The question
The core question is: if you leave federal service today, how much extra private-sector compensation must you earn each year so that by planned retirement you can replace the federal benefits you gave up? The answer is not simply the difference between your federal salary and a job offer. It is a benefit replacement problem.
Lost pension
The largest component is often lost FERS pension. The model compares the pension you would earn by staying to the deferred pension you keep if you leave after vesting. The gap is valued as a stream of future payments and discounted into today's dollars.
If you leave before vesting, deferred pension can be zero. If you leave after vesting, the deferred annuity is based on salary and years of service at departure, not at your future retirement date.
Lost FEHB subsidy
Retiree FEHB can be worth $8,000–$15,000 per year because the government continues paying much of the premium for eligible retirees. If leaving federal service prevents immediate retirement eligibility later, that subsidy may be permanently lost.
Lost TSP match
Future agency TSP match is another benefit stream. FERS employees can receive up to 5% of salary in agency contributions. Leaving means future match stops. A private 401(k) match can offset some of that, but only if it is comparable and vested.
Required premium
After valuing lost pension, FEHB, and match, the model converts required replacement wealth into annual extra salary. Taxes matter because extra salary is taxable before it can be saved or invested.
The final result is the annual private-sector premium needed above your federal compensation path. Use it as a negotiation floor, not a guarantee.
Why timing changes the answer
The break-even premium usually rises as you get closer to retirement because there are fewer working years left to replace lost benefits. If a 35-year-old leaves federal service, a private-sector premium can compound for decades. If a 55-year-old leaves, there may be only a few years left before the original retirement target. The same lost pension value must be replaced over a shorter runway, so the required annual premium can be much larger.
Vesting also changes the answer. Before 5 years of service, leaving can mean losing the entire FERS pension. After vesting, a deferred annuity may remain, but it is based on salary and service at departure. The break-even model subtracts that retained deferred value from the stay value rather than assuming the entire pension disappears.
Tax drag
Private salary is not the same as investable savings. If you need to save $20,000 per year after tax to replace lost benefits, the employer must pay more than $20,000 in gross salary. Federal income tax, state income tax, payroll tax, and benefit costs can reduce the amount available to invest. This is why the model grosses up required savings by an assumed tax rate.
What can offset the loss
A private-sector job may include higher salary, equity, bonus potential, a better 401(k) match, subsidized healthcare, or more career upside. Those can offset federal benefits if they are durable and vested. The model is not saying private work is bad. It is forcing the offer to clear the full economic value of what federal service provides.
Equity compensation deserves special caution. Stock options or RSUs can be valuable, but they carry market and employer risk. A guaranteed pension and FEHB subsidy are different assets from performance-based compensation. A good comparison discounts risky compensation more heavily than guaranteed government benefits.
How to use the result
Use the break-even premium as a decision anchor. If a private offer is below the break-even number, you may still accept it for lifestyle, location, mission, or growth reasons, but you should know you are likely giving up financial value. If the offer is above break-even, the move may be financially viable, especially if it also improves quality of life.