TSP Calculator

2026 TSP Contribution Limits

The IRC § 402(g) elective deferral limit for 2026 is $24,500. This is the amount of your own pay you can defer into TSP — it does not include the BRS match from DoD. Two catch-up contributions sit on top of the standard limit:

• Age 50 and over: An additional $8,000 per year. The amount is published alongside the elective deferral limit each November via the IRS annual cost-of-living adjustment notice.
• Ages 60 through 63 (SECURE 2.0 super catch-up): An enhanced catch-up contribution of $11,250 per year — equal to the greater of $10,000 or 150% of the standard age-50 catch-up, indexed for inflation. Reverts to the regular catch-up at age 64.

The 402(g) limit is shared. A reservist or Guard member with a civilian 401(k) or 403(b) cannot max both — the limit applies to the combined total of all elective deferrals into qualified plans for the same tax year. The calculator surfaces this fact near the contribution input so users don't assume two separate limits.

Tax-free combat-zone pay (CZTE) you contribute to Traditional TSP does not count against the 402(g) limit, but it does count against the higher annual additions limit (which includes employer contributions). CZTE pay contributed to Roth TSP still counts against 402(g) — but Roth-CZTE is the rare double-tax-free scenario (tax-free in, tax-free out), which makes it powerful during deployment despite the cap.

BRS Matching: How the 5% Government Contribution Works

If you joined service on or after January 1, 2018, you're in the Blended Retirement System (BRS). Service members who joined before that date and opted in are also under BRS. Under BRS, the Department of Defense contributes to your TSP regardless of your own participation:

• Automatic 1%: DoD contributes 1% of your basic pay whether you contribute or not.
• Dollar-for-dollar match on the next 3%: If you contribute 3%, DoD matches 3%.
• Fifty cents on the dollar for the next 2%: Contributing 4% gets you a 0.5% additional match; contributing 5% gets you the full additional 1%.

Bottom line: contribute at least 5% of basic pay to capture the full 5% government contribution. Anything less is leaving free money on the table. Government matching contributions vest after two years of service. The calculator above models this schedule end-to-end — adjust your contribution percent and watch the DoD contribution figure update in real time.

Legacy retirement system: Service members who joined before 2018 and did not opt in to BRS are under the Legacy "High-3" retirement system, which pays 2.5% of base pay per year of service at the 20-year mark, with no DoD TSP contributions. Toggle off "Blended Retirement" in the calculator to model this scenario.

Roth TSP vs Traditional TSP

TSP supports both Roth (after-tax) and Traditional (pre-tax) contributions. You can split your contribution between the two. The right choice depends primarily on your current and expected future tax brackets:

• Roth TSP makes sense when you're in a low tax bracket today and expect to be in a higher bracket in retirement — typical for junior enlisted, junior officers, and service members in a combat zone (since combat-zone pay is already tax-free, Roth contributions during deployment grow with effectively no tax friction).
• Traditional TSP makes sense when you're in a high tax bracket today and expect to be lower in retirement — typical for senior officers and dual-income households at the high end of the military pay scale.
• The honest answer for most service members: Split between the two if you're unsure. The tax diversification gives you flexibility to optimize withdrawals decades from now.

Choosing Your Fund Allocation

TSP offers five core funds plus a series of Lifecycle (L) Funds. The calculator above uses trailing 10-year returns captured 2026-05-06 from official monthly TSP fund returns. The core funds:

• G Fund — non-marketable U.S. Treasury securities; principal protection, low return (2.8% 10-year average).
• F Fund — broad U.S. investment-grade bond index (1.7% 10-year average).
• C Fund — tracks the S&P 500 (large-cap U.S. stocks; 15.4% 10-year average).
• S Fund — small and mid-cap U.S. stocks (Dow Jones U.S. Completion TSM; 12.2% 10-year average).
• I Fund — international developed-markets stocks (10.2% 10-year average).
• L Funds — pre-mixed allocations of the above five funds, rebalanced quarterly toward more conservative holdings as the target year approaches.

For most service members, the L Fund matched to your expected retirement year is the right default. Pick L 2065 or L 2070 if you're early career; L 2050 or L 2055 mid-career; L Income at and after retirement. The L Funds handle rebalancing, which is the single most-skipped task for self-directed TSP investors.

If you're comfortable picking individual funds, the most common long-horizon allocation for early-career service members is heavy in C and S Funds with a smaller I Fund slice. The G Fund is a parking spot for capital you want protected, not a long-term growth holding — over decades it consistently underperforms the equity funds by enough to materially change retirement outcomes. Past performance does not predict future returns; the calculator's projections are planning estimates, not forecasts.

TSP Loans and Withdrawals

TSP offers two loan types: general purpose (up to five-year term) and primary residence (up to fifteen-year term). The interest you pay on either goes back into your own account at the G Fund rate set at loan origination. Two trade-offs to understand:

• The dollars you borrow are pulled out of their current investments. While the loan is outstanding those dollars are not earning market returns — they're only earning the G Fund rate via your repayments.
• If you separate from service with an outstanding loan, you have a limited window to repay before the IRS treats the unpaid balance as an early withdrawal — triggering income tax plus a 10% penalty if you're under 59½.

At separation or retirement you can leave the balance in TSP (often the cheapest option given TSP's very low expense ratios), roll to a civilian 401(k) or IRA, or take partial or full withdrawals. Always compare TSP's expense ratios against any rollover destination before moving funds — many civilian providers charge orders of magnitude more.

How This Calculator Models Your TSP

The calculator above uses official TSP fund historical returns (trailing 10-year window through 2026-05-06) to model compound growth under your specified contribution rate, fund mix, and time horizon. It models the BRS 5% government contribution end-to-end if you indicate active duty. The 402(g) limit is enforced in the model so you can see whether your contribution percent exceeds the IRS ceiling at your current paygrade. It does not promise specific future returns — past performance does not predict future returns — but it gives you a credible model anchored in real published data rather than arbitrary assumptions.

Related Garrison Ledger Tools

TSP doesn't live in a vacuum. A few related tools that show up in the same financial decisions:

• SDP Strategist — The Savings Deposit Program offers a 10% guaranteed annual return on up to $10,000 during deployment. Often higher priority than TSP contributions during a combat-zone tour.
• Salary Calculator — Compare total military compensation against civilian offers, including TSP-vs-401(k) match value and BRS pension present value.
• House Hacking Calculator — Use BAH and a VA loan to acquire a multi-unit property as part of a broader retirement strategy beyond TSP.
• Ask the Military Expert — Five free questions a month with citations from the JTR, DFAS rules, and TSP.gov. Useful for the "but in my specific situation..." follow-ups this guide can't cover.
• Monthly Military Financial Briefing — One email a month covering rate releases, contribution-limit updates, and JTR changes for military families.

Sources

TSP.gov contribution limits · IRS Notice 2025-67 · TSP Bulletin 25-3 (2026 contribution limits) · TSP fund options and historical returns · DoD Blended Retirement System · DFAS pay tables · IRS Publication 3 (Armed Forces Tax Guide)