How Much Money Do I Need to Retire? A Cash-Flow Worksheet

Use one consistent tax convention

This worksheet uses gross nonportfolio income and spending excluding income tax, with one separate income-tax allowance. Healthcare belongs in spending exactly once. The tax allowance is illustrative: actual withdrawals can change taxes, so the full projection must iterate the cash need.

Test the assumptions before treating a multiple as a target

Divide a representative annual portfolio gap by an illustrative starting rate. The table omits timing, market returns, inflation, longevity and future taxes; it is arithmetic, not a safe-withdrawal recommendation. The $60,000 bridge-year gap in the worksheet is temporary and should not automatically become a permanent annual withdrawal.

Keep the temporary bridge separate

For this household, three years at $60,000 and two at $54,000 total $288,000 before growth or discounting. Compare that with assets available at those dates using the bridge-number worksheet. Then model the longer $20,000 annual gap and shocks through the chosen horizon.

If using after-tax income instead, compare it with spending that excludes the taxes already withheld or allocated. Do not subtract after-tax benefits and then add their tax a second time. The spending worksheet keeps the categories visible.

Why one retirement number can mislead

Rules such as saving a multiple of salary are convenient because salary is easy to find. Retirement, however, is funded by spending rather than salary. A high earner who saves aggressively and expects modest retirement spending may need a smaller share of final pay than someone whose paycheck mostly supports current expenses.

Timing also changes the answer. Retiring several years before Social Security and Medicare can create a temporary funding peak. Claiming benefits later may increase dependable lifetime income, but the portfolio must carry more of the early years. A total balance hides that timing; a cash-flow timeline reveals it.

Planning takeaway

Replace the question 'What is my number?' with 'What range supports my plan, and what assumptions drive it?'

Estimate the portfolio's annual job

Begin with household spending in today's dollars, including healthcare, repairs, vehicles, and family support. Exclude income tax from that spending subtotal, add one separate tax estimate, and subtract gross nonportfolio income in each year it actually begins.

The remainder is the withdrawal gap. If spending excluding income tax is $90,000, the separate tax allowance is $8,000, and gross dependable income is $45,000, investments must fund $53,000 for that phase. Do not add a second tax allowance. The gap may be much larger in the first five years and smaller later, so calculate it year by year when possible.

• Use today's dollarsThis makes the result intuitive. The model can then apply inflation consistently.
• Separate essentialsKnowing what can be trimmed gives the plan a response when markets are weak.
• Model both livesFor couples, test the longer survivor horizon and changes to income after the first death.

Convert the gap into a planning range

Dividing the first-year withdrawal gap by a starting withdrawal rate can provide a rough portfolio estimate. For example, a $40,000 gap divided by 4% equals $1 million. This is a shorthand, not a complete plan. It assumes the first-year gap resembles later years and does not fully capture taxes, changing income, large expenses, or poor return timing.

Create at least three versions: a base case, a lean case that uses realistic spending flexibility, and a higher-cost case with more inflation or a major expense. Then run each through the same modeling assumptions. The overlap among workable versions is more informative than a falsely precise target.

Planning takeaway

A range shows which parts of the plan are sturdy and which depend on favorable assumptions.

Improve the plan without only saving more

Saving more is one lever, but it is not the only one. Delaying retirement can add contributions, shorten the withdrawal period, and preserve employer health coverage. Adjusting Social Security timing changes the shape of dependable income. Paying off or downsizing a home changes recurring spending. Tax-diverse accounts can create more control over taxable income.

Compare one change at a time so you know what helped. A useful model should show the before-and-after effect on cash flow, critical downside paths, and modeled success. Avoid chasing 100%; uncertainty cannot be eliminated. The goal is to build enough margin and flexibility that a disappointing path still has a response.