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Front-load your TSP and you forfeit real match money. Here is the exact cost.
The TSP match is computed per pay period — contribute nothing in December because you hit the limit in November and the December match is simply gone. Most TSP content never quantifies that loss. This calculator does: it applies the real FERS/BRS match formula (automatic 1%, dollar-for-dollar on 3%, half on the next 2%), caps your contributions at the 2026 limits, counts the matched periods, and shows both the forfeited match and the exact percentage election that maxes the year without losing a dime.
Federal employees and BRS service members use it to catch the per-pay-period trap: the 5% match is computed every period, so hitting the $24,500 cap early forfeits match outright. It shows the exact forfeiture and the percentage election that maxes the year with every period matched.
$24,500 of your own money (traditional and Roth combined) per IRS Notice 2025-73 and TSP Bulletin 25-3. Ages 50–59 and 64+ add $8,000 catch-up for $32,500; ages 60–63 get the SECURE 2.0 super catch-up of $11,250 for $35,750. Agency automatic and matching contributions do NOT count against your deferral limit — they fall under the separate $72,000 annual-additions cap.
FERS and BRS participants get an automatic 1% of basic pay plus matching: dollar-for-dollar on your first 3%, 50 cents per dollar on the next 2% — 5% total when you contribute 5%. The trap: the match is computed every pay period. Contribute 30% of a $95,000 salary and you hit the $24,500 cap in period 23; the last three periods have no contribution and no match — $438 forfeited. The fix is the exact election: limit ÷ pay, spread evenly (25.79% in that example).
Two things. First, catch-up contributions must now be made as Roth if your prior-year Social Security wages exceeded $150,000 — payroll handles it automatically, but your take-home drops since there is no deferral. Second, in-plan Roth conversions became available January 28, 2026. Unchanged but worth repeating: agency match always lands in the traditional balance even when you contribute Roth, and the automatic 1% vests after 3 years for FERS (2 for BRS) while your contributions and the match are always immediately yours.