TSP Contribution Calculator
The Thrift Savings Plan is the defined-contribution retirement account for federal employees. FERS workers receive an automatic agency contribution of 1 percent of basic pay plus a match: dollar-for-dollar on the first 3 percent you contribute and 50 cents on the dollar for the next 2 percent, so contributing 5 percent earns the full agency 5 percent. This calculator takes your salary, your contribution percentage, and the annual elective deferral limit, computes your own contribution (capped at the limit), the agency automatic and matching contributions, and the combined total going into your account this year.
TSP contribution formula
Employee = min(salary * (pct / 100), deferral limit)
Automatic = salary * (auto% / 100)
Match = salary * [min(pct,3)% dollar-for-dollar + (next up to 2%) at 50%]
Match% = min(pct,3) + 0.5 * min(max(pct-3,0),2)
Total = employee + automatic + (salary * match% / 100)
The match caps at an effective 4 percent of pay (3 percent full plus 1 percent half-matched), plus the 1 percent automatic equals up to 5 percent agency money when you contribute at least 5 percent.
US TSP context
- FERS employees get a 1 percent automatic agency contribution even if they contribute nothing.
- Matching is dollar-for-dollar on the first 3 percent and 50 cents per dollar on the next 2 percent.
- Contributing at least 5 percent of pay captures the full agency contribution.
- Agency contributions do not count against your IRS elective deferral limit.
- Catch-up contributions are available to participants age 50 and older and are not modelled here.
TSP contribution: frequently asked questions
How does the TSP agency match work for FERS employees?
FERS employees receive an automatic agency contribution of 1 percent of basic pay, plus matching contributions: a dollar-for-dollar match on the first 3 percent you contribute and 50 cents on the dollar for the next 2 percent. Contributing at least 5 percent captures the full 5 percent agency contribution.
What is the elective deferral limit?
The IRS sets an annual elective deferral limit on your own TSP contributions. Because the dollar amount is adjusted each year, this calculator uses the limit you enter as a user-editable input and caps your contribution at that amount. Confirm the current limit with the IRS or TSP.
Does the agency match count toward the deferral limit?
No. The agency automatic 1 percent and matching contributions do not count against your elective deferral limit. Only your own employee contributions count toward that limit.
Do I lose the match if I contribute more than 5 percent?
No. You can contribute more than 5 percent up to the deferral limit, but the agency match maxes out at 5 percent of basic pay. Contributing less than 5 percent leaves matching money on the table.
Is this for FERS or CSRS employees?
The match modeled here is the FERS structure. CSRS employees can contribute to the TSP but generally do not receive agency matching contributions. Set the match inputs to zero to model a CSRS or unmatched account.
Official sources
- Thrift Savings Plan: TSP.gov (contributions and matching).
- U.S. Office of Personnel Management: OPM home (TSP for FERS).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.