Run the math on your TSP contributions, employer match, and BRS (Blended Retirement) match in one tool. Compare traditional vs. Roth TSP, hit the 2026 $24,500 elective limit precisely, and forecast end-of-career balance.
The Thrift Savings Plan (TSP) is the 401(k)-equivalent for federal employees and uniformed-services members. Get the contribution percentage right and your agency or military service matches up to 5% of basic pay — that's free money. Get it wrong and you literally leave thousands of dollars on the table every year.
This calculator solves the two questions every TSP participant should be asking: Am I capturing the full match? and Should I be in traditional or Roth TSP? It handles FERS civilian matching (1% automatic + dollar-for-dollar up to 3% + 50¢ on the dollar for the next 2% = 5% max), military BRS matching (same formula but capped at 5% of basic pay), and the legacy CSRS context where TSP has no match at all.
For 2026, the IRS elective deferral limit is $24,500 (up from $23,500 in 2025), the age-50 catch-up is $8,000, and the new age-60-to-63 super catch-up is $11,250. Hitting the elective limit too early in the year can cut you off from the match — the calculator's "even-out your contributions" feature shows the exact per-pay-period percentage to maximize matching across all 26 pay periods.
The Roth vs. traditional decision is mostly a function of your current tax bracket vs. your expected retirement bracket. The calculator runs both forward to show the break-even point and the after-tax balance in each scenario.
Step 1 — Enter your basic pay. For federal civilians, this is your base salary (not locality). For military, this is your base pay (not BAH, BAS, special pays). The 5% match is calculated on basic pay only.
Step 2 — Set your contribution percentage. The calculator validates you're hitting 5% to capture the full match. If you're trying to hit the IRS $24,500 limit, the tool shows the exact percentage to spread it evenly across 26 pay periods, so you never stop contributing mid-year and lose match.
Step 3 — Pick traditional or Roth. The calculator runs both. If your current marginal bracket is 12% or 22% and you expect to retire in a similar or higher bracket, Roth usually wins. If you're at 32%+ marginal now and expect to be in 22% or lower in retirement, traditional usually wins. The actual answer depends on your other retirement income and state-tax expectations.
Federal civilian, military, and FERS users: enter your salary, contribution %, and years to retirement — the calculator shows match captured, total balance projection, and Roth vs. traditional break-even.
Open the TSP calculator →$24,500 elective deferral (the IRS 402(g) limit, same as 401(k)/403(b)). Age-50 catch-up: $8,000. Age 60-63 super catch-up under SECURE 2.0: $11,250. The combined cap for employer + employee contributions in 2026 is $72,000 (IRS 415(c)) — relevant if you're maxing TSP and your agency makes large matching contributions.
For FERS civilians and BRS military: 1% automatic agency/service contribution (you get it whether you contribute or not), plus dollar-for-dollar match on your first 3%, plus 50¢ on the dollar for the next 2%. Maximum employer contribution = 5% of basic pay. You must contribute at least 5% to get the full match. CSRS civilians have NO TSP match. Military legacy (non-BRS) participants have no match.
Rule of thumb: if your current marginal tax bracket is 22% or below and you expect to retire in a similar or higher bracket, Roth usually wins. If you're at 32%+ and expect to retire in 22% or lower, traditional usually wins. The 24% bracket is a wash for most. The match always goes into traditional regardless of your contribution election — that part isn't Rothable.
BRS (Blended Retirement System, effective 2018) combines a smaller pension (2% × years × high-3, instead of 2.5%) with TSP matching and a mid-career continuation pay bonus. Legacy retirement (members who opted to stay or who joined before 2018) has the richer 2.5% pension formula but ZERO TSP match. BRS is mathematically better for most people who won't stay 20+ years; legacy is better for those certain to do 20+.
Age 59½ for in-service withdrawals or separation withdrawals. Special rule: federal employees who separate in or after the year they turn 55 (50 for special category employees like LEOs) can take TSP without the 10% early-withdrawal penalty. Roth TSP earnings need to satisfy the 5-year rule AND 59½ for tax-free treatment.