Retirement Income Gap Calculator Methodology

Quick estimate inputs and units

The required input is a desired monthly retirement income amount. The other monthly inputs are estimated Social Security, pension, savings or investment income, and other recurring income. All amount fields accept nonnegative values up to $1 trillion, though values at that limit are valid technically and may not be practical estimates. Optional blank income fields are treated as zero; a blank goal is incomplete, while $0 is a valid entered goal. The calculator supports a combined household estimate if all inputs refer to the same household.

Enter monthly amounts, in U.S. dollars and today’s dollars, using one consistent before-tax or after-tax basis. The display rounds amounts to whole dollars; the calculations retain input precision until display. Invalid, negative, nonnumeric, or out-of-range values do not produce a result.

Quick estimate formulas

A goal above income produces a gap and zero surplus. Income above the goal produces a zero gap and a surplus. Equal amounts produce zero for both. The annual figure repeats the current monthly gap for 12 months; it is not a projected retirement-long total or required savings balance.

Optional savings projection

The detailed estimate accepts current age, planned retirement age, current retirement savings, a monthly contribution, an annual real-return assumption, and an annual withdrawal-rate assumption. Ages are whole years from 0 to 120. If planned age is below current age, the model treats the user as already retired and sets future months to zero. Savings and monthly contribution are nonnegative amounts up to $1 trillion. Annual real return can range from −20% to 20%; annual withdrawal rate can range from 0% to 100%.

The contribution formula assumes deposits at each month’s end, constant contributions in real purchasing power, and a constant monthly real rate derived by dividing the entered annual rate by 12. The default annual real return is 3%; the default withdrawal rate is 4%. Both can be edited. These assumptions are not predictions, safe withdrawal guidance, or guarantees.

What the estimate includes and leaves out

The quick calculation includes only the goal and income figures entered. The optional projection estimates a future savings balance from its inputs and an implied monthly amount under the selected withdrawal rate. It does not model taxes, account fees, different asset returns, market volatility, sequence of returns, benefit cost-of-living changes, pension survivor options, retirement dates for two people, household expense changes, medical costs, insurance coverage, debts, longevity, inflation separately, or how long a balance will last after withdrawals.

Because it does not model depletion, the monthly savings income is not a sustainable-income guarantee. A positive gap is not the amount of money to save, and a zero gap or surplus does not establish retirement readiness. Compare results with detailed household records and appropriate professional guidance. Learn more in the guide to interpreting a gap and the worked examples.

Preparing an estimate

Before entering values, prepare a monthly household budget, your benefit estimate, pension statements, and any other recurring income figures. Do not enter account numbers, Social Security numbers, or upload documents; the calculator does not need them. Choose one household scope, one tax basis, and today’s dollars for all entries.

To see personalized Social Security estimates, use the SSA benefit estimate service. For general retirement-income education, see Investor.gov’s retirement income information. For general background on the tax treatment of plan distributions, see the IRS overview of tax on normal distributions; personal tax questions require current, situation-specific guidance. These external sources are provided for reference; the calculator does not import data from them.