Retirement Income in Florida: How Much of Social Security and a Pension Is Taxable Federally?

Part of your Social Security may be taxable on your federal return, and a pension is usually taxable in whole or in part, depending on whether you paid tax on the money you put in. Whether any Social Security is taxable depends on your "combined income," not on your benefits alone. This post covers federal rules only. Florida does not have a personal income tax, and nothing here addresses any other state.

How much of my Social Security is taxable?

Start with your Form SSA-1099 or RRB-1099. Box 5 shows your net benefits after Medicare premiums and other deductions, and that is the figure to use (Publication 915, Social Security and Equivalent Railroad Retirement Benefits). Next, take half of your Social Security benefits and add your other income, including tax-exempt interest. That total is your combined income. Then compare it with the base amount for your filing status:

• Single, head of household, or qualifying surviving spouse: base amount $25,000. Up to 50% of benefits can be taxable above that, and up to 85% above $34,000.
• Married filing jointly: base amount $32,000. Up to 85% can be taxable above $44,000.
• Married filing separately and lived with your spouse at any time in the year: base amount $0, so up to 85% can be taxable.

If your combined income is at or below the base amount, none of your benefits are taxable. Publication 915 has the worksheets for the exact math.

How is my pension taxable?

Your pension payer reports distributions on Form 1099-R, and the total goes on line 5a of Form 1040. If the payments are fully taxable, which is the case when you did not contribute after-tax money to the plan, you enter the Form 1099-R box 1 total on line 5b and leave line 5a blank (Form 1040 instructions). If you did contribute after-tax money, part of each payment may be tax-free. In that case, follow the general rule or the simplified method in Publication 939, or use the taxable amount if your Form 1099-R shows it.

Worked example

Illustration only, with made-up round numbers: Maria is 67, single, and files for 2026. Her Social Security net benefits in Box 5 are $18,000. Her pension is $20,000 on Form 1099-R, box 1, and she made no after-tax contributions. She also has $1,000 of taxable interest.

Step 1: Other income is $20,000 + $1,000 = $21,000.

Step 2: Half of her benefits is $9,000. Her combined income is $21,000 + $9,000 = $30,000.

Step 3: $30,000 is above the $25,000 base but not above $34,000, so the 50% rule applies.

Step 4: Taxable Social Security is the smaller of two amounts: 50% of benefits ($9,000), or 50% of combined income above the base ($30,000 − $25,000 = $5,000, times 50%, which is $2,500). The taxable amount is $2,500.

Step 5: Income before deductions is $20,000 + $1,000 + $2,500 = $23,500. Maria then subtracts the 2026 standard deduction for a single filer, $16,100, and the additional amount for being 65 or older and unmarried, $2,050. That leaves $5,350 of taxable income before any other deductions or credits she may qualify for (the Form 1040 instructions list them) and before the tax is figured.

What is the most common mistake?

The most common mistake is using the gross benefit amount from Box 3 instead of the net amount in Box 5, or assuming all Social Security is taxable, or none of it is, without running the combined income test. The test is the step that decides it.

What should I do next?

1. Run your combined income using Box 5 of each Form SSA-1099 or RRB-1099.
2. Check each Form 1099-R for the total in box 1 and the taxable amount, if one is shown.
3. Add any taxable interest or dividends, and any tax-exempt interest, which counts in combined income.
4. If you want tax taken out of your benefits, you can ask the Social Security Administration to withhold federal income tax using Form W-4V (Publication 915).

A checklist for retirement income

• Form SSA-1099 or RRB-1099, with Box 5 noted
• Every Form 1099-R, with box 1 and any taxable amount
• Forms 1099-INT and 1099-DIV, plus tax-exempt interest
• Your annual statement from your my Social Security account, to confirm the benefit total
• Any after-tax contribution records for the pension

See how it works.

Sources: IRS Publication 915, Social Security and Equivalent Railroad Retirement Benefits (2025 edition), Base amount, combined income, Worksheet 1 and Form SSA-1099 Box 5; IRS Publication 17 (2025 edition), chapter 7 (Social Security benefits and Worksheet 7-1) and chapter 11 (pensions); Form 1040 and 1040-SR instructions, lines 5a, 5b, 6a and 6b (2025 edition); Publication 939, General Rule and Simplified Method; Revenue Procedure 2025-32, sections .14 (2026 standard and additional standard deduction). This is general information, not advice about your specific return.

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