Military Retirement Pay Calculator — How to Estimate Your Pension

The Two Retirement Systems — BRS vs High-3

Military retirement has gotten complicated with all the misinformation flying around. I spent fourteen years assuming my retirement would work one way — then found out at year eighteen that the rules had fundamentally shifted under my boots. That was a rough Tuesday.

Here’s what every service member needs to know upfront: if you entered before January 1, 2018, you’re under the legacy High-3 system. Join after that date, and you’re automatically in the Blended Retirement System, or BRS. That single distinction determines whether your monthly pension check reads $2,500 or $3,200 when you’re 42 years old and suddenly a civilian again.

But what is the High-3 system, exactly? In essence, it’s a pension formula that pays you 50% of your highest 36 months of average base pay after 20 years of service. But it’s much more than that — it rewards staying in. Every additional year beyond 20 tacks on another 2.5%. Serve 21 years and you’re at 52.5%. Hit 25 years and that climbs to 62.5%. Nothing is held back. The full benefit lands directly in your pension check, month after month.

BRS starts you lower — 40% of that same High-3 average at the 20-year mark, with the identical 2.5% annual escalation beyond that. The catch is enormous, though. You’re also supposed to be building a Thrift Savings Plan account through government matching contributions the entire time. The Pentagon’s logic: the smaller pension gets offset by retirement savings you actually own and can take with you. We’ll get into that match shortly.

Probably should have opened with this section, honestly — it’s the foundational decision that shapes literally everything else. Service members who joined before 2018 can opt into BRS voluntarily, but most don’t bother.

Under the old High-3 system, the military carried virtually all retirement risk. Live to 95, the government pays you from age 42 forward — their problem entirely. Under BRS, you’re building a portable account that belongs to you regardless of how long you serve. Leave at year 15 with no pension? Your TSP balance still comes with you. It’s genuinely different risk allocation, not just a straight benefit cut dressed up in nicer language.

How to Calculate Your Estimated Retirement Pay

The math itself isn’t complicated. You need three things: your highest 36-month average base pay, your years of service, and whether you’re High-3 or BRS. That’s it.

For High-3, the formula looks like this:

Highest-36-months average base pay × 2.5% × years of service = annual pension

For BRS, swap that 2.5% for 2.0%:

Highest-36-months average base pay × 2.0% × years of service = annual pension

Let me walk through a real example — an E-7 with exactly 20 years of service. Last three years of base pay: $58,200 in year 38, $59,400 in year 39, $61,100 in year 40. Add those up and divide by three. Your High-3 average is $59,567.

Under High-3: $59,567 × 50% = $29,783 annual pension. Divide by 12 and you’re looking at $2,482 monthly before taxes.

Under BRS: $59,567 × 40% = $23,827 annually. That’s $1,986 per month. The gap is nearly $500 every single month — $6,000 per year. Stretch that across 40 years of retirement and you’re talking about a quarter-million dollars in reduced pension payments. Worth doing the arithmetic on that before you sign anything.

Now run the same calculation for an O-5 — Commander or Lieutenant Colonel, depending on your branch. Using 2026 pay scales, a 20-year O-5 has a High-3 average of roughly $118,300. Under High-3: $118,300 × 50% = $59,150 annually, or $4,929 monthly. Under BRS: $118,300 × 40% = $47,320 annually, or $3,943 monthly. The monthly gap widens to nearly $1,000. Same percentage difference, much bigger dollar impact — because rank matters when you’re multiplying.

At 25 years of service, the E-7 High-3 pension hits $37,229 annually ($3,102 monthly), while the BRS equivalent lands at $29,783 annually ($2,482 monthly). The formula stays the same regardless of whether you hit the 20-year mark exactly or push to 25.

One thing the military is strict about: base pay only. Basic Allowance for Housing — BAH — doesn’t count. Neither does Basic Allowance for Subsistence, BAS, or any special pays. Only the base salary number factors into your High-3 average. Don’t make my mistake of assuming otherwise until someone corrects you at a finance brief in year sixteen.

The TSP Match Under BRS

Frustrated by that lower pension number, I initially wrote off BRS as a bad deal across the board. Then I actually modeled what the government match compounds to over time — and the math shifted on me.

Here’s how the BRS match works. After your first two years of service, the Department of Defense automatically deposits 1% of your base pay into your TSP account, regardless of whether you contribute a single dollar yourself. Starting at year three, the government matches your contributions dollar-for-dollar up to 5% of base pay. Contribute 5%, they add 5%. Contribute 3%, they match 3%. The ceiling is 5% on their end.

Back to that E-7 with $59,567 annual base pay. The automatic 1% contribution alone is $596 per year — free money, no action required. If that service member then contributes 5% of base pay ($2,978), the government layers in another $2,978. Total annual TSP deposits: $6,552. That’s $6,552 going into a retirement account every year on top of whatever pension they’re accruing.

Over 20 years, assuming a conservative 6% annual return in something like the L2045 lifecycle fund, that $6,552 annual contribution compounds to approximately $229,000. A more aggressive C-Fund or S-Fund allocation might push that to $265,000. Someone who contributes nothing beyond the automatic 1%? They’re walking away with roughly $95,000. Same service, very different outcomes — entirely based on contribution habits.

That’s what makes BRS endearing to financial planners, honestly. The BRS service member accepts a smaller monthly pension but walks away with a portable, fully-owned TSP balance. The High-3 retiree gets the full pension and nothing portable if they exit exactly at 20 years.

The Pentagon’s stated argument: BRS provides more flexibility. Leave at year 15 under High-3 — no pension, nothing. Leave at year 15 under BRS — no pension yet, but your TSP travels with you. The trade works cleanly if you stay until 20, because then you collect both the pension and the accumulated TSP balance simultaneously.

The critical issue is contribution discipline. I’m apparently the type who sets automatic contributions and forgets about them, and that approach works for me while manual budgeting strategies never stuck. If you’re a BRS service member earning $59,567 and you contribute 0% beyond the automatic 1%, you’re forfeiting $6,000-plus in annual employer matching. That’s a deliberate choice to accept the lower benefit with nothing supplementing it. Don’t make my mistake of not modeling this out early in your service.

COLA and How Your Pension Grows After Retirement

Your pension doesn’t stay frozen at $2,482 monthly for the next five decades. It adjusts. But the rate of that adjustment depends entirely on which system you’re under — and the difference adds up faster than people expect.

High-3 pensions receive a full Cost-of-Living Adjustment every January, tied to the Consumer Price Index for All Urban Consumers, CPI-U. In 2025, that adjustment was 2.4%. In 2024, it was 3.2%. In 2022, it spiked to 8.7% when inflation ran hot. Your monthly check moves in lockstep with that index, full stop.

BRS pensions receive the same CPI-U adjustment — minus one full percentage point — until you hit age 62. So if CPI-U prints 3%, your BRS pension grows by 2%. If CPI-U comes in at 2.4%, your check grows by 1.4%. Then, on your 62nd birthday, you receive a one-time catch-up adjustment that theoretically restores parity with what you’d have received under full COLA. Theoretically.

In practice, this creates a real wedge. That E-7 example with a $23,827 first-year BRS pension — applying the CPI-U minus 1% adjustment across 20 years from age 42 to 62 — ends up at roughly $31,400 instead of the $35,200 the full COLA would have delivered. The catch-up bump closes some of that gap at 62. Not all of it. The lifetime impact runs into tens of thousands of dollars in reduced benefits, compounding quietly the entire time.

The Pentagon’s rationale: your TSP portfolio continues growing during those same years, theoretically offsetting the reduced pension COLA. It’s an intentional trade — lower spending power in early retirement, more reliance on your own portfolio performance. For someone who maintained 5% contributions and a diversified allocation across their service years, this works. For someone who ignored TSP entirely, it produces a measurable reduction in post-62 living standards.

The honest assessment: the COLA difference feels manageable in the first decade of retirement. By year 20 or 25 outside the service, it becomes genuinely significant — not devastating, but significant. Run the numbers for your specific situation rather than assuming it washes out.

What 20-Year Retirement Actually Pays in 2026

Spreadsheet percentages don’t pay grocery bills. So let’s ground this in actual monthly amounts, with taxes factored in.

An E-7 with 20 years under High-3 receives $29,783 in annual gross pension — $2,482 monthly before anything gets withheld. Military pensions are federally taxable income. Filing single with no other income, that E-7 owes roughly $195 per month in federal taxes. Net take-home: approximately $2,287. Individual situations with dependents, credits, or additional income will vary from that figure.

The same E-7 under BRS receives $23,827 annually — $1,986 monthly gross. Federal withholding drops to about $145 per month. Net take-home: $1,841. The real-world difference is $446 per month, or $5,352 per year. For a family running a household budget, that gap is significant.

Now layer in the TSP. If that BRS service member contributed 5% and captured the full 5% government match across 20 years, they’re retiring with approximately $229,000 in a portable account. Convert that to an immediate annuity at age 42 and it adds roughly $950 monthly to the income stream. Leave it invested and take systematic withdrawals and you gain flexibility — but also carry market timing risk. Neither approach is automatically right.

An O-4 — Major or Lieutenant Commander — with 20 years under High-3 pulls $59,150 annually, or $4,929 monthly gross. Federal withholding runs about $370 monthly. Net take-home: $4,559.

Same O-4 under BRS receives $47,320 annually, or $3,944 monthly gross. Federal withholding drops to roughly $280 monthly. Net take-home: $3,664. The monthly gap is $895 — nearly $11,000 annually. That’s a car payment, a family vacation, a meaningful chunk of a kid’s college fund.

With consistent 5% TSP contributions and full matching across 20 years, that O-4’s TSP balance reaches approximately $458,000. Annuitized, that’s roughly $1,900 in additional monthly income. Combined BRS pension plus annuitized TSP: $5,564 monthly — which actually edges past the High-3 pension at initial payout. The math works, but only if the contributions actually happened. Many O-4s contribute 2% or 3% and capture only partial matching. Some contribute nothing beyond the automatic 1%, leaving tens of thousands of dollars sitting unclaimed.

One practical detail worth knowing: military retirement pay is subject to federal income tax but exempt from most state income taxes, even in high-tax states. An O-4 collecting $4,929 monthly in California carries a real net advantage over equivalent private-sector income at that level. That state exemption isn’t nothing — it’s meaningful, especially in states with 9% or 10% income tax rates.

By late 2026, these specific numbers will have shifted slightly due to regular military pay raises — typically 2.5% to 3.5% annually. The ratios and trade-offs, though, stay consistent regardless of the pay cycle.

So, without further ado, the honest bottom line: High-3 delivers more immediate monthly income with less effort required from you. BRS makes you your own retirement manager — but offers portability and the potential for higher total retirement wealth if you stay disciplined with TSP contributions across all 20 years. Neither system is wrong. They distribute risk differently, and which one serves you better depends almost entirely on your contribution habits and how long you actually stay in uniform.