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TSP Calculator

Estimate how your TSP contributions, FERS agency contributions and investment growth could add up by retirement.

Your numbers

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Result

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Verify before you act: review these results with a fiduciary financial planner and, for tax questions, a CPA before making any decision based on them.

What is a TSP calculator?

A TSP calculator estimates how your Thrift Savings Plan balance could grow over time. It combines your current balance, your contributions, agency contributions when applicable, and estimated investment growth.

For FERS employees, the agency contribution formula includes an automatic contribution of 1% of basic pay. The agency also matches your first 3% dollar for dollar and the next 2% at 50 cents per dollar. The match is based on your eligible contributions and pay.

Why your TSP projection matters

A projection can help you see whether your current savings pace supports the retirement you are planning for. It can also show how much of your projected balance comes from your contributions, agency contributions and investment growth.

Use the estimate to compare choices, such as raising your contribution, changing your planned retirement age, or keeping more money in your TSP when you change jobs. If you are a FERS employee, contributing enough to receive the full available match can add agency money to your retirement savings. The calculator is a planning aid, not a promise of future returns or a recommendation about investments.

The calculator applies the FERS agency contribution formula. If you are not covered by FERS, or your circumstances differ from the assumptions, your agency contributions may not match the estimate. Confirm your plan details with a qualified financial professional.

How to use this TSP calculator

  1. Enter your current age and the age you expect to retire. The difference sets the projection period.
  2. Enter your basic pay and current TSP balance. Use your current balance across your TSP accounts if the calculator asks for one combined figure.
  3. Enter your contribution as a percentage of basic pay. For a FERS employee, the calculator uses the agency automatic and matching contribution formula.
  4. Enter your expected yearly raise and annual investment return. These are assumptions, not guarantees. Try a lower return as a cautious comparison.
  5. Review the projected balance and its components. The fields labeled Match and Match cap are not used by this calculator, so changing them will not change the estimate.

TSP calculator example

Worked example

With a current age of 35, retirement age of 60, basic pay of $80,000, current TSP balance of $30,000, a 5% contribution, a 2.5% yearly raise and a 6.5% annual return, the sample projection is $758,911 at age 60. It shows $136,631 from you, $136,631 from the agency and $455,649 in investment growth. The result label says “401(k) balance at 60”; for this calculator, read that as the projected TSP balance. The projection assumes the stated pay, contribution and return assumptions continue as entered.

How to read your TSP calculator results

Your contributions are the estimated money you put into the plan over the projection period. Agency automatic and matching contributions show the estimated amount added under the FERS formula. Investment growth is the estimated increase from returns on the invested balance and contributions.

Projected balance combines those components with your starting TSP balance. It is an estimate in future dollars, so it does not show what that money may buy after inflation. A different return, raise, contribution rate or retirement age can change the result substantially. Compare scenarios rather than treating one result as certain.

How to improve your TSP outlook

  1. 01

    Raise your contribution when your budget allows

    Consider increasing your contribution by one percentage point after a pay raise or when a recurring expense ends. Recheck your budget and the calculator to see how the change affects the projection.

  2. 02

    Capture the available FERS match

    If you are covered by FERS, check your payroll election and TSP statement to confirm you contribute enough to receive the full matching contribution available under the formula. The automatic 1% contribution is separate from your own contribution.

  3. 03

    Test a later retirement age

    Compare your planned retirement age with a later option. Continuing contributions for longer can add savings, though your personal plans and other income sources matter too.

  4. 04

    Use cautious assumptions

    Run the estimate with a lower annual return or a smaller yearly raise as a comparison. This helps you see whether your plan depends on optimistic assumptions.

  5. 05

    Check your contribution limit

    The listed 2026 employee contribution limit is $24,500. The listed catch-up amounts are $8,000 for age 50 and older and $11,250 for ages 60–63. Review current TSP and IRS rules before changing payroll contributions, since eligibility and limits can affect your plan.

Common TSP calculator mistakes

  • Treating the projection as guaranteed

    The annual return is an input, not a promised result. Investment values can rise or fall, so compare more than one assumption.

  • Entering the wrong contribution rate

    The contribution field is a percentage of basic pay. Check your payroll election so the estimate reflects what you actually contribute.

  • Counting agency contributions as your own

    The agency amount is separate from your contribution. Review both lines to understand how much comes from each source.

  • Assuming the estimate fits every TSP participant

    This calculator uses the FERS agency formula. Do not assume the agency estimate applies to you if your service or plan rules differ.

The TSP formula

FERS agencies contribute 1% automatically, match your first 3% dollar for dollar and the next 2% at 50 cents per dollar, for up to 5% total.

Key terms

TSP
The Thrift Savings Plan, a retirement savings plan for eligible federal employees and service members.
FERS
The Federal Employees Retirement System. The agency contribution formula in this calculator is for FERS employees.
Basic pay
The pay amount used in the calculator to estimate your contributions and FERS agency contributions.
Agency automatic contribution
The FERS agency contribution of 1% of basic pay, separate from matching contributions.
Matching contribution
Agency money added based on your eligible contributions under the FERS formula.

TSP questions

How much does FERS contribute to my TSP?

The agency contributes 1% of basic pay automatically, matches your first 3% dollar for dollar, and matches the next 2% at 50 cents per dollar. The maximum agency contribution under this formula is 5% of basic pay when you contribute at least 5%.

Does this calculator use the Match and Match cap fields?

No. Both fields are marked not used. The calculator applies its built-in FERS automatic and matching contribution formula instead.

Is my projected TSP balance guaranteed?

No. It is an estimate based on the inputs you provide, including the annual return and yearly raise. Actual investment performance, contributions and future rules may differ.

What is the 2026 TSP contribution limit?

The listed 2026 employee contribution limit is $24,500. Listed catch-up amounts are $8,000 for age 50 and older and $11,250 for ages 60–63. Confirm current eligibility and rules with the TSP or a qualified financial professional.

Sources

Before you act on this result. Cordwell calculators and guides are educational estimates, not legal, tax, investment, lending or other professional advice. They rely on the numbers you enter and on simplified rules, and they can't see your full situation. Before you file, sign, borrow, invest, hire, change your withholding or form a business based on anything here, meet with a fiduciary financial planner and, for tax questions, a CPA who can review your specific facts and confirm the numbers. Rules change, and official agency guidance always controls.

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