Can Your Tax Return Tell You What You Spend in Retirement?
You’re updating your retirement plan and want one reliable spending number. Last year’s tax return seems like a sensible place to start. Subtract Social Security and pension income from adjusted gross income, divide the remainder by twelve, and you have a monthly estimate.
That calculation can feel convincing without measuring what you spent. Before it persuades you to cut back, withdraw more, or change investments, follow the money beyond the return. The useful question is which amount represents the life your plan needs to support.
What does your tax return actually measure?
Adjusted gross income, or AGI, is gross income minus certain adjustments. It is calculated before the standard or itemized deduction. It is a tax measure, not a household spending total.[1]
Some taxable income may never reach your checking account. Interest or dividends might stay invested. The cash you use and the income reported on your return may also differ. When you sell an investment in a taxable account, the gain or loss depends on its adjusted cost basis; the full sale proceeds are not automatically taxable income.[2]
Subtracting benefits from AGI therefore can’t reliably tell you how much of your spending came from your portfolio. You may be subtracting cash received from a number that includes only its taxable portion. You may also overlook money spent from existing savings. The shortcut combines amounts before you know whether they describe the same dollars.
Why can one withdrawal produce several different totals?
A traditional IRA distribution may be fully or partly taxable, depending on the account’s basis and applicable rules. Qualified Roth IRA distributions generally aren’t included in gross income. Tax withheld from a traditional IRA distribution reduces the deposit reaching you, rather than proving how much you spent.[3]
Consider an ordinary $40,000 distribution from an entirely pretax traditional IRA. Assume $8,000 is withheld for taxes, $32,000 reaches your checking account, and you use $27,000 for household bills and purchases. The remaining $5,000 stays in checking. Those numbers answer different questions.
One withdrawal. Three different numbers.
$40,000
Taxable IRA distribution
Includes $8,000 sent for tax withholding.
$32,000
Deposit into checking
After withholding; $5,000 remains unspent.
$27,000
Household bills and purchases
The portion used for these expenses.
Understand the differences before setting next year’s spending.
Illustration only. Assumes no fees or additional tax on early distributions. Withholding is not a recommended rate or the final tax bill.
Dovetail Principle: Financial Decisions Need to Fit Together
Each number has a legitimate purpose. Your tax return helps explain your taxes, while account records show where your money moved and household records show how you used it. Connecting them lets you change a planning assumption for a reason you can explain, rather than because one total looks authoritative.
How can you find the spending behind the tax figure?
Start with the same twelve-month period across bank, credit-card, and investment records. FINRA recommends tracking monthly income and expenses as part of a spending plan.[4] Use the return to help explain the funding, rather than treating it as the spending record.
Trace material withdrawals to their destinations. Separate taxes withheld before deposit from money that reached checking. Identify transfers between your own accounts and cash still saved at year-end. If you count credit-card purchases, don’t count the later payment of those same purchases again.
Keep two useful totals: household bills and purchases, and the broader funding need that also provides for taxes and other commitments. Label what each includes. A lower everyday-spending figure does not make the tax cost disappear, and a larger gross withdrawal does not establish a more expensive lifestyle.
Which parts of last year belong in next year’s plan?
Even an accurate historical total needs interpretation. Society of Actuaries research found that retirees often understood recurring expenses but did not plan for extraordinary costs such as roof replacement or large medical expenses.[5] A quiet year can understate the future need just as a major purchase can overstate an ordinary year.
Look at each significant expense on its own. Was it completed, likely to recur, or something you want to do differently? In EBRI’s 2024 Spending in Retirement Survey, 36% of retirees reported unexpected spending needs since retirement.[6] Allow for irregular costs without pretending the same surprise will happen every year.
What should you change once the differences are clear?
Ask your advisor to test your estimate of future spending, supported by your records, alongside income, taxes, and portfolio withdrawals. Your tax preparer should resolve uncertain tax treatment. If an unexplained difference is large enough to affect your decision, leave the assumption unresolved rather than choosing the most reassuring total.
The result may support keeping your routine, changing a withdrawal, or reconsidering a spending choice. It may simply show that last year’s tax figure was answering a different question. Use your return to understand what happened, then base the next decision on what your household actually needs and wants to fund.
Once you have a supported spending estimate, What Should You Measure Before Setting a Monthly Retirement Paycheck? connects that estimate with the monthly transfer. The companion articles explain the checking-account routine and the tax effects of funding it.
