TSP Calculator: Contributions, Agency Match and Growth

Updated October 8, 2026. Quick answer: A federal employee under FERS gets agency money in the Thrift Savings Plan (TSP) in two parts: 1% of basic pay whether or not you contribute, and a match of dollar for dollar on the first 3% you contribute and 50 cents on the dollar on the next 2% (5 U.S.C. 8432(c)). Computed for $60,000 of pay, contributing 5% is $3,000 a year from you and $3,000 from the agency (computed), while 3% draws only $2,400 (computed). The 2026 limit is $24,500, $32,500 from age 50 and $35,750 at 60 to 63. This page projects your balance from your own pay, contribution rate and return. The return is your assumption, not a forecast.

Project your TSP balance

This page adds up what you and your agency put into the Thrift Savings Plan each month until you retire, applies the 2026 annual limits, grows the balance at the yearly return you enter, and shows the result. It runs on this page and sends nothing anywhere. The return and the raise are assumptions you set; the match and the limits are the law. Choose CSRS if you are covered by the Civil Service Retirement System, which has no agency contribution.

The dollar limits are held at their 2026 amounts for every year of the projection, and the first year runs from January with contributions at the end of each month. Real limits are adjusted by the IRS each year, so a long projection is a rough guide, not a promise.

What your agency adds under FERS

The statute sets two agency contributions. The first does not depend on you: “the employing agency shall contribute to the Thrift Savings Fund for the benefit of such employee or Member the amount equal to 1 percent of the basic pay of such employee or Member for such pay period”. The second is the match, and it is paid only when you contribute. It is the sum of “such portion of the total amount of the employee’s or Member’s contribution as does not exceed 3 percent of such employee’s or Member’s basic pay for such period” and “one-half of such portion of the amount of the employee’s or Member’s contribution as exceeds 3 percent, but does not exceed 5 percent, of such employee’s or Member’s basic pay for such pay period”. In plain terms the agency matches your first 3% dollar for dollar and your next 2% at 50 cents, so contributing 5% of pay brings the agency to 5% of pay in total. Computed for $60,000 of pay, the agency money by contribution rate:

Contributing nothing still brings the 1% ($600 a year on that pay, computed). Contributing more than 5% adds nothing to the agency amount. The match is worked out for each pay period on what you contribute in that period, so a contribution that hits the annual limit early in the year can stop the match for the remaining periods; this page spreads a capped contribution evenly over the year.

The 2026 contribution limits

The IRS sets the dollar limits, and its announcement names the TSP: “The annual contribution limit for employees who participate in 401(k), 403(b), governmental 457 plans, and the federal government’s Thrift Savings Plan is increased to $24,500, up from $23,500 for 2025.” The catch-up amount: “The catch-up contribution limit that generally applies for employees aged 50 and over who participate in most 401(k), 403(b), governmental 457 plans, and the federal government’s Thrift Savings Plan is increased to $8,000, up from $7,500 for 2025.” The statute lets an eligible participant contribute beyond the ordinary limit: “an eligible participant (as defined by section 414(v) of the Internal Revenue Code of 1986) may make such additional contributions to the Thrift Savings Fund as are permitted by such section 414(v)”. For ages 60 to 63 the notice says “age 60, 61, 62, or 63 in 2026 remains $11,250”. The totals, with the last one computed as 24,500 plus 11,250:

The notice also sets the pay the plan can take into account: “The annual compensation limitation under sections 401(a)(17), 404(l), 408(k)(3)(C), and 408(k)(6)(D)(ii) is increased from $350,000 to $360,000.” That is why the pay box stops at $360,000. Computed for $200,000 of pay and a request of 20% of pay, which is more than the limit, the first year is held to $24,500.00 at 40 (computed), $32,500.00 at 55 (computed) and $35,750.00 at 61 (computed). Whether catch-up money has to go in as Roth depends on the prior year’s pay; the rule is on the Roth catch-up page, and the whole catch-up stack is on the retirement catch-up calculator. Limits across plans are on the 2026 401(k) limits page.

What contributing more is worth over time

Computed for a 35-year-old with $60,000 of pay, a 2% yearly raise, no balance yet and 5% of pay contributed until 65, the balance depends heavily on the return you assume. The difference between the columns is what the agency adds, with its growth:

The contribution rate matters as much as the return. Computed for the same person at a 6% return, 0% contributed still builds $62,319.65 from the agency’s 1% alone, while 3% builds $436,242.09, 5% builds $623,206.45 and 10% builds $934,808.51 (computed):

The same 5% contribution under CSRS, with no agency money, builds $311,602.90 at a 6% return (computed), $311,603.55 less than under FERS. These are arithmetic on the numbers you enter, not a prediction. Real returns vary year to year, the funds you choose set them, and the fees, taxes and inflation are not in this projection.

CSRS and uniformed service

Employees under the older Civil Service Retirement System may contribute but receive nothing from the agency: “No contributions may be made by an employing agency for the benefit of an employee or Member under section 8432(c) of this title.” Members of the uniformed services have their own matching rules, which this page does not model; use the FERS setting only if you are a FERS employee.

Choices a balance projection does not make

1. Whether to keep the money in the TSP. The cost comparison with an IRA is on the keep the TSP or roll it page.

2. How the TSP fits with the annuity and Social Security. The order in which the three start is on the FERS, TSP and Social Security page, the pension itself is on the FERS retirement calculator, and the bridge payment is on the FERS supplement calculator.

3. How withdrawals are taxed and required. The Roth side is on the Roth TSP rules page. Whether to pay for advice is covered on the federal employees advisor page.

Where this calculator stops, and how it was checked

It projects one account for one person with one return, one raise and one contribution rate for every year. It does not model the uniformed services; part-year or part-time pay; the 26-period pay calendar (it uses 12 monthly periods); contributing a flat dollar amount instead of a percentage; contributions from a lump sum such as a bonus; Roth versus traditional tax treatment; loans; fund fees; taxes on withdrawals; or inflation. A balance you enter is treated as the starting balance on January 1. Your own facts decide the outcome. The TSP’s own calculators on tsp.gov could not be driven from here because the site refuses automated requests, so no comparison with them is claimed.

How it was checked: the agency formula is the statute’s own two clauses, and the limits are read from the IRS notice. A second program, written separately with exact fractions and the limits parsed from the notice’s text, agreed with the first on 60,000 random combinations of system, ages, pay, contribution rate, balance, return and raise. Seven hand-worked cases at the 3% and 5% breakpoints, from the statute’s wording alone, came out the same in both. The script on this page was driven in a real browser against the first program.

Common mistakes

• Contributing 3% and assuming that is the whole match. The agency also matches the next 2% at 50 cents on the dollar, so the full match needs 5%.
• Forgetting the 1% automatic contribution. It arrives even when you contribute nothing, which is why a FERS account grows without your contributions.
• Treating a projection as a forecast. The return is the number you typed in, and real returns vary.
• Using the same limit at every age. The catch-up amount starts in the year you reach 50, and the higher one applies only at 60 to 63.
• Expecting the match under CSRS. The statute allows no agency contribution there.

Related: FERS, TSP and Social Security sequencing, keep the TSP or roll it to an IRA, FERS retirement calculator, retirement catch-up calculator, and Roth TSP rules.

Sources

• 5 U.S.C. 8432, Contributions (Thrift Savings Plan; U.S. Code, 2023 Edition, U.S. Government Publishing Office): https://www.govinfo.gov/content/pkg/USCODE-2023-title5/html/USCODE-2023-title5-partIII-subpartG-chap84-subchapIII-sec8432.htm
• 5 U.S.C. 8351, Participation in the Thrift Savings Plan (U.S. Code, 2023 Edition, U.S. Government Publishing Office): https://www.govinfo.gov/content/pkg/USCODE-2023-title5/html/USCODE-2023-title5-partIII-subpartG-chap83-subchapIII-sec8351.htm
• IRS Notice 2025-67, 2026 Amounts Relating to Retirement Plans and IRAs: https://www.irs.gov/pub/irs-drop/n-25-67.pdf
• IRS news release IR-2025-111, 401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500: https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500

Read from the U.S. Code and the IRS pages linked above on October 8, 2026. General information, not legal or tax advice, and not a TSP or agency estimate. Your own facts decide the outcome, and the TSP, your agency benefits office or a benefits advisor is the right place to confirm anything consequential.