Schedule 2 (Form 1040) 2026: Additional Taxes Explained Line by Line

On Schedule 2 (Form 1040), the Additional Medicare Tax goes on Part II, Line 11 (calculated on Form 8959) and the net investment income tax goes on Part II, Line 12 (calculated on Form 8960). Those two surtaxes join self-employment tax on Line 4, and the Part II total on Line 21 lands on Form 1040, Line 23. Every line reference in this guide is checked against the 2025 revision of Schedule 2, the version filed during the 2026 filing season.

Key takeaways:

• Line 11 = Additional Medicare Tax: 0.9% on wages and self-employment income above $200,000 single / $250,000 married filing jointly (Form 8959, Line 18 carries the total here)
• Line 12 = Net investment income tax (NIIT): 3.8% on investment income once modified AGI passes the same thresholds (Form 8960)
• Line 4 = self-employment tax (15.3%, from Schedule SE); Line 21 totals Part II and flows to Form 1040, Line 23, after credits, so credits never reduce it
• Line 3 (Part I total) carries AMT plus premium-tax-credit repayment to Form 1040, Line 17, before credits
• Both surtax thresholds have been frozen since 2013; they are not indexed for inflation

Official IRS resources: Schedule 2 (Form 1040) (PDF) · Form 1040 Instructions (PDF) · About Form 1040

What Is Schedule 2?

Schedule 2 (officially "Additional Taxes") is an attachment to Form 1040, 1040-SR, or 1040-NR. It has two parts, and each part produces one total:

• Part I (Tax) reports the alternative minimum tax and the repayment of excess advance Premium Tax Credit. The Part I total (Line 3) flows to Form 1040 Line 17.
• Part II (Other Taxes) reports self-employment tax, the Additional Medicare Tax, the net investment income tax, household employment taxes, extra taxes on retirement accounts, and a long list of recapture items. The Part II total (Line 21) flows to Form 1040 Line 23.

The split matters. Part I taxes are added before nonrefundable credits on Form 1040, so credits can wipe them out. Part II taxes are added after credits, near the bottom of the return — credits do not reduce them. That's why self-employment tax keeps showing up even when income tax drops to zero.

Legal basis: IRC §55 (alternative minimum tax), IRC §1401 (self-employment tax), IRC §3101 (Medicare and the 0.9% Additional Medicare Tax), and IRC §1411 (net investment income tax). The form itself is built from the Form 1040 instructions and the specific instructions for each attached form.

Who Files Schedule 2?

You file Schedule 2 if any of these apply:

• You owe self-employment tax (Schedule SE → Part II)
• Your wages or self-employment income cross the Additional Medicare Tax threshold (Form 8959)
• You have investment income and your AGI clears the net investment income tax threshold (Form 8960)
• You owe alternative minimum tax (Form 6251)
• You received advance Premium Tax Credit and must repay part of it (Form 8962)
• You paid a household employee enough to owe employment taxes (Schedule H)
• You took an early or non-qualified distribution from an IRA, HSA, or other tax-favored account (Form 5329 or Form 8889)
• You owe one of the recapture or excise taxes listed in Part II

You skip Schedule 2 entirely if your only tax is ordinary income tax and you have no W-2 wages high enough to trigger the Medicare surtax. Most pure-W-2 filers under the thresholds never touch it. Most self-employed filers attach it every year because of Line 4.

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Schedule 2 Line Map: Which Tax Goes on Which Line

The form structure is fixed by the IRS. Part I covers Lines 1-3. Part II covers Lines 4-21. The table below matches the 2025 revision of Schedule 2 (the return filed in 2026) and shows which tax sits in which part, the rate or threshold where one applies, and the form you attach.

Two thresholds you need to memorize. The Additional Medicare Tax (0.9%) and the net investment income tax (3.8%) both kick in at $200,000 for single filers, $250,000 for married filing jointly, and $125,000 for married filing separately. These thresholds are not indexed for inflation — they have been frozen since 2013 and stay the same for 2026. More taxpayers cross them every year as wages rise, which is exactly the point.

AMT exemption (2026). For tax year 2026 the AMT exemption is $90,100 for unmarried individuals (phaseout begins at $500,000) and $140,200 for married filing jointly (phaseout begins at $1,000,000). These figures come from Rev. Proc. 2025-32 and reflect changes from the One Big Beautiful Bill Act, which also steepened the phaseout: the exemption now shrinks by 50 cents per dollar of AMT income above the threshold, up from 25 cents through 2025. The 2025 figures were $88,100 single / $137,000 MFJ for reference.

Legal basis: IRC §55, §1401, §3101, §1411; IRS Form 1040 instructions; Form 8959, Form 8960, and Form 6251 instructions.

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Part I: Tax (Line by Line)

Part I holds two true taxes plus a set of credit-repayment lines. These are added near the top of Form 1040, so nonrefundable credits can offset them.

Line 1: Additions to Tax (1a through 1z)

Line 1 is a block of repayment and recapture entries that the IRS groups together:

Line 1a is the one most individuals hit. If you bought marketplace health coverage and the exchange paid an advance Premium Tax Credit on your behalf, and your actual income ended up higher than estimated, you repay the excess here. Form 8962 reconciles the advance credit against the credit you actually qualified for. A mid-year raise or a strong freelance quarter is the usual cause.

Line 2: Alternative Minimum Tax

The AMT is a parallel tax system. You calculate your tax twice — once under the regular rules, once under AMT rules on Form 6251 — and pay whichever is higher. The AMT adds back certain preference items, applies the exemption ($90,100 single / $140,200 MFJ for 2026), and taxes the result at 26% or 28%.

For most self-employed filers and middle-income households, AMT does not apply — the exemption is high and the One Big Beautiful Bill Act kept it elevated. AMT tends to surface with large incentive stock option exercises, significant private-activity-bond interest, or very high state-tax addbacks. If Form 6251 produces a number larger than your regular tax, the difference lands on Line 2.

Legal basis: IRC §55.

Line 3: Part I Total

Add Line 1z and Line 2. The result flows to Form 1040 Line 17, where it joins your regular income tax before nonrefundable credits are subtracted.

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Part II: Other Taxes (Line by Line)

Part II is the bigger and, for self-employed filers, the more important part. These taxes sit near the bottom of Form 1040 and credits do not reduce them.

Line 4: Self-Employment Tax

The headline line for anyone self-employed. This is the 15.3% Social Security and Medicare tax on net self-employment earnings, calculated on Schedule SE and carried to Line 4. The rate breaks into 12.4% Social Security (capped at the wage base) and 2.9% Medicare (no cap).

You can check a box for an approved exemption (Form 4361 for certain ministers, Form 4029 for certain religious sects), but those are rare. For the full calculation — the 0.9235 factor, the wage base, the half-SE-tax deduction — see our Schedule SE Instructions Guide 2026.

Legal basis: IRC §1401, §1402.

Lines 5-7: Social Security and Medicare Tax on Tips and Uncollected Wages

• Line 5: Social Security and Medicare tax on unreported tip income, from Form 4137. For tipped workers whose employer didn't withhold on all reported tips.
• Line 6: Uncollected Social Security and Medicare tax on wages, from Form 8919. Used when you were treated as an independent contractor but the IRS determined you were an employee.
• Line 7: Adds Lines 5 and 6.

Most solo business owners leave these blank.

Line 8: Additional Tax on IRAs or Other Tax-Favored Accounts

The penalty for early or improper retirement and savings-account activity, generally 10%, calculated on Form 5329. The most common trigger is an early distribution from a traditional IRA or 401(k) before age 59½. If Form 5329 isn't otherwise required, you can check the box and enter the penalty directly. Legal basis: IRC §72(t) (early distributions), §4973-§4974 (excess contributions and missed RMDs).

Line 9: Household Employment Taxes

If you paid a nanny, housekeeper, or other household employee above the annual threshold, you owe Social Security, Medicare, and federal unemployment taxes on those wages. Schedule H calculates them and the total lands on Line 9. This is the "nanny tax."

Line 10: Reserved for Future Use

Currently blank on the 2025 revision of the form. For years, Line 10 carried the annual repayment of the 2008 first-time homebuyer credit (Form 5405). That credit was repaid over 15 years, and the final installment posted on the 2024 return — so there is no 2025 or 2026 installment, and the IRS reserved the line. If you still have a homebuyer-credit recapture event (you sold or stopped using the home), check the current Form 5405 and Form 1040 instructions for the exact reporting line on the year you file.

Line 11: Additional Medicare Tax (Form 8959)

Schedule 2, Line 11 reports the Additional Medicare Tax: a 0.9% surtax on wages, Railroad Retirement (RRTA) compensation, and self-employment income above the threshold for your filing status. You calculate it on Form 8959, which figures the surtax separately on wages (Part I), self-employment income (Part II), and RRTA compensation (Part III), then totals the three on Form 8959, Line 18. That Line 18 total is the number you enter on Schedule 2, Line 11.

Thresholds (not indexed for inflation):

The surtax applies only to the income above the threshold. Employers must withhold the extra 0.9% on wages over $200,000 regardless of filing status, which can over- or under-withhold depending on your spouse's income; Form 8959 trues it up. Legal basis: IRC §3101(b)(2) and §1401(b)(2).

Line 12: Net Investment Income Tax (Form 8960)

Schedule 2, Line 12 reports the net investment income tax (NIIT): a 3.8% tax on net investment income, meaning interest, dividends, capital gains, rental and royalty income, and passive business income, calculated on Form 8960. It applies to the lesser of your net investment income or the amount by which your modified AGI exceeds the threshold.

Thresholds (identical to the Medicare surtax, also not indexed): $200,000 single, $250,000 MFJ, $125,000 MFS.

The two surtaxes never hit the same dollar. The 0.9% Medicare tax hits earned income (wages and SE income); the 3.8% NIIT hits investment income. A high earner with a large brokerage account can owe both, on different income. Legal basis: IRC §1411.

What the NIIT does NOT tax: HSA distributions

Health savings account (HSA) distributions do not go on Form 8960. The Form 8960 instructions define net investment income as interest, dividends, annuities, royalties, rents, and gains, and nothing in the line-by-line instructions (including Line 7, "other modifications to investment income," which handles items like §1411 net operating losses) directs an HSA distribution onto the form. Two caveats keep people confused:

• A taxable (non-qualified) HSA distribution is included in gross income, so it raises your modified AGI. That can push you over the $200,000 / $250,000 threshold and expose more of your other investment income to the 3.8% tax, even though the distribution itself is never taxed as NII.
• The 20% additional tax on a non-qualified HSA distribution is a separate Schedule 2 item: it flows from Form 8889 to Line 17c, not through Form 8960.

Earnings inside an HSA (interest and dividends the account generates) are also outside the NIIT while they stay in the account.

Lines 13-20: Recapture, Deferred Installment, and Excise Taxes

These lines are narrow and most filers skip them:

Line 17c-17d matters to HSA holders. If you took a non-qualified HSA distribution (spent HSA money on non-medical expenses), the 20% additional tax is reported in the Line 17 block via Form 8889, not on Line 8. For the rules on qualified vs. non-qualified HSA spending, see our Form 8889 HSA guide.

Line 21: Part II Total

Add Lines 4, 7 through 16, 18, and 19. (Lines 5, 6, and 17 feed subtotals on Lines 7 and 18, so they aren't added again; Line 20 is a separate installment line per the instructions.) This is your total other taxes, and it flows to Form 1040 Line 23.

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How Schedule 2 Flows Into Form 1040

The two totals land in two specific places: Schedule 2, Line 3 goes to Form 1040, Line 17 (added before credits), and Schedule 2, Line 21 goes to Form 1040, Line 23 (added after credits). Here is the full sequence on the 2025 Form 1040:

Part I taxes (Line 17) come before the credit lines, so the Child Tax Credit or education credits can absorb them. Part II taxes (Line 23) come after, so they survive every credit. That single structural fact explains why a freelancer with two kids can zero out income tax and still owe several thousand dollars in self-employment tax. For the full walk-through of the parent form, see our Form 1040 guide.

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Worked Example: Priya, a Freelancer Crossing the Medicare Surtax Line

Priya is a single freelance software consultant. She had a strong 2026:

• Schedule C net profit: $230,000
• No W-2 wages, no investment income above ordinary dividends
• Filing status: single (threshold $200,000)

Step 1: Self-employment tax (Schedule SE → Line 4)

Priya's Social Security base stops at the $184,500 cap, the 2026 Social Security wage base ($176,100 for 2025), while Medicare keeps running on the full $212,405. (For the line-by-line of this calculation, see the Schedule SE guide.)

Step 2: Additional Medicare Tax (Form 8959 → Line 11)

The 0.9% surtax applies to self-employment income above $200,000. Form 8959 measures it against the reduced (0.9235) SE base:

Step 3: Priya's Schedule 2

What this means for Priya

Priya's regular income tax is calculated separately on Form 1040 Line 16. Whatever credits she claims reduce that income tax, but they do not touch the $29,150 on Line 23. She also deducts half of her self-employment tax ($14,519) as an above-the-line adjustment on Schedule 1, which lowers her income tax but not the SE tax itself.

The lesson: Priya needed to set aside roughly 13% of her net profit for the Schedule 2 stack alone, on top of income tax. The $112 Additional Medicare Tax is small here, but it grows fast as income climbs above $200,000.

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Common Mistakes to Avoid

Mistake #1: Assuming Credits Erase Self-Employment Tax

Problem: A filer with two kids assumes the Child Tax Credit zeroes out everything they owe.

Impact: The Child Tax Credit reduces income tax (above Line 22). Self-employment tax on Line 23 sits below it and survives. The filer gets a surprise balance due of several thousand dollars.

Solution: Treat Part II taxes as a separate, credit-proof obligation. Budget for them independently.

Mistake #2: Forgetting the Additional Medicare Tax When Both Spouses Work

Problem: Each spouse earns $150,000. Neither employer withholds the 0.9% surtax (each is under the $200,000 individual withholding trigger), but their combined $300,000 exceeds the $250,000 MFJ threshold.

Impact: $50,000 × 0.9% = $450 owed at filing with no withholding to cover it.

Solution: Run Form 8959 if household earned income clears the MFJ threshold. The thresholds are not indexed, so more dual-income couples cross them each year.

Mistake #3: Missing the Net Investment Income Tax After a Big Capital Gain

Problem: A filer sells appreciated stock or a rental property, pushing modified AGI well over $200,000, and reports only the capital gains tax.

Impact: The 3.8% NIIT on Form 8960 applies to the investment income above the threshold and is owed in addition to the capital gains rate.

Solution: Any year with a large gain, dividend windfall, or rental profit, check whether modified AGI clears the threshold and complete Form 8960.

Mistake #4: Putting Non-Qualified HSA Distributions on the Wrong Line

Problem: A filer who spent HSA funds on non-medical expenses enters the 20% additional tax on Line 8 (IRAs).

Impact: Mismatched line; the IRS expects the HSA penalty in the Line 17 block via Form 8889.

Solution: Line 8 is for IRA/retirement penalties (Form 5329). HSA non-qualified distribution tax flows through Form 8889 into Line 17. See our Form 8889 guide.

Mistake #5: Repaying the Wrong Amount of Advance Premium Tax Credit

Problem: A self-employed filer with marketplace coverage underestimates income, takes a large advance Premium Tax Credit, then earns more, and forgets to reconcile on Form 8962.

Impact: The unreported excess advance credit shows up as an IRS adjustment on Line 1a, often with a notice.

Solution: Reconcile every year on Form 8962. If income rose, expect a repayment on Schedule 2 Line 1a and plan for it.

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Action Checklist: Filing Schedule 2

Before Tax Time

• Confirm whether you owe self-employment tax (any net SE earnings of $400+)
• Add up all earned income to test the $200,000 / $250,000 Additional Medicare Tax threshold
• Total investment income and check modified AGI against the NIIT threshold
• Gather Form 1095-A if you had marketplace coverage (needed for Form 8962)
• Note any early retirement-account or non-qualified HSA distributions

At Tax Time

• Complete Schedule SE first, then carry the result to Schedule 2 Line 4
• Run Form 8959 if earned income clears the Medicare surtax threshold → Line 11
• Run Form 8960 if AGI clears the NIIT threshold → Line 12
• Complete Form 6251 to test for AMT → Line 2
• Reconcile advance Premium Tax Credit on Form 8962 → Line 1a
• Verify Line 3 → Form 1040 Line 17 and Line 21 → Form 1040 Line 23
• Confirm you're using the current-year revision (line numbers shift between years)

Throughout the Year

• Set aside roughly 15% of net SE profit for self-employment tax, separate from income tax
• Include the Schedule 2 stack in quarterly estimated payments
• Track investment sales that could trigger NIIT before year-end

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Resources and Citations

IRS Forms and Instructions

• Schedule 2 (Form 1040): Additional Taxes
• Form 1040 Instructions: General instructions, including Schedule 2 line-by-line
• About Form 1040: IRS landing page with current and prior-year revisions
• Schedule SE (Form 1040): Self-Employment Tax
• Form 8959: Additional Medicare Tax
• Form 8960: Net Investment Income Tax
• Form 6251: Alternative Minimum Tax (Individuals)
• Form 8962: Premium Tax Credit
• Form 5329: Additional Taxes on Qualified Plans (Including IRAs)
• Schedule H: Household Employment Taxes

IRS Guidance Pages

• Net Investment Income Tax: Questions and Answers: confirms 3.8% rate and non-indexed thresholds
• Topic No. 560, Additional Medicare Tax: confirms 0.9% rate and non-indexed thresholds
• IRS 2026 inflation adjustments: 2026 AMT exemption amounts

Tax Code References

• IRC §55: Alternative minimum tax imposed
• IRC §1401: Self-employment tax rate (12.4% Social Security + 2.9% Medicare)
• IRC §1401(b)(2): 0.9% Additional Medicare Tax on self-employment income
• IRC §3101: FICA Medicare tax; §3101(b)(2) is the 0.9% Additional Medicare Tax on wages
• IRC §1411: Net investment income tax (3.8%)
• IRC §72(t): 10% additional tax on early distributions

Related Guides and Tools

• Schedule SE Instructions Guide 2026: full SE tax calculation
• Self-Employment Tax Guide 2026: strategy and planning
• Schedule 1 Guide 2026: where the half-SE-tax deduction lives
• Form 1040 Guide 2026: the parent return
• Self-Employment Tax Calculator: estimate your Line 4 in seconds
• Quarterly Tax Calculator: build the Schedule 2 stack into your estimated payments

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Final Thoughts

Schedule 2 is short, but it carries the taxes that hurt most because nobody withholds for them. Part I (AMT and Premium Tax Credit repayment) sits above the credit lines on Form 1040, so credits can absorb it. Part II (self-employment tax, the 0.9% Medicare surtax, the 3.8% NIIT) sits below them and survives every credit.

Key strategies:

1. Treat Part II as credit-proof: budget for self-employment tax separately from income tax.
2. Memorize the two frozen thresholds: $200,000 single / $250,000 MFJ for both the Medicare surtax and NIIT. They never adjust for inflation.
3. Test for both surtaxes in any high-income or big-gain year: earned income triggers Form 8959; investment income triggers Form 8960.
4. Verify the current revision: line numbers in Part II shift between years (Line 10 is now reserved). Always match the year you file.

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Disclaimer

This article provides general information about Schedule 2 of Form 1040 and should not be considered tax advice. Tax laws change frequently, individual circumstances vary, and inflation-adjusted figures for tax year 2026 are subject to verification against the latest IRS releases and form revisions. For advice specific to your situation, consult with a qualified tax professional.

Tax Year: 2026 Last Updated: July 7, 2026