The moment you are in BRS, the government starts saving for you. Starting 60 days after you enter service, the Department of Defense deposits 1% of your basic pay into your Thrift Savings Plan every pay period, whether you contribute a dime or not. It costs you nothing, requires no action, and keeps flowing through the end of the pay period in which you reach 26 years of service. You become vested in this automatic money, meaning it is truly yours to keep, after completing two years of service.
Members who entered before January 1, 2018 and opted into BRS during the 2018 window started receiving the 1% automatically right away instead of waiting 60 days. Either way, the rule to remember is simple: the 1% is yours as long as you serve two years.
The match is where the real money is, and it starts after you complete two years of service. From that point, the government matches your own TSP contributions up to 4% of basic pay, on top of the automatic 1%. The matching formula is: dollar for dollar on the first 3% of basic pay you contribute, and 50 cents on the dollar for the next 2% you contribute. So if you put in 5% of basic pay, the government adds 4% in matching plus the 1% automatic, for a total government contribution of 5% and a total of 10% of your basic pay flowing into the account.
Here is the part people miss: you only get the full 4% match if you contribute at least 5% yourself. Contribute 3% and you get the 1% automatic plus a 3% match, leaving 1% of free money on the table every pay period. Over a 20-year career that abandoned 1% can compound into tens of thousands of dollars. New BRS members are automatically enrolled to contribute 3% of basic pay, which is a good start but not enough to capture the full match; bumping to 5% is the single highest-return move in the whole system.
One timing trap: if you hit the annual elective deferral limit before December, your contributions stop, and when your contributions stop, the matching stops too. Members who max out early in the year can accidentally forfeit months of matching. Spread contributions across the full year if you are anywhere near the limit.
You are always vested in your own contributions and their earnings; that money is yours from day one. The government money, both the 1% automatic and the matching, vests after two years of service from your Pay Entry Base Date. Leave before two years and the government contributions go back; stay two years and they are yours forever.
When you separate or retire, the TSP is fully portable. You can leave the balance in the TSP, which has some of the lowest investment fees in the industry, or roll it into a civilian 401(k) or IRA. The account does not vanish when you take off the uniform, which is exactly why BRS is dramatically better than High-3 for the majority of members who serve fewer than 20 years.
Contributions without an investment choice default into an age-appropriate Lifecycle (L) fund, a diversified mix that automatically gets more conservative as you age. That default is reasonable for most members. The G fund is the safe option, government securities that never lose nominal value but barely beat inflation. The C, S, and I funds are stock index funds with higher expected returns and real volatility. Young members with decades ahead have historically done best holding mostly stock funds through market swings, but the honest answer depends on your risk tolerance. What matters most under BRS is not picking the perfect fund; it is contributing at least 5% so the match keeps flowing.
Up to 5% of basic pay: a 1% automatic contribution starting 60 days after you enter service, plus up to 4% in matching contributions after you complete two years of service. You must contribute at least 5% yourself to get the full match.
After completing two years of service from your Pay Entry Base Date. Your own contributions and their earnings are always vested immediately.
The vested balance is yours and fully portable. You can leave it in the TSP, which has very low fees, or roll it into a civilian 401(k) or IRA.
New BRS members are automatically enrolled to contribute 3% of basic pay to the TSP. You can change or stop that at any time, but raising it to 5% captures the full government match.
Figures current as of October 2026. Sources: Military OneSource / DoD military pay publications. This guide is general information, not financial advice.