Planning

Updated April 18, 2026

Retirement gap analysis: what do I need from the sale to stop working

Before the seller negotiates price or structure, the prior question is: how much do I actually need from this sale, combined with Social Security and other savings, to live on. This page walks through the math at a working level. It is not financial advice. It is the framework the seller should use in the first conversation with a CPA or a fiduciary financial planner.

Why this has to come first

A seller who starts the sale process without a target net-proceeds number can end up agreeing to a price or a structure that looks acceptable in isolation but leaves a retirement shortfall that only becomes visible years later. The goal of this page is to frame the math early, so every offer is evaluated against a specific number.

The math has 3 inputs. Annual living cost in retirement. Other income (Social Security, any pension, any retirement savings, spouse's income). The gap between cost and income, which is what the sale proceeds (plus existing savings) have to cover for the rest of the seller's life.

Step 1: estimate annual living cost in retirement

Most retirement-planning models use some version of the 80% rule: retirement spending is often 70% to 85% of pre-retirement working-year spending, because some costs (commuting, work wardrobe, retirement savings contributions) go away. Healthcare costs typically go up, especially before Medicare eligibility at age 65.

For a business owner with a current working-year household spending of $100,000, a common starting estimate for retirement is $75,000 to $90,000 per year, adjusted for the specific profile. This is a rough anchor, not a rule.

Work through the actual budget: housing (mortgage, taxes, insurance, maintenance), healthcare (pre-Medicare premiums can exceed $1,000 per month for a single person, more for couples; Medicare plus supplement runs less but is not free), food, transportation, travel, family support, charitable giving, property taxes on any vacation home or investment property.

Step 2: add up other income sources

Social Security. The Social Security Administration publishes estimated benefits at ssa.gov/myaccount. Benefits depend on work history and the age at which benefits start. Starting at age 62 reduces the benefit permanently; delaying past full retirement age increases it. A seller near retirement age should pull the current estimate before running the math.

Retirement accounts. Existing 401(k), IRA, SEP-IRA, or SIMPLE-IRA balances. The standard planning assumption is that a diversified portfolio can support annual withdrawals around 3.5% to 4% of the starting balance, adjusted for inflation, for a 30-year retirement. A $500,000 balance supports roughly $17,500 to $20,000 in year-1 withdrawals under that assumption. This is the 'safe withdrawal rate' framework; it is a rule of thumb, not a guarantee.

Pensions. If the seller has any defined-benefit pension from a prior employer, union, or military service, pull the current estimate of the monthly benefit.

Spouse income. A spouse who will continue working, or whose pension starts at a different date, affects the gap meaningfully.

Social Security taxation. Up to 85% of Social Security benefits may be taxable depending on total income. IRS Publication 915 covers the calculation.

Step 3: solve for the gap

Annual living cost minus annual other income is the annual gap the sale proceeds have to fill. Multiply the gap by the expected retirement length (life expectancy minus planned retirement age; a 60-year-old has a life expectancy of roughly 22 to 24 more years per Social Security Administration actuarial tables).

Inflation matters. A $30,000 annual gap today is a $45,000 annual gap in 15 years at 3% inflation. A financial planner uses a simulation (Monte Carlo or similar) that includes inflation and market-return variability; the simple math below is a first-pass anchor, not a plan.

Simple anchor calculation. If the annual gap is $40,000, the retirement horizon is 25 years, the portfolio is invested with roughly a 4% real (after-inflation) return, and the 4% safe-withdrawal rate applies, the seller needs approximately $1,000,000 from the sale plus existing savings to fund the gap for 25 years. This is a rough starting number, not a plan.

Step 4: model the sale against the gap

Headline sale price is not the same as net proceeds. From gross price, subtract: broker fees (commonly 10% on deals under $1M), legal fees, CPA fees, any debt repayment at close, federal capital gains tax (currently 15% to 20% long-term, plus 3.8% net investment income tax for higher earners), state income tax (varies by state; some states tax capital gains as ordinary income), and depreciation recapture on equipment (taxed at ordinary income rates up to a cap).

A $1.8M headline sale on a business with $300K of depreciation recapture, 10% broker, $40K legal and CPA, and roughly 25% combined federal and state tax on the remaining gain can net closer to $1.15M to $1.25M at close. Every deal is different. The deal CPA should run the model with specific numbers before the LOI is signed.

If the structure includes seller financing or an earnout, the after-tax net-at-close drops further, with the contingent payments arriving over years. The seller should ask: can I retire safely on the cash-at-close alone, treating the seller note and earnout as upside. For a seller without a large existing nest egg, the answer to that question often determines whether seller financing is an appropriate risk.

When the gap does not close

Sometimes the honest answer to the analysis is that the expected sale proceeds plus other income do not close the gap. Several paths forward. Wait longer before selling (more years of earnings, more years of retirement-account contributions, potentially higher valuation as the business grows). Adjust the retirement-spending target. Take a structure with less seller risk even at a lower headline price. Move to a lower-cost metro. Keep part-time income from consulting or the transition agreement.

A fiduciary financial planner (fee-only, CFP designation) runs this analysis formally and can model multiple scenarios. The seller's CPA may also offer this service or refer to one. The planner is paid for advice, not for selling products; that distinction matters.

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