Form 1040 Line 16: How Your Tax Is Calculated

Line 16 of Form 1040 is your federal income tax for the year, calculated from the taxable income figure directly above it on Line 15. The IRS applies the progressive tax brackets to that Line 15 amount, and the resulting dollar figure goes on Line 16.¹ If part of your income is long-term capital gains or qualified dividends, a separate worksheet handles those at lower rates before the total lands on the same line.

What Line 15 Feeds Into Line 16

Line 16 only makes sense once you know how Line 15 got there. Taxable income is built through a specific chain of subtractions:

Start with gross income (wages, interest, dividends, business profit, capital gains, retirement distributions, and anything else the IRS doesn’t specifically exclude).
Subtract above-the-line adjustments from Schedule 1 to reach Adjusted Gross Income on Line 11.²
Subtract your standard deduction or itemized deductions on Line 12.
Subtract the Qualified Business Income deduction on Line 13a, if you have pass-through business income.
Subtract the new Schedule 1-A deductions on Line 13b (tip income, overtime pay, auto loan interest, and the enhanced senior deduction introduced by the One, Big, Beautiful Bill).

Line 14 combines Lines 12, 13a, and 13b. That total is subtracted from AGI on Line 11 to produce taxable income on Line 15.¹ If the math produces zero or a negative number, you enter zero. A negative result doesn’t create a refund on its own; refundable credits elsewhere on the return do that work.

How the Tax on Line 16 Is Calculated

Once you have Line 15, there are two standard ways to get to Line 16.

Filers with taxable income below $100,000 use the IRS Tax Tables, which give a specific dollar amount for each $50 income range.³ You find your filing status column, locate your income row, and copy the number to Line 16.

Filers with taxable income of $100,000 or more use the Tax Computation Worksheet, which applies the marginal rates directly.

Either way, the underlying rate structure is the same. Federal income tax is progressive: each slice of your income is taxed at the rate for that bracket, and the total tax is the sum of the slices. A single filer with $90,000 in taxable income pays 10% on the first $12,400, 12% on the portion up to $50,400, and 22% on the rest. The effective rate ends up lower than the top marginal rate the income touched.

2026 Federal Tax Brackets

For tax year 2026, the marginal rates and thresholds for single filers and married couples filing jointly are:⁴

10%: Up to $12,400 (single) / $24,800 (joint)
12%: $12,401 – $50,400 (single) / $24,801 – $100,800 (joint)
22%: $50,401 – $105,700 (single) / $100,801 – $211,400 (joint)
24%: $105,701 – $201,775 (single) / $211,401 – $403,550 (joint)
32%: $201,776 – $256,225 (single) / $403,551 – $512,450 (joint)
35%: $256,226 – $640,600 (single) / $512,451 – $768,700 (joint)
37%: Over $640,600 (single) / Over $768,700 (joint)

When Capital Gains and Qualified Dividends Change the Math

If any of your income is long-term capital gains or qualified dividends, you don’t use the tax tables or the standard worksheet alone. You use the Qualified Dividends and Capital Gain Tax Worksheet, which pulls those items out and taxes them at preferential rates before combining everything back into a single Line 16 figure.²

The preferential rates are 0%, 15%, and 20%, tied to taxable income:

0%: Taxable income up to $49,450 (single) / $98,900 (joint)
15%: $49,451 to $545,500 (single) / $98,901 to $613,700 (joint)
20%: Above $545,500 (single) / $613,700 (joint)

The worksheet calculates ordinary-income tax at the regular bracket rates, then adds the capital gains and dividend tax at the preferential rates. That combined total is what goes on Line 16. Two filers with identical taxable income can owe different amounts on Line 16 because the composition of the income matters, not just the sum.

Other Amounts That Can Land on Line 16

A few less common items also flow into Line 16.

Form 8814 covers parents who elect to report a child’s investment income on their own return instead of filing a separate return for the child. A child’s unearned income above $2,700 is taxed at the parent’s marginal rate, and parents can pull it onto their return if the child’s total gross income is under $13,500.⁵

Form 4972 handles the special tax treatment available for certain lump-sum distributions from qualified retirement plans. If either applies to you, the resulting tax gets added into the Line 16 figure.

What Line 16 Does Not Include

Line 16 is your regular income tax. It isn’t the last stop on the return, and it isn’t your entire federal tax bill.

Line 17 pulls in amounts from Schedule 2, including the Alternative Minimum Tax and excess advance premium tax credit repayments. Line 18 sums Lines 16 and 17.¹ The AMT is a parallel calculation that disallows certain deductions and applies a flatter rate structure; if it produces a higher number than your regular tax, you owe the difference. For 2026, the AMT exemption is $90,100 for single filers and $140,200 for joint filers, with phase-outs at higher incomes.⁴

Higher-income filers with investment income may also owe the 3.8% Net Investment Income Tax on the lesser of their net investment income or the amount by which modified AGI exceeds $200,000 (single) or $250,000 (joint).⁶ The NIIT is calculated separately, reported through Schedule 2, and shows up on Line 23, not Line 16. Self-employment tax, additional Medicare tax, early-withdrawal penalties on retirement accounts, and household employment taxes also come in through Schedule 2 rather than Line 16.

So if your Line 16 figure looks lower than what you expected to owe, check the lines below it. The total tax number you actually owe or reconcile against withholding is on Line 24.

Quick Check Before You File

Two errors are easy to make on Line 16. The first is using the tax tables when you should have used the Qualified Dividends and Capital Gain Tax Worksheet, which almost always produces a lower tax when preferential-rate income is present. The second is using the tables at all when Line 15 is $100,000 or more; above that threshold, the Tax Computation Worksheet is required.³ If you’re using tax software, both routes are handled automatically, but it’s worth confirming the method used matches the income on your return.

1
Internal Revenue Service. Form 1040
2
Internal Revenue Service. Instructions for Forms 1040 and 1040-SR
3
Internal Revenue Service. 2025 Publication 1040 – Tax Tables
4
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One, Big, Beautiful Bill
5
Internal Revenue Service. Topic No. 553, Tax on a Child’s Investment and Other Unearned Income (Kiddie Tax)
6
Internal Revenue Service. Topic No. 559, Net Investment Income Tax