RETIREMENT · FEDERAL EMPLOYEES

TSP Calculator

Project your Thrift Savings Plan (TSP) balance across all five funds — G, F, C, S, and I. See how your fund allocation and contribution rate affect your retirement nest egg.

LAST REVIEWED · APR 08, 2026 · BY A. CHEN, CFP®
You need
$1,057,488
Est. cost
$155,473
TSP DetailsReset
Current balance
$50,000
$0$2M
Annual salary
$80,000
$20K$250K
Contribution rateOf salary
10%
0%100%
Years to grow
25 yrs
140
Fund Allocation
G FundGovt securities ~2.5%
10%
0%100%
F FundBonds ~3.5%
10%
0%100%
C FundS&P 500 ~10%
40%
0%100%
S FundSmall/mid ~10.5%
20%
0%100%
I FundInternational ~7%
20%
0%100%

How the TSP calculator works

The Thrift Savings Plan offers five core funds, each tracking a different index. This calculator projects your balance in each fund based on historical average returns, your contribution rate, and your fund allocation.

The five TSP funds

  • G Fund — Government securities (~2.5% avg). Lowest risk, guaranteed principal.
  • F Fund — Bond index (~3.5% avg). Low risk, tracks Bloomberg Barclays U.S. Aggregate.
  • C Fund — S&P 500 index (~10% avg). Core large-cap equity exposure.
  • S Fund — Small/mid-cap index (~10.5% avg). Higher growth potential, more volatility.
  • I Fund — International index (~7% avg). Developed market diversification.

Lifecycle (L) funds

If you’re not sure how to allocate, TSP’s Lifecycle funds automatically shift from stocks to bonds as you approach retirement. This calculator models individual fund choices for more granular control.

Methodology. Projects each fund’s balance independently using historical average returns: G Fund (2.5%), F Fund (3.5%), C Fund (10%), S Fund (10.5%), I Fund (7%). Contributions allocated proportionally to the selected fund allocation. Annual compounding applied per fund.

Sources

  • TSP.gov — Fund Performance and Historical Returns
  • Federal Retirement Thrift Investment Board annual reports
  • TSP contribution limits for 2026: $23,500 ($31,000 catch-up for 50+)
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Frequently asked questions

What’s the best TSP fund allocation? +
There’s no universal best. A common aggressive allocation is 60% C, 20% S, 20% I. A moderate one is 40% C, 15% S, 15% I, 20% F, 10% G. Your ideal mix depends on your age and risk tolerance.
Should I use the G Fund? +
The G Fund guarantees your principal but barely keeps up with inflation. It’s appropriate for money you’ll need in the next 1–3 years, but holding too much in G over decades significantly reduces growth.
Does the TSP match contributions? +
FERS employees receive an automatic 1% agency contribution plus a match of up to 4% (dollar-for-dollar on the first 3%, 50 cents per dollar on the next 2%). Contribute at least 5% to get the full match.