A pension vs. 401(k) calculator compares lifetime pension income with a 401(k) balance built from worker and employer contributions.
A pension, usually a defined-benefit plan, promises a set monthly payment at retirement, while a 401(k), a defined-contribution plan, holds individual contributions and investment growth. Use one calculator for each plan type, then compare monthly spending power side by side. Correct salary, tenure, contribution, fee, inflation, and tax entries decide whether the result is useful.
Table of Contents
- What does each calculator ask you to enter?
- How is the pension amount figured?
- Which assumptions move both results?
- How should you read risk and monthly income?
What does each calculator ask you to enter?
A 401(k) calculator starts with current salary, contribution rate, employer match rate, and current balance. These entries set annual deposits and the base for growth. The calculator must also respect federal contribution caps. According to the Internal Revenue Service, elective deferrals are capped at $24,500 for 2026, up from $23,500 in 2025, as explained in the IRS 2026 limit announcement.
A pension calculator asks for different facts. The U.S. Department of Labor defines defined-benefit plans as promising a specific retirement benefit, while defined-contribution plans specify only amounts paid into individual accounts, as described on the Labor Department plan-types page. So expect pension fields for benefit formula, salary history, service years, retirement age, and survivor option.
- Gather pay stubs for salary and contribution rate.
- Gather plan statements for balance, match formula, and pension multiplier.
- Enter exact birth date and planned retirement date.
- Save each run with its return, fee, and inflation settings.
How is the pension amount figured?
Most pensions multiply final or average salary by years of service and a benefit multiplier. A common pattern is 1.5 percent times years times final pay, so longer tenure and higher late-career pay raise the check. That formula makes service breaks and salary drops matter.
Ten extra years can lift the benefit more than a late raise, while part-time years may lower average pay. Check whether your plan uses final pay, three-year average, or career average. Then match overtime, bonuses, and unused leave rules to the plan definition before you trust the monthly figure.
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Which assumptions move both results?
Longevity sets how long payments and withdrawals must last. Social Security Administration data used in the 2025 Trustees Report shows remaining life expectancy at age 65 of about 17.5 years for men and 20.1 years for women. Investment return, fees, inflation, and taxes move the 401(k) side more.
Even a one-point fee gap compounds hard: Department of Labor guidance shows a 1-point higher annual fee cuts a 35-year account by 28 percent, turning $227,000 at 0.5 percent fees into $163,000 at 1.5 percent fees, per the Labor Department fee guide. Inflation and taxes shape spending power for both plans. The Federal Reserve targets about 2 percent long-run inflation, while traditional 401(k) withdrawals face ordinary income tax and qualified Roth withdrawals are tax-free, so a large nominal balance still buys less.
How should you read risk and monthly income?
A pension result is a promised payment, not a cash balance, and it carries plan solvency risk. Federal insurance limits that risk: according to the Congressional Research Service PBGC primer, the Pension Benefit Guaranty Corporation guarantees up to $93,477 per year for a 65-year-old straight-life annuity in plans terminating in 2026, or about $7,789 per month, as reported in the CRS PBGC primer. A 401(k) result is a projected balance plus an assumed withdrawal path.
Read it as a range tied to fees, returns, and lifespan, not a guaranteed paycheck. Compare after-tax monthly income in current dollars, then test lower returns, higher fees, longer life, and reduced pension coverage. Keep the run that still covers essential costs.
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