TSP Calculator

Introduction

The Thrift Savings Plan is the retirement savings account for federal civilian employees and members of the uniformed services. It was created by the Federal Employees' Retirement System Act of 1986 and has grown into one of the largest defined-contribution plans in the world, holding more than a trillion dollars for roughly seven million participants. The TSP behaves like a 401(k), but it has one feature almost no other employer plan can match: a guaranteed federal agency contribution that can give you an automatic return of up to 5% of your salary every single year, regardless of how the markets perform[opm-ri90-1].

That agency money is the single most valuable part of the plan, yet most online calculators ignore it. Generic retirement tools treat your TSP as if it were just another 401(k), letting you type in an "employer match" percentage by hand. The Retirement 401k Calculator does exactly that. This TSP Calculator instead embeds the real federal match rules, the actual contribution limits for 2026, and the published returns of every TSP fund, so your projection reflects the plan as it actually works.

In this calculator you can do two things. The first mode projects your TSP balance at retirement: you enter your salary, the percentage you contribute, your retirement system (FERS, BRS, or CSRS), your current balance, and the fund you are invested in, and it shows your projected balance, the separate contributions from you and your agency, and — critically — what percentage of the available match you are actually capturing. The second mode checks your 2026 TSP contribution limits, including the new catch-up rules for ages 60 through 63 and the SECURE 2.0 rule that forces high earners to make their catch-up contributions on a Roth basis[tsp-bulletin-25-3]. If you also save outside federal service, the Retirement Savings Gap Calculator can model your overall retirement picture, and the Retirement Contribution Calculator compares the TSP's 2026 limits against every other retirement plan you might hold in parallel.

How to Use

The calculator runs automatically as you change each field. Start with the mode selector: Project my TSP balance is the default, and Check my 2026 TSP limits is the second option.

In projection mode, the most important input is your retirement system, because it decides whether you get the agency match at all. FERS employees hired before January 1, 2018 receive the classic match, and employees under the Blended Retirement System (BRS, the default for uniformed services and civilians hired on or after January 1, 2018) receive an identical match after 60 days of service. CSRS employees — those covered by the old Civil Service Retirement System who never converted — receive no agency contributions, so the calculator correctly ignores the match for them.

Enter your annual base pay and the percentage you contribute from each paycheck. The TSP accepts contributions in whole percentages, so keep this simple. Enter your current TSP balance (leave it at zero if you are just starting), choose your fund, and set the years until retirement. The calculator uses each fund's actual 10-year average return as the default projection rate, but you can override it with your own expected return if you want to test a more conservative or aggressive scenario. The optional annual pay-raise field grows your contributions (and your agency's) each year, mirroring step increases and promotions.

Two quick examples. A FERS employee earning $80,000 who contributes 5% of pay for 20 years in the L 2050 Fund, starting from zero, ends with a projected balance of roughly $527,000 — about $400,000 of it compound growth, with $80,000 of their own money and $80,000 from the agency. The same employee contributing only 2% of pay would capture just half the available match and end up with a materially smaller balance. In limits mode, a 40-year-old earning $80,000 with biweekly pay sees a $24,500 limit, a target of $942.31 per paycheck to max out, and confirmation that their catch-up, if any, can stay in the traditional balance.

For more information, see the Average Return Calculator.

The Federal Agency Match

The federal match is a gift with strings, and the strings are generous. Under 5 CFR § 1600.19, your employing agency contributes two separate pieces[ecfr-1600]:

• Agency Automatic (1%): Every FERS and BRS employee receives a contribution equal to 1% of their basic pay every pay period, regardless of whether they contribute anything themselves.
• Agency Matching (up to 4%): The agency then matches your own contributions dollar-for-dollar on the first 3% of pay you contribute, and 50 cents on the dollar for the next 2% (from 4% to 5% of pay).

The combined formula, where c is your contribution rate as a percentage of pay, is:

So if you contribute nothing, you still bank 1% of your salary. If you contribute 3%, the agency adds 4% (1% automatic plus 3% matched). If you contribute 5% or more, the agency adds the full 5%: your 5% plus their 5% means you are investing 10% of your salary while only paying for half of it. There is no benefit to contributing more than 5% for match purposes — the match caps there — but the extra money still grows tax-deferred and counts toward your own annual limit.

Each year your balance grows at the fund return r, then receives your contribution plus the agency's. The calculator performs this loop year by year so that compounding, pay raises, and the match all interact the way they do in your real account.

Vesting matters. The agency automatic 1% vests after three years of FERS service, and after 60 days for BRS participants (uniformed services vest after two years). If you leave federal service before you vest, you forfeit that money — a strong reason to understand your vesting date before changing agencies[opm-ri90-1]. Matching contributions vest on the same schedule as the automatic 1%.

TSP Fund Returns

TSP offers five core funds and a series of Lifecycle (L) funds. The individual funds are low-cost index investments that track broad market benchmarks, and their long-run returns determine how much your money (and your agency's match) grows[tsp-fund-performance].

The table shows why fund choice dominates match choice over time. A 10-year G Fund projection turns a 5% employee contribution into a modest balance, because 2.92% barely outpaces inflation, while the same contribution in the C Fund compounds at 15.05%. To see how compounding alone reshapes those numbers before the match is added, run the same amounts through the Compound Interest Calculator. Lifecycle funds hold a glide path of the five core funds and become more conservative automatically as the target date approaches — the fund named for your approximate retirement year is the default starting point for most federal employees[tsp-lifecycle]. Return data above reflects net investment performance reported by the Federal Retirement Thrift Investment Board as of mid-2026[frtib-jan2026].

2026 Contribution Limits

Each year the IRS adjusts the maximum you can contribute to the TSP. The 2026 numbers follow the general 401(k) limits published in IR-2025-111 and appear in TSP Bulletin 25-3[tsp-bulletin-25-3][tsp-contrib-limits].

The catch-up picture changed twice in two years. Under SECURE 2.0 Section 109, participants who turn 60, 61, 62, or 63 in the calendar year get the higher $11,250 catch-up limit, while those turning 64 or older revert to the regular $8,000. And under SECURE 2.0 Section 603, which the TSP implemented on January 1, 2026, any participant whose prior-year wages from TSP-eligible positions exceeded $150,000 must make their catch-up contributions to the Roth TSP balance — traditional catch-ups are no longer available to them once they hit the $24,500 pre-tax maximum[tsp-bulletin-25-3]. This is why the calculator asks for your age, pay frequency, and prior-year wages in limits mode: the answer genuinely depends on all three.

The annual additions limit is the one most people miss. It caps employee plus agency contributions together at $72,000, so if you max out your own $24,500 plus your agency's 5%, you still have ample room before the $72,000 ceiling binds. Your own contribution choices, not the match, drive how quickly you approach it. The contributions themselves can be traditional (pre-tax) or Roth (after-tax), or any mix you elect through myPay, Employee Express, or your agency's payroll system[tsp-contrib-types].

Practical Tips

Contribute at least 5% of pay, always. At 5% you unlock the full federal match: your agency adds another 5% of your salary every year, which is a 100% return on that portion of your contribution before any investing happens. Below 5% you are literally refusing free money — the calculator's "match captured" figure makes the cost of under-contributing visible.

Do not chase a higher match by over-contributing. The federal match caps at 5%, so contributing 10% of pay earns the same agency contribution as contributing 5%. The extra 5% is still valuable tax-advantaged savings, but it is not "matched" — it is your money alone.

Pick a Lifecycle fund unless you have a reason not to. L funds are diversified, automatically rebalanced, and become more conservative over time. Building your own mix of G, F, C, S, and I requires deliberate rebalancing, and most federal employees who try it drift off course. If you want more control, compare the L fund glide path to your own allocation before going manual.

Recheck your catch-up election each December. The age-60-to-63 window changes your catch-up limit automatically, but the SECURE 2.0 Roth rule depends on your prior-year wages, which you can only know after the year closes. If your 2025 wages crossed $150,000, plan for your 2026 catch-up to be Roth from the start.

Roll old TSP balances together, or roll the TSP into your IRA. If you change agencies, your TSP follows you. If you leave federal service, you can leave the money in the TSP, roll it into an IRA, or roll it to a new employer's plan. Leaving it in the TSP preserves the plan's rock-bottom fees; the Roth IRA Contribution & Growth Calculator shows what the same money could do with complete investment freedom.

Limitations

This calculator is a planning tool, not a statement from the TSP. It assumes a constant annual return equal to the fund's 10-year average (or your override), which real markets never deliver — sequence-of-returns risk can make your actual balance far higher or lower depending on when the bad years land. The match is modeled correctly for FERS and BRS, but uniformed services pay can include tax-exempt allowances that follow different contribution rules, and agency-specific bonuses are not modeled. The projection also ignores inflation in its default setting: a $527,000 balance in 2046 buys less than it does today, so consider using the return override to work in real terms.

The limits mode reflects 2026 law but cannot know your personal situation: it uses your age for the catch-up tiers, your pay frequency for the per-paycheck target, and your prior-year wages for the Roth rule, but it does not account for contributions made to another employer's plan during the year or for contributions from tax-exempt pay in a combat zone. The 60-63 higher catch-up applies in the calendar year you turn those ages, and the calculator uses the age you enter. When in doubt, confirm the exact figures with your payroll office or the TSP before the last pay period of the year.

Frequently Asked Questions

❓ How does the TSP agency match work?

✅ Your agency contributes 1% of your pay automatically (after vesting), then matches your own contributions dollar-for-dollar on the first 3% of pay and 50 cents on the dollar for the next 2%. At a 5% employee contribution you receive a total agency contribution of 5% of pay.

❓ Is the TSP match the same for BRS employees?

✅ Yes. BRS (Blended Retirement System) participants receive the same 1% automatic plus up to 4% matching as FERS employees. The main difference is that BRS automatic contributions vest after only 60 days of service instead of the three-year FERS schedule.

❓ Do CSRS employees get the TSP match?

✅ No. Employees under the Civil Service Retirement System receive no agency automatic or matching contributions to the TSP. They may still contribute their own money up to the elective deferral limit.

❓ What is the TSP contribution limit for 2026?

✅ The elective deferral limit is $24,500. Participants turning 50-59 or 64+ in 2026 may add an $8,000 catch-up, and participants turning 60-63 may add an $11,250 catch-up. Employee plus agency contributions combined are capped at $72,000.

❓ Why must my 2026 catch-up be Roth?

✅ SECURE 2.0 requires participants with prior-year wages over $150,000 from TSP-eligible positions to make catch-up contributions to the Roth TSP balance. Below that threshold, catch-ups can still go to the traditional balance.

❓ How much should I contribute to the TSP?

✅ At minimum, contribute 5% of pay to capture the full federal match. That gives you a 10% total savings rate for only a 5% personal cost. For most federal employees the recommended total savings rate, including the match, is 10-15% of pay.

❓ Which TSP fund should I choose?

✅ Most federal employees are well served by a Lifecycle fund matching their expected retirement year. L funds are automatically diversified and rebalanced. If you prefer individual funds, the C and S Funds historically offered the highest long-term growth, with higher volatility than G or F.

❓ Does the calculator account for the G Fund's low returns?

✅ Yes. Each fund's default projection rate is its actual 10-year average return, so the G Fund projects at 2.92% while the C Fund projects at 15.05%. You can override any fund with your own expected return.

❓ What happens to my TSP when I leave federal service?

✅ You can leave it in the TSP, roll it to your new employer's plan, or roll it into an IRA. Leaving it preserves the TSP's very low fees. Note the vesting rule: if you leave before three years of FERS service, you forfeit the unvested automatic 1% contributions.

❓ Can I contribute to the TSP and an IRA in the same year?

✅ Yes. The TSP and IRA limits are independent. You can make the full $24,500 TSP deferral and the full $7,500 IRA contribution in 2026. The main interaction is that TSP contributions do not reduce your IRA limit, but Roth IRA eligibility depends on your modified adjusted gross income.