Line 23 — Other Taxes from Schedule 2

Line 23 on your Form 1040 is the line labeled other taxes, and it is not a number you write in by hand. It carries straight over from Schedule 2, line 21. Schedule 2 is the worksheet where the IRS gathers every tax you owe that is not the plain income tax on your taxable income. Part I of Schedule 2 handles the alternative minimum tax and the repayment of advance premium tax credit, and those feed an earlier line. Part II is the part that lands on form 1040 line 23 other taxes, and that is where the real surprises tend to live. If you have never looked closely at Schedule 2 before, this is the year to start, because it explains a lot of the bottom-line shock people feel in April when the total comes in higher than the income tax they were watching all year.

Think of your tax return as having two layers. The first layer is the income tax that the IRS calculates on your wages, your business profit, your dividends, and the rest of your taxable income. That income tax shows up on line 16 and gets adjusted by your credits down through line 22. The second layer is everything else the law says you owe. Self-employment tax sits in this layer. The extra Medicare tax for high earners sits here. The net investment income tax sits here. The penalty for pulling money out of a retirement account before you are allowed to sits here too. All of those get totaled on Schedule 2 Part II, and the sum becomes your line 23 figure. The income tax brackets you hear about on the news never touch any of these. They are a different animal entirely, governed by their own rules and their own thresholds.

What trips people up is the order of operations on the form. Your credits, the child tax credit, the education credits, the foreign tax credit, all of those reduce the income tax in the first layer and nothing more. They do nothing to the second layer. So a person who zeroes out their income tax with credits can still owe a very real bill, because the other taxes on line 23 are sitting underneath, untouched and waiting. We see this every single filing season with new business owners who assumed a credit they were counting on would cover the whole thing. It almost never does, and the gap is usually self-employment tax that grew right alongside their good year.

The clean way to read your own return is to find line 22, which is your tax after credits, then find line 23, then look at line 24, which adds the two together for your total tax. Line 24 is the real number, the one the IRS compares against what you already paid in. If line 23 is large and you did not plan for it, that gap is almost always self-employment tax or an investment income tax you did not realize applied to you. The full breakdown of what belongs on each Schedule 2 line is spelled out in the Schedule 2 instructions, and the Form 1040 instructions walk through how line 23 rolls into line 24. If you want a real person to map this out against your actual numbers before April rather than after, our individual tax return team does exactly that for clients across New York City. Reading these three lines in order, 22 then 23 then 24, gives you a fast sanity check on whether your return makes sense before you sign it, and it is the easiest way to catch a missing form before the IRS catches it for you. Most people who get a notice about line 23 were not hiding anything, they just never knew the line existed or what fed it, and a two-minute look at these numbers each year would have saved them the letter and the worry that comes with it.

Quite a few items can land on form 1040 line 23 other taxes, and most filers only ever see one or two of them in any given year. The biggest one for self-employed people is self-employment tax, figured on Schedule SE. This is the Social Security and Medicare tax that a regular employee splits with an employer. When you work for yourself, you are both the worker and the boss, so you pay both halves. It runs 15.3 percent on the first chunk of net earnings and 2.9 percent above the Social Security wage base. That total flows into Schedule 2 and then onto line 23, which is why a profitable freelance year can produce a tax bill that feels out of proportion to the income tax alone.

Next is the Additional Medicare Tax of 0.9 percent. It applies to earned income over 200,000 dollars if you are single and 250,000 dollars if you are married filing jointly. You calculate it on Form 8959, and the result joins the line 23 stack. Then there is the Net Investment Income Tax, a flat 3.8 percent on investment income such as interest, dividends, capital gains, and rental income, once your modified adjusted gross income passes those same thresholds. That one runs through Form 8960 and also feeds line 23. The two share thresholds but hit different kinds of money, one your labor and one your portfolio, so it is common for a high earner with an investment sale to owe both in the same year and feel doubly stung by it.

The list keeps going from there. If you took money out of a retirement plan before age 59 and a half, the 10 percent additional tax on early distributions shows up here. Household employment taxes, what most people call the nanny tax, get reported on Schedule H and flow through to this line if you paid a household worker enough to owe Social Security and Medicare on their wages. Repayment of excess advance premium tax credit, the subsidy reconciliation from a marketplace health plan, can land here as well when your income came in higher than the estimate you gave the exchange. There are a handful of smaller items too, such as recapture of certain credits and the tax on an HSA distribution that was not used for medical costs.

The common thread is that none of these are the regular income tax. They are separate charges Congress attached to specific situations, and they all get herded onto Schedule 2 Part II so they can be added to your bill in one place. That is why a return with a modest income tax can still produce a heavy line 23. A freelancer with a good year might owe almost nothing in income tax after the standard deduction, yet owe several thousand dollars in self-employment tax that nobody warned them about. If you have several of these pieces moving at once, the math gets layered fast.

One last thing worth knowing about this line is that the items on it tend to cluster. The same person who owes self-employment tax is often the same person whose business pushed their income over the Additional Medicare Tax threshold, and a strong year for the business is frequently a strong year for the portfolio too. So once one of these other taxes appears on your return, it pays to check whether the others are quietly riding along beside it. We handle returns where self-employment tax, the extra Medicare tax, and the investment income tax all hit the same client in the same year. Getting each form right matters, because an error on Form 8959 or Schedule SE flows straight to line 23 and changes the total on line 24. You can read the official IRS descriptions of each form through the links above, and our individual tax preparation service can run your numbers through every one of them so nothing gets missed.

This is the part that catches the most people off guard, so it is worth being blunt about it. Nonrefundable credits do not touch the other taxes on form 1040 line 23 other taxes. They never have, and the way the Form 1040 is built, they never will. The form puts credits in one zone and other taxes in a completely different zone, and the two simply do not cross. A lot of confusion comes from people thinking of tax as one big pot that any credit can chip away at. It is not. There are walls between the sections, and line 23 sits on the far side of the wall from your credits, out of their reach no matter how many you stack up.

Here is how it actually works on the form. Your income tax sits on line 16. Then your credits, things like the child tax credit, the credit for other dependents, education credits, and the foreign tax credit, get applied through Schedule 3 and reduce that income tax down to line 22, which is your tax after credits. Line 22 can go all the way to zero if you have enough credits. But line 23 sits below line 22, and it is added on top of it. So even if credits wiped out every dollar of your income tax, the self-employment tax and any investment income tax on line 23 stay exactly where they are. Line 24, your total tax, is line 22 plus line 23. The credits did their work above the line, and line 23 lives below it, untouched.

The reason is policy, not an accident of form design. Self-employment tax funds your future Social Security and Medicare benefits. Congress did not want general tax credits letting people opt out of paying into those programs, so it placed self-employment tax outside the reach of the credits on purpose. The same logic applies to the Additional Medicare Tax and the Net Investment Income Tax, both figured on their own forms and both immune to your credits. They are funding mechanisms tied to specific revenue purposes, and letting an education credit erase them would defeat the whole point of having them in the first place.

This is also why tax planning for the self-employed and for high earners looks different from planning for a wage employee. A W-2 employee can sometimes credit their way down to a small final bill. A freelancer cannot credit away the self-employment tax, full stop. The only ways to move that number are to reduce net self-employment earnings through legitimate business deductions, or in some cases to restructure the business so that not all profit is subject to self-employment tax. Those are real strategies with real tradeoffs, and they have to be set up correctly during the year, not improvised at filing time. The mistake we see over and over is a client who runs the numbers in their head, counts on a credit they are expecting, and assumes the bottom line will be small. Then the return comes back with a four-figure line 23 that the credit never touched.

If you want to understand what your other taxes will actually be and whether anything can be done about them, that is a conversation worth having before December. Our tax strategy consulting looks at exactly this, and the Schedule 2 instructions confirm where each item lands. The practical takeaway is to stop thinking of credits as a cushion against your whole tax bill. They are a cushion against your income tax only. A married couple with two kids and a freelance side business can have a child tax credit that erases their income tax entirely and still write a check in April for the self-employment tax on that side income. Once you see the two layers clearly, the bill stops being a mystery and starts being something you can plan around.

Numbers make this concrete, so here is a realistic case. Picture a freelance graphic designer who is also married to a high-earning spouse. The designer had a strong year and netted enough profit that her self-employment tax, figured on Schedule SE, comes to 7,000 dollars. That 7,000 dollars is not income tax. It is the Social Security and Medicare she owes as her own employer, the cost of working for herself instead of for a company that would have split the bill with her. It flows into Schedule 2 Part II, where the other taxes get collected before they move to the main form.

Now add the household side of the picture. Their combined earned income pushes them over the 250,000 dollar married filing jointly threshold for the Additional Medicare Tax. On the earnings above that line, the extra 0.9 percent kicks in, and on Form 8959 it works out to 1,000 dollars. That 1,000 dollars also flows into Schedule 2 Part II. So now Schedule 2 holds 7,000 plus 1,000, which is 8,000 dollars, and that total carries to form 1040 line 23 other taxes. Two separate forms, two separate taxes, one combined number sitting on line 23 waiting to be added to everything else.

Here is where the structure bites. Suppose this couple also qualifies for credits that bring their income tax, line 22, down to a small figure, say 2,000 dollars after the credits do their work. A lot of people would look at that 2,000 and feel relieved, thinking the hard part is behind them. But line 23 is sitting right below it at 8,000 dollars, completely unaffected by anything the credits did. Line 24, the total tax, is line 22 plus line 23, which is 2,000 plus 8,000, or 10,000 dollars. The credits cut the income tax but did nothing to the 8,000 on line 23. The real bill is five times what they were bracing for, and not one dollar of that difference came from the income tax they were watching all year.

If they had withholding and estimated payments covering only the 2,000 dollar income tax, they now owe 8,000 dollars at filing, possibly with an underpayment penalty on top, because the IRS expected those other taxes to be paid in during the year as the income was earned. This is the exact scenario that turns a calm April into a scramble, and it happens to smart, careful people who simply did not know line 23 worked this way. The fix is not complicated, it just has to happen early. Once you know self-employment tax and the Additional Medicare Tax are coming, you build them into your quarterly estimated payments so the cash is set aside as you earn it instead of all at once in spring. Even a rough quarterly payment beats nothing, because it shrinks both the lump sum due in April and any penalty the IRS would otherwise tack on for paying late.

A designer pulling in steady freelance income can usually estimate her self-employment tax within a few hundred dollars by midyear if her records are current. Clean books make that estimate far easier, which is one reason we push clients toward solid bookkeeping rather than a shoebox of receipts in March. The mechanics of each form are confirmed in the Form 1040 instructions. The broader lesson from this example is that your final tax bill is the sum of two very different calculations, and the one most people ignore is usually the larger of the two for a self-employed household. In this case the income tax was 2,000 dollars and the other taxes were 8,000 dollars, four times bigger. Watch line 23, set money aside for it through the year, and the total on line 24 stops being a shock.

The single most common mistake is budgeting only for income tax and treating form 1040 line 23 other taxes as an afterthought, if it gets thought about at all. People hear the word tax and picture the brackets on their taxable income, the percentages everyone talks about. They forget that self-employment tax and the investment income taxes are a separate charge that the brackets never touch. So they set aside money for income tax, file the return, and get blindsided by a line 23 figure that doubles or even triples what they expected to owe. The money was earned, the work was real, but the tax on it never made it into the mental budget anyone was keeping.

The version of this mistake that hurts the most is the credit assumption. Someone has a child tax credit or an education credit coming and tells themselves the credit will cover the whole bill. It will not. As covered in the question above, credits reduce the income tax on Form 1040 down to line 22, but line 23 sits below them and is added on top through Schedule 2. A credit can take your income tax all the way to zero and you can still owe several thousand dollars of self-employment tax on the very same return. The credit and the self-employment tax never meet on the form, so counting on one to cancel the other is wishful math.

The second flavor is the new freelancer who never made estimated payments. A wage employee has tax withheld from every paycheck, including the Medicare and Social Security portions, so by the time the return is filed most of the bill is already paid. The freelancer has nothing withheld from anything, so the full self-employment tax from Schedule SE shows up all at once on line 23 at filing time. Worse, the IRS charges an underpayment penalty for not paying it in quarterly across the year. The first year out on your own is where this lands hardest, because nobody handed you a memo explaining that the quarterly system exists or that you are now responsible for it.

A third version shows up for people whose investment income crosses the threshold for the first time. They sell a property or a large block of stock, the Net Investment Income Tax at 3.8 percent kicks in, and it appears on line 23 with no warning attached to the sale itself. The Additional Medicare Tax on Form 8959 can do the same thing in a year with a big bonus or an unusually strong business year. Avoiding all of this comes down to one habit. Treat line 23 as its own number, separate from your income tax, and estimate it before the year closes while you still have room to act on it.

If you are self-employed, that means knowing your net profit by the fall and paying quarterly. If you are a high earner, it means checking whether you crossed the 200,000 or 250,000 thresholds. Good records make the estimate honest, which is why we tie tax planning to ongoing bookkeeping for our business clients across New York City. The people who never get burned by this line are not smarter than everyone else, they just look at it on purpose every year. They know roughly what their self-employment tax will be, they know whether they are near the high-earner thresholds, and they pay it in as they go. The people who do get burned are the ones who only ever look at the income tax and let line 23 ambush them at filing time. The difference between those two groups is a single hour of planning in the fall, and it is the easiest hour of tax work you will ever do.