Pension Calculator

A defined-benefit pension pays a guaranteed income for life, worked out from a formula rather than from an investment pot you have to manage. Almost every plan of this kind uses the same three ingredients.

The formula: Annual Pension = Final Average Salary × Years of Service × Pension Factor

The pension factor, also called the accrual rate or the multiplier, is the slice of salary you earn for every year worked. Divide the annual figure by 12 for the monthly payment.

Worked example: Final average salary $65,000, 23 years of service, a 2% factor.

Annual pension = $65,000 × 23 × 0.02 = $29,900 Monthly = $29,900 ÷ 12 = $2,491.67 Replacement rate = 23 × 2% = 46% of final salary

That last line is the shortcut worth carrying around: years of service × factor is your replacement rate. You do not need to know the salary to work it out.

Typical factors:

Final average salary is not your last paycheck. Most plans average the highest three or five consecutive years, so a promotion in the final year moves the number far less than people expect. Some plans count overtime and cashed-out leave, others deliberately exclude both, and that one definition can swing the result by more than any argument about the factor. It is in the plan document, and it is worth reading before you count on a figure.

Single life versus joint and survivor What this calculator produces is the single-life amount, which is the largest number the plan will ever quote you. Electing a survivor benefit trades part of it away, because the plan is now paying across two lifetimes instead of one. The reduction depends on the survivor percentage you pick and the age gap between you, it is an actuarial calculation rather than a penalty, and it is not something to estimate. Ask the plan for the exact options in writing.

What the formula leaves out Whether the payment rises with inflation is the single biggest unknown. A cost-of-living adjustment is common in public plans and rare in corporate ones, and across a 25-year retirement that difference dwarfs a tenth of a percent on the factor. Vesting matters too: leave before you vest and those years count for nothing at all. Retiring early usually carries a reduction of its own on top.