January 1, 2018 was automatically enrolled in BRS with no choice. Everyone who entered before January 1, 2006 stayed in the legacy system with no choice. The only people who got a decision were those in the middle: members serving on December 31, 2017, with fewer than 12 years of service as measured from their pay entry base date. That group had all of calendar year 2018, and only 2018, to opt into BRS. The choice was irrevocable, and it required completing the official BRS opt-in training course first.
Members who did nothing stayed in the legacy system by default. The Department of Defense deliberately took no position on which system was better for any individual, calling it a personal financial decision that varies with circumstance. What the department did do was flood the force with training, calculators, and financial counselors, because the decision could not be undone.
Looking back, the pattern of who opted in tells you most of what you need to know. Junior members with few years of service opted in at high rates, which makes sense: they had the least pension to give up and the most years of TSP matching ahead of them. Senior members close to 20 years mostly stayed put, which also makes sense: they were a few years from a 50%-of-base pension and the 2.0% haircut would have cost them dearly with little time to make it up through compounding.
The members in the middle faced the genuinely hard call, and many of them decided on gut feeling rather than math. That is unfortunate, because the math is actually straightforward. The trade has exactly three moving parts: the pension gap, the TSP match, and continuation pay. Price those three and the answer usually reveals itself.
The cost of switching was the 20% pension haircut, locked in for life. For an E-7 with a high-3 average of $5,500 a month, High-3 pays $2,750 a month at 20 years and BRS pays $2,200. That $550 monthly gap, $6,600 a year, grows with cost-of-living adjustments for the rest of the retiree's life. Over a 30-year retirement it totals roughly $200,000 in nominal dollars before COLA, and more with it. That is the price. Everything else in BRS has to earn it back.
Continuation pay offsets part of it. A mid-career bonus of 2.5 to 13 times monthly basic pay, invested rather than spent, compounds for the remaining years of service. At the 2.5 floor for our E-7, roughly $13,750 invested at age 32 growing at 7% for 10 more years of service becomes about $27,000. Helpful, but not decisive on its own.
The TSP match is the piece that can actually close the gap. The government contributes up to 5% of basic pay every year: 1% automatic plus up to 4% in matching when the member contributes 5%. For a member averaging $70,000 in basic pay, that is $3,500 a year of government money. Compounded at 7% over a 15-year remaining career, the government contributions alone grow past $88,000, and the member's own matched 5% doubles the effect. For members with 10 or more years of compounding ahead, the match plus continuation pay can genuinely exceed the pension gap in present-value terms. For members with 3 years left, it mathematically cannot.
The opt-in window closed years ago, but the framework still matters, because every BRS member is living the trade right now. Ask three questions. First, will you serve 20 years? If the answer is probably not, BRS already won: the legacy system pays nothing before 20 years, and your vested TSP balance is real money. Second, are you contributing at least 5% to the TSP? If not, you are living the worst version of BRS: the smaller pension without the match that justifies it. Fix that before anything else. Third, are you treating continuation pay as retirement money? Members who invest the bonus capture its full value; members who spend it leave the pension gap unfilled.
The members who lost in 2018 were the ones who switched for the bonus and the match and then never contributed enough to earn the match. The members who won were the ones who understood that BRS is a savings system with a pension attached, not a pension system with a savings option. That distinction is still the whole game.
Members serving on December 31, 2017, with fewer than 12 years of service from their pay entry base date. They had calendar year 2018 only to make the irrevocable choice, after completing the official opt-in training.
No. The 2018 opt-in window was the only chance, and the choice was irrevocable. Members who entered on or after January 1, 2018 are in BRS permanently; earlier entrants who did not opt in remain in the legacy system.
A 20% smaller pension for life (2.0% multiplier instead of 2.5%) in exchange for up to 5% of basic pay in government TSP contributions, a mid-career continuation pay bonus, and a lump sum option at retirement.
Contribute at least 5% of basic pay to the TSP so you capture the full government match. Without the match, BRS is just a smaller pension; with it, the system works as designed.
Figures current as of October 2026. Sources: Military OneSource / DoD military pay publications. This guide is general information, not financial advice.