Military Retirement Calculator: Estimate Pension and TSP Income
Use this guide to understand the assumptions, inputs, results, and next steps behind the calculator.
Created by Luis Gonzalez · Last updated July 25, 2026
Military retirement income can include a service pension and withdrawals from the Thrift Savings Plan (TSP). This calculator estimates retired pay under a selected system, models a fixed-term monthly TSP withdrawal, combines the two income sources, and compares the total with pre-retirement salary.
With the default High-3-style assumptions, it estimates $3,750 monthly retired pay, $1,499 monthly TSP income, and $5,249 total monthly income. The modeled replacement rate is 70% of the entered $90,000 annual salary. These results are estimates, not an official retirement calculation or guaranteed TSP income.
Enter Your Pay, System, and Savings
Enter monthly base pay, years of service, retirement system, TSP balance, expected TSP return, COLA, years in retirement, inflation, and pre-retirement salary. The system selection affects the pension multiplier. The calculator uses 2.5% per year for its High-3 option and 2.0% for its other system choices; its Redux option also adds a modeled $30,000 bonus.
The defaults are $7,500 monthly base pay, 20 years of service, High-3 selected, $250,000 TSP balance, 6% TSP return, 2.5% COLA, and 30 years of retirement. The model estimates the pension first and then calculates a monthly TSP draw over the selected 30-year period.
To focus on the pension calculation, compare the Military High-3 Calculator or Military Pension Calculator. For a separate estimate of the Redux bonus and COLA comparison, use the Military Redux Retirement Calculator.
Default Results, Step by Step
At 20 years of service, the High-3-style multiplier is 20 × 2.5% = 50%. The pension estimate is $7,500 × 50% = $3,750 per month, or $3,750 × 12 = $45,000 annually.
For the TSP estimate, the calculator uses a 6% annual return converted to a monthly rate and spreads withdrawals over 360 months. Its result is $1,499 per month, or $1,499 × 12 = $17,988 annually. Combined, $3,750 + $1,499 = $5,249 monthly, and $5,249 × 12 = $62,988 annually.
The replacement rate is $62,988 ÷ $90,000 = 69.99%, rounded to 70%. It compares estimated annual pension plus TSP income with the entered salary. It does not compare income with spending, and it does not include Social Security, taxes, healthcare, or other household income.
| Retirement system modeled | Years of service | Pension multiplier | Monthly pension | TSP income | Combined monthly estimate |
|---|---|---|---|---|---|
| High-3 | 20 | 50% | $3,750 | $1,499 | $5,249 |
| 2.0% system (BRS-style estimate) | 20 | 40% | $3,000 | $1,499 | $4,499 |
| Redux option in calculator | 24 | 48% | $3,600 | $1,499 | $5,099 |
The table uses the calculator’s formulas, keeps the $250,000 TSP balance and withdrawal assumptions fixed, and changes the selected system or service years. The Redux row includes a $30,000 bonus in the model, but the table’s monthly total does not convert that bonus into a monthly income stream.
Pension Formula and System Differences
The calculator uses a 2.5% multiplier per service year for High-3 and 2.0% per year for its other system choices, with a 75% cap. BRS uses a 2.0% pension multiplier alongside TSP contributions and matching; it is not the same as the historical Redux election. The Redux option has distinct bonus and COLA assumptions. Confirm your actual system before relying on a multiplier. See the Department of Defense BRS information.
The default multiplier is 20 × 2.5% = 50%. Applied to $7,500 base pay, that gives $3,750 monthly. The calculator does not project a High-36 average from monthly pay records; it applies the selected percentage directly to the entered base pay. For an estimate that emphasizes High-3 pay history, use the Military High-3 Calculator.
The calculator’s TSP withdrawal is a mathematical payout over the chosen number of months, assuming a steady monthly return. It is not a guaranteed annuity and does not account for volatile returns, changing withdrawals, fees, taxes, or a TSP annuity purchase. A fixed 30-year draw also does not necessarily last for the retiree’s lifetime.
Formula and What the Outputs Mean
The pension formula applies a service multiplier, while the TSP formula estimates a fixed payment that amortizes a balance over the selected months at the assumed return.
Pension multiplier = lesser of (service years × system rate) or 75%
Monthly retired pay = monthly base pay × pension multiplier
Monthly TSP income = TSP balance × monthly return
÷ [1 − (1 + monthly return)^(-number of months)]
Total monthly income = monthly retired pay + monthly TSP income
Replacement rate = (total monthly income × 12) ÷ pre-retirement annual salary
Real midpoint income = total monthly income ÷ (1 + inflation rate)^(years in retirement ÷ 2)
For the default case, the pension multiplier is 50%; $7,500 × 0.50 = $3,750. The TSP estimate is $1,499 monthly. Total monthly income is $3,750 + $1,499 = $5,249. Annual income is $5,249 × 12 = $62,988, and $62,988 ÷ $90,000 = 70% after rounding.
The calculator’s midpoint real-income estimate is $3,624 per month after applying 2.5% inflation halfway through the 30-year period. It also estimates $1,975,621 in lifetime retired pay, with the final year’s annual pension projected at $92,088. The TSP stream and pension lifetime total are modeled separately; do not treat the pension lifetime figure as combined lifetime income.
Questions About Military Retirement Income
Is the TSP monthly amount guaranteed for life?
No. It is an amortization estimate over the selected number of years and assumes a steady return. Actual investment performance and withdrawals vary, and the estimate is not a lifetime annuity.
Does 20 years always produce a 50% pension?
No. The calculator’s High-3-style setting uses 2.5% per service year, which yields 50% at 20 years. BRS generally uses 2.0% per year, while other rules may apply. Confirm the retirement system and service record.
Does the replacement rate mean I can maintain my current lifestyle?
No. It compares modeled pension-plus-TSP income with entered salary. Salary is not the same as take-home pay or retirement spending, and the calculation omits taxes, healthcare, Social Security, and other income.
Should I choose a longer TSP withdrawal period or a shorter one?
A longer period generally lowers the estimated monthly draw but spreads the balance across more months. A shorter period raises the modeled monthly amount and increases the risk that funds are exhausted sooner. The right duration depends on other income, investment risk, and longevity.
Does the Redux bonus count as monthly income here?
No. The calculator identifies a Redux bonus but does not add it to the monthly income card. The bonus is a separate lump sum and should be evaluated for taxes, investment risk, and spending plans.
Are COLA increases guaranteed at 2.5%?
No. The 2.5% input is an assumption. The calculator uses it to project pension growth; actual adjustments can differ. Check official military pay updates for current benefit rules.
How should I plan taxes on the pension and TSP withdrawals?
This calculator does not estimate tax withholding. Pension and TSP distributions may be taxed differently depending on the situation. Read how 401(k) withdrawals are taxed in retirement and use the Tax-Efficient Retirement Withdrawal Calculator for separate planning.
Next Steps to Build a Complete Retirement Picture
Test different service years, TSP balances, returns, and withdrawal durations. Compare pension-only estimates with the Military Disability Retirement Calculator and the Military SBP Calculator if survivor protection may affect the plan.
Then compare income with projected spending using the Retirement Needs Calculator and Retirement Number Calculator. Estimate withdrawal choices with the Retirement Withdrawal Strategy Calculator, and review the best order to withdraw from retirement accounts. Replace assumptions with official pay and account data before making a retirement decision.