Pension vs 401(k) Calculator: How to Use It

What this calculator does

The Pension vs 401(k) Calculator converts both retirement vehicles into the same unit of measurement: monthly income. It calculates your pension benefit from your salary, years of service, and multiplier, then projects your 401(k) balance at retirement and converts it to equivalent monthly income at your chosen withdrawal rate. The result is a direct side-by-side comparison.

The calculator also shows the equivalent 401(k) balance you would need to match your pension income, the 20-year and 30-year cumulative payout from each, and how inflation erodes purchasing power over time. A separate section shows the break-even year of service: the point at which staying longer in a pension job becomes clearly superior to leaving for a 401(k) employer.

What each input means

Final average salary

Most pension formulas use final average salary (FAS), typically the average of your last 3 or 5 years of earnings. Some plans use career average salary, which is lower and produces a smaller benefit. Enter the salary your plan uses for the calculation. If your plan uses a 3-year average and your last three years were $85,000, $88,000, and $91,000, enter $88,000.

Years of service

The number of years you'll have in the pension plan at retirement. This is the multiplier in the formula. Most pension plans use a formula like: final average salary times years of service times the benefit multiplier. Going from 20 to 25 years doesn't just add 5 years of credit; at a 1.5% multiplier on a $90,000 salary, that's an additional $6,750 per year in pension income, for life.

Benefit multiplier

The percentage of salary credited per year of service. Common figures: 1.0% to 1.5% for private pensions, 1.5% to 2.5% for public plans. FERS federal employees use 1.0% (or 1.1% at 62 with 20 years). Some teacher plans use 2.0% or higher after a certain number of years. Find this in your plan's summary plan description or benefits handbook.

401(k) contribution rate and employer match

Your annual contribution as a percentage of salary plus any employer match. The match is free money that makes the 401(k) more competitive. A 100% match up to 5% of salary effectively doubles those contributions. Enter both to get the correct projected balance. Growth rate defaults to 7%, which is roughly the historical real return of a diversified equity portfolio before fees.

Withdrawal rate

The percentage of your 401(k) balance you'd withdraw annually in retirement. This converts the balance to monthly income. 4% is the standard based on William Bengen's 1994 research (30-year historical survival). For a 35+ year retirement, 3.5% or 3% is more conservative. The calculator defaults to 4%, but changing this to 3% increases the equivalent 401(k) balance you need by 33%.

Understanding the outputs

The "equivalent 401(k) balance" figure surprises most people. It's the account balance you'd need at retirement to generate the same monthly income as your pension, at your chosen withdrawal rate. A $2,500/month pension is worth $750,000 in 401(k) terms at 4%, or $1,000,000 at 3%. If your projected 401(k) lands at $450,000, the pension provides more monthly income by a substantial margin.

The 20-year and 30-year cumulative totals show the pension's total nominal payout vs. what the 401(k) generates over the same periods. The 401(k) total includes the residual balance still in the account. A 401(k) that isn't fully drawn down by year 30 has remaining value that the pension doesn't leave behind.

The inflation-adjusted column shows real purchasing power. A fixed pension that pays $2,500 now pays the equivalent of about $1,850 at age 85 in today's dollars at 2% annual inflation over 20 years. A 401(k) portfolio invested in equities at least attempts to keep pace.

Break-even analysis: how long do you need to stay?

Pension benefits accrue nonlinearly. Early years produce small benefits. The back half of a career produces disproportionately large ones, because years of service multiply against a higher final salary. At a 1.5% multiplier, 10 years of service produces 15% of salary. 25 years produces 37.5%. The benefit nearly doubles for 2.5 times the service.

The break-even analysis in the calculator shows the years of service at which the pension's projected total lifetime payout exceeds what the 401(k) path would produce. For most plans, that crossover sits somewhere between 12 and 18 years. Below that threshold, the portable 401(k) with a decent employer match often wins. Above it, the pension becomes very hard to replicate.

PBGC insurance and the employer risk question

The Pension Benefit Guaranty Corporation insures most private-sector defined benefit pensions. The 2026 maximum guarantee is roughly $7,285 per month ($87,420/year) for a 65-year-old on a single-life annuity. If your pension is below that ceiling, employer insolvency is not a realistic risk. If your expected benefit exceeds the cap, the excess is not guaranteed and depends on the plan's funding status.

Government pensions, including FERS, CSRS, military retirement, and state teacher plans, are not insured by the PBGC. They're backed by government taxing authority instead, which is a different kind of assurance. A 401(k) has no employer credit risk at all: it's held in a trust separate from the employer, protected by ERISA.