TSP for Beginners: What Happens If You Never Change Your Settings

Under BRS, the military automatically enrolls new members in TSP at 5% of basic pay, invested in an age-appropriate Lifecycle fund — a reasonable default that most members never examine. The government adds a 1% automatic contribution after 60 days and begins matching contributions up to 5% of base pay after two years of service, so contributing less than 5% means leaving part of that match on the table every month. The most consequential decision is fund allocation: an account sitting in the G Fund can produce significantly lower long-term growth than one diversified into stock funds, and the compounding difference over a 20-year career can reach hundreds of thousands of dollars.

If you never log into TSP — what's actually happening

When you entered the military under BRS, someone set up a TSP account for you. They enrolled you at 5% of base pay. They picked a fund based on your expected retirement year. Then, for many service members, nothing changes — ever.

That's not automatically a disaster. The default settings under BRS — 5% contribution into an age-appropriate Lifecycle Fund — are a meaningful improvement over older TSP defaults, which defaulted contributions to the G Fund. But "a reasonable starting point" and "optimal for your situation" are not the same thing, and the gap between them compounds over decades.

Here's what your TSP account is doing right now — whether you've ever logged in or not.

What happened when you enrolled

Under the Blended Retirement System (BRS), the military automatically enrolls new service members in TSP at 5% of basic pay, beginning 60 days after entry into service.

Your contributions generally go into the Lifecycle Fund closest to your expected retirement year. A young service member may be placed in one of the far-dated L Funds, such as L 2065 or L 2070, depending on age and current TSP fund availability.

At the same time, the government starts contributing:

• 1% automatic contribution — begins 60 days after entry, regardless of whether you contribute anything
• Government matching contributions — generally begin after two years of service for BRS members who began service on or after January 1, 2018, matching 100% of your first 3% and 50% of your next 2% (up to 5% total)

This means: once matching eligibility begins (after two years of service), if you contribute 5% of base pay, the government adds another 4% in matching, plus the 1% automatic contribution — totaling 5% from the government. Your 5% effectively becomes 10% going into TSP.

That's a 100% return on the first 3% you contribute before the money is ever invested — once the match kicks in. In your first two years, you still receive the 1% automatic contribution, but not the matching. Ignoring the match once you're eligible is the most expensive TSP mistake there is.

Older accounts: Older TSP accounts may have been defaulted into the G Fund, depending on when and how the account was opened. If you joined before BRS, opted into BRS during the transition window, or have never reviewed your allocation, log in to TSP.gov and verify where both your existing balance and future contributions are going.

What the G Fund actually does (and doesn't do)

The G Fund invests in special-issue U.S. Treasury securities — a type of debt backed by the full faith and credit of the U.S. government. It has never lost value in any single month since TSP began in 1987.

That sounds like exactly what you want. And if you're five years from retirement, it might be. But if you're 24 years old with 30+ years of compounding ahead of you, the G Fund has a serious problem: it barely keeps up with inflation.

The G Fund's historical returns have varied with the interest rate environment — check TSP.gov's fund performance page for current and historical data. Long-run inflation averages roughly 3% per year. In periods where the G Fund return is close to or below the inflation rate, the real (inflation-adjusted) purchasing power of G Fund money grows slowly or not at all.

What this means over 20 years:

An E-4 contributing $150/month starting at age 20 for 20 years (contributions would increase with base pay — this is a simplified illustration):

These are simplified projections for illustration. Actual returns will vary. Past performance does not guarantee future results. The point is not the specific numbers — it's the direction and magnitude of the gap.

By age 60 (after 40 years of compounding), the difference between a G Fund approach and a diversified stock allocation started at age 20 can exceed several hundred thousand dollars — from the same contribution amounts.

The G Fund's safety matters. But safety has a price, and for young investors with decades to go, that price is paid in compound growth you never received.

What the L Funds actually do

Lifecycle Funds are the BRS default, and they're a genuine improvement over a G Fund default.

An L Fund holds a mix of all five core TSP funds (C, S, I, F, and G). When you're young and far from your target date, the L Fund is heavily weighted toward stock funds (C, S, and I) — the exact allocation varies by L Fund and shifts over time as TSP adjusts the glide path. As your target date approaches, the fund automatically shifts toward more conservative investments (F and G Funds). Check TSP.gov for the current allocation breakdown of your specific L Fund.

The logic is called a glide path: take more risk when you have time to recover from downturns, reduce risk as you need the money.

What the L Fund is:

• A reasonable starting point
• Self-rebalancing (you don't have to do anything)
• Properly diversified across the asset classes available in TSP

What the L Fund isn't:

• The highest-growth option at any age
• A substitute for understanding your own risk tolerance
• Guaranteed to be optimal for your specific situation

Many service members do fine with the L Fund their entire career. Others prefer to build their own allocation with more C and S Fund exposure. Neither is universally correct — it depends on your timeline, your comfort with volatility, and how engaged you want to be.

The BRS match: free money with an expiration date

If you're a BRS member contributing less than 5%, you're not capturing the full government match. Let's be specific about what you're leaving behind.

BRS government contributions:

The match on your first 3% is dollar-for-dollar. The match on the 4th and 5th percent is $0.50 on the dollar. Contributing more than 5% doesn't increase the match — the government contribution is capped at 5% total.

For an E-5 earning $3,947/month in base pay (2026), the full government match represents approximately $197/month in free contributions. Over a 20-year career at that match level, that's roughly $47,000 in government contributions alone — before any investment growth on those funds.

Vesting note: The 1% automatic contribution vests after 2 years of service. Government matching contributions vest immediately. If you separate before 2 years, you may forfeit the 1% automatic contributions.

Roth TSP vs. Traditional TSP

You have two tax treatment options for your TSP contributions:

Traditional TSP:

• Contributions reduce your taxable income now
• Money grows tax-deferred
• Withdrawals in retirement are taxed as ordinary income
• Makes sense if you expect to be in a lower tax bracket in retirement than you are now

Roth TSP:

• Contributions are made from after-tax income (no current tax deduction)
• Money grows tax-free
• Qualified withdrawals in retirement are completely tax-free
• Makes sense if you expect your tax bracket to be higher in retirement, or if you're currently in a low tax bracket

For most junior enlisted members, Roth is worth considering seriously. At E-1 through E-4 pay grades, federal income tax rates are low — often 10–12%. That's a low price to pay now for completely tax-free withdrawals decades from now, when you may be in a higher bracket.

During a combat zone deployment, Roth TSP contributions become even more powerful. Pay earned during CZTE-qualifying months is already excluded from federal income tax — contributing that tax-exempt pay to Roth TSP means the money was never taxed going in and qualified withdrawals will never be taxed.

Combat-zone TSP rules can create extra contribution room, but the details matter. Roth TSP contributions still count toward the regular elective deferral limit ($24,500 in 2026). The extra room above that limit generally comes from traditional contributions made from tax-exempt combat-zone pay, which do not count against the elective deferral limit but do count toward the annual additions limit. If you are trying to contribute beyond the normal annual limit during deployment, verify the rules through TSP.gov and your finance office before changing elections. See The Roth TSP Deployment Strategy That Builds a Tax-Free Fortune for the compound growth math on this.

Consider your situation — current tax bracket, expected retirement income, spouse's income, state taxes — before deciding. Neither Roth nor Traditional is universally better. The government match always goes into Traditional TSP regardless of your election.

How to check and change your settings

Two different systems handle two different parts of TSP. This confuses many service members.

To change your contribution percentage or Roth/Traditional election: → Log in to myPay (mypay.dfas.mil) → Navigate to TSP Contribution Elections → Change your percentage and/or your designation (Roth vs. Traditional) → Changes typically take 1–2 pay periods to take effect

To change your fund allocation (which funds your money goes into): → Log in to TSP.gov → Create an account if you haven't (you'll need your SSN and other identifying info) → Navigate to Investment > Fund Transfers and Contribution Allocations → Set your new allocation percentages

Note: Changing your allocation on TSP.gov changes how new contributions are invested. It does not automatically move your existing balance. To move your existing balance to a different allocation, you need a "fund transfer" (also called an "interfund transfer") on TSP.gov. Both steps may be needed to fully update your allocation.

The five TSP funds — 30-second version

G Fund: U.S. government securities. Lowest risk and return. Never loses value. Earns roughly the short-term Treasury rate. Suitable for money you can't afford to lose or money you'll need soon.

F Fund: Bond index (Bloomberg Barclays U.S. Aggregate Bond Index). Slightly more return potential than G, slightly more risk. Bonds can lose value in rising interest rate environments.

C Fund: S&P 500 index. Tracks 500 large U.S. companies. The long-run workhorse of TSP. Historically returns around 10–11% per year averaged over long periods — but individual years can look dramatically different (the C Fund lost roughly 38% in 2008 and roughly 18% in 2022). The historical average is real, but only captures value for investors who stay invested through downturns rather than selling in response to them. Long-term averages are not a promise — they are only useful if the investor stays invested through major drawdowns. Past performance does not guarantee future results.

S Fund: Small and mid-cap U.S. stock index. Higher growth potential than C Fund over long horizons, more volatile. Good complement to the C Fund.

I Fund: International stock index. Diversification outside the U.S. economy. Historically lower U.S. dollar returns than C Fund but provides geographic diversification.

L Funds: Lifecycle blends of all five funds, automatically adjusted based on your target date. L Income is most conservative (for those already in or near retirement). L 2070 is most aggressive (for those with the longest time horizon).

For a full breakdown of each fund's structure, historical returns, and expense ratios, see TSP Fund Options Explained.

What to do right now, based on where you are

If you just started service:

1. Verify you're enrolled at 5% to capture the full BRS match
2. Log in to TSP.gov and check your fund allocation — make sure you're not sitting 100% in the G Fund
3. Consider Roth contributions while you're in a low tax bracket
4. Set a reminder to check your TSP once a year — it doesn't need daily attention

If you're mid-career (6–14 years):

1. Review your allocation — make sure it reflects your actual risk tolerance, not a forgotten default
2. Consider increasing your contribution rate above 5% if your budget allows — the annual limit is $24,500 in 2026
3. Review Roth vs. Traditional: if you expect a high retirement income (pension + TSP + Social Security), Traditional may reduce your lifetime tax burden
4. If you've deployed and didn't maximize contributions, look at future deployment windows

If you're approaching separation or retirement (15–20 years):

1. Verify your allocation is shifting appropriately toward your timeline
2. Understand your options post-separation: you can leave money in TSP indefinitely — TSP is among the lowest-cost workplace retirement plans available (verify current expense ratio at tsp.gov)
3. Understand required minimum distribution rules and post-separation withdrawal options
4. Consider how your TSP fits with your pension and other retirement income

The one-paragraph version

Contribute at least 5% of your base pay to TSP so you capture the full government match. Log in to TSP.gov and verify you're not 100% in the G Fund if you have more than 10 years until retirement. Consider Roth if you're a junior enlisted member in a low tax bracket. If you're deploying to a combat zone, review your Roth TSP election before you leave. Tax-exempt combat pay can make Roth contributions especially valuable, but contribution-limit rules get more complicated if you try to go above the normal annual limit. Check your settings once a year — it takes 10 minutes. That's it. Everything else is optimization from there.

The TSP Growth Projector lets you model your specific contribution rate, allocation, and timeline. The Total Compensation Calculator shows where your TSP match fits in your full pay picture. Both are free and take 2 minutes. For a plain-English breakdown of what each TSP fund actually does, see TSP Fund Options Explained. For what happens to your TSP balance when you leave the military, see What Happens to Your TSP When You Leave the Military?.

Projected returns in this post are illustrative based on historical averages and simplified assumptions. Actual returns will vary. Past performance does not guarantee future results. TSP expense ratios, contribution limits, and government match rules are based on 2026 figures — verify current limits at tsp.gov.