Why Do I Owe Taxes This Year?

You owe taxes when the tax withheld from your pay during the year is less than the tax you actually owe on your return. A balance due doesn't mean you paid more tax than usual. It means you paid less of it in advance. The most common causes are having two jobs or a working spouse, income with no withholding such as freelance work or investments, a W-4 that no longer matches your situation, and losing a credit or deduction you had the year before.

This guide walks through nine common reasons, with 2026 examples showing how much each one can leave you owing, then covers how to check your withholding mid-year, how to avoid an underpayment penalty, and what to do if you owe more than you can pay right away. Our tax refund estimator shows whether you're on track for a refund or a balance due before you file.

Estimate whether you'll owe or get a refund →

1. You have two jobs

Each employer withholds as if its job were your only income. Each one applies the full standard deduction and starts you at the 10% bracket. Combined, your income reaches higher brackets that neither employer withheld for. A single filer earning $60,000 at one job and $40,000 at another has about $7,640 of federal income tax withheld in total, but owes about $13,170 on $100,000 of combined income. That's roughly $5,530 due at filing.

The fix is Step 2 of Form W-4. Either use the IRS Tax Withholding Estimator, check the box in Step 2(c) on the W-4 for both jobs (which works best when the two pay about the same), or add an extra amount per paycheck in Step 4(c) on one job's W-4.

2. You and your spouse both work

Married couples where both spouses work run into the same problem. If each spouse's W-4 says 'married filing jointly' without completing Step 2, each employer applies the full joint standard deduction and the wide joint brackets to that spouse's pay alone. A couple earning $85,000 and $70,000 would have about $9,880 of federal income tax withheld, but owe about $16,440 jointly: a gap of roughly $6,560.

Completing Step 2 on both W-4s, or checking the 2(c) box on both, corrects it. Couples who married during the year, or where a spouse started working, often see this for the first time.

3. You earned self-employment or side income

Freelance, gig, rideshare and side-business income has no withholding. You owe self-employment tax of 15.3% on 92.35% of net profit, plus income tax at your top bracket. With $12,000 of net side profit on top of a $70,000 job, self-employment tax is about $1,696 and the extra federal income tax about $2,453, after deducting half of the self-employment tax. That's about $4,149 owed on $12,000 of side income, before state tax.

The fix is quarterly estimated payments, due in mid-April, mid-June, mid-September and mid-January, or increasing the withholding at your W-2 job to cover the side income. Setting aside 25% to 30% of each side payment covers most people.

See self-employment tax on $12,000 →

4. Your W-4 is out of date

The W-4 tells your employer how much to withhold. If you claimed dependents in Step 3 and a child turned 17 or moved out, or if you claimed a large deduction in Step 4(b) that no longer applies, your withholding is too low. The same happens after divorce, when someone who had been filing jointly starts filing single or head of household.

Review your W-4 after any major life change: marriage, divorce, a new child, a child aging out of the Child Tax Credit, a new job, or a big change in income. A new W-4 takes effect within a pay period or two.

5. Your bonus or commissions were under-withheld

Bonuses paid separately are usually withheld at a flat 22% federal rate. If your income puts you in the 24% bracket or higher, 22% is too little. A $20,000 bonus for someone in the 24% bracket is under-withheld by about $400; in the 32% bracket, by about $2,000; in the 35% bracket, by $2,600. Large equity vesting events (RSUs) are withheld the same way and are a common source of surprise balances for tech and finance employees.

If you expect large bonuses or stock vesting, add extra withholding through your W-4 or make an estimated payment in the quarter the bonus arrives.

6. You received unemployment or other untaxed income

Unemployment benefits are taxable, and withholding is optional; you have to request it with Form W-4V. Many people don't, and owe tax on those benefits when they file. The same goes for withdrawals from traditional IRAs and 401(k)s where withholding was set to zero, gambling winnings below the reporting thresholds, prizes, alimony from divorces finalized before 2019, and some Social Security benefits.

If you received any of these, check whether tax was withheld. If not, set aside money or make an estimated payment.

7. You had investment income

Interest, dividends and capital gains generally have no withholding. Selling stock, crypto or a fund at a gain, receiving a large year-end mutual fund distribution, or earning more interest as rates rose can all add tax you didn't pay during the year. Long-term gains and qualified dividends are taxed at 0%, 15% or 20%; short-term gains and interest are taxed at your regular rates. Households with income above $200,000 ($250,000 joint) may also owe the 3.8% Net Investment Income Tax.

Brokerage accounts let you request withholding on some payments, but the usual fix is an estimated payment after a large sale.

8. You lost a credit or deduction

Credits that applied last year may not apply this year. A child who turned 17 no longer qualifies for the Child Tax Credit. Higher income can reduce or eliminate the Earned Income Tax Credit, education credits, and the Child Tax Credit for high earners. A dependent who moved out or started supporting themselves may no longer qualify. Paying off a mortgage or student loan removes those deductions.

Losing a credit doesn't change your withholding automatically, because employers don't know about it. If your situation changed, update your W-4 and run the IRS Tax Withholding Estimator.

9. The tips or overtime deduction is smaller than you expected

For 2025 through 2028, qualified tips and the premium part of overtime pay can be deducted from federal taxable income, up to $25,000 for tips and $12,500 ($25,000 joint) for overtime. Payroll withholding doesn't apply these deductions automatically, so most people see them as a larger refund. But if you expected a bigger deduction than you get, because your occupation isn't on the qualifying list, your overtime isn't required under federal law, or your income is in the phase-out range above $150,000 ($300,000 joint), your refund can turn into a balance due.

Our income tax calculator and tax refund estimator both apply the caps and phase-outs, so you can check the real value of these deductions before you file.

Read our no tax on overtime guide →

Avoiding the underpayment penalty

The IRS charges an underpayment penalty, essentially interest, if you didn't pay enough tax during the year through withholding and estimated payments. You generally avoid it if you owe less than $1,000 at filing, or if your payments during the year covered at least 90% of this year's tax or 100% of last year's tax (110% if last year's adjusted gross income was over $150,000).

Withholding counts as if it were paid evenly through the year, no matter when it was taken. That makes increasing withholding late in the year a useful fix: an extra amount withheld from December paychecks counts as if it had been paid all year, while a December estimated payment doesn't cover earlier quarters.

If you owe more than you can pay

File on time even if you can't pay in full, because the penalty for filing late is much larger than the penalty for paying late. Pay what you can by the deadline, then set up an IRS payment plan online. Short-term plans of up to 180 days have no setup fee; long-term installment agreements have a small setup fee and charge interest and a reduced late-payment penalty until the balance is paid.

Then fix the cause for next year using the steps above, so the same balance doesn't come back.

How to check your withholding in five minutes

Take your most recent pay stub. Find the year-to-date federal income tax withheld, then divide it by the number of paychecks so far and multiply by the number of paychecks in the year. That's your projected federal withholding. Next, estimate your total tax for the year: add up all your income, including side income, spouse's pay and investment income, subtract the standard deduction, apply the brackets, and subtract credits such as the Child Tax Credit.

If projected withholding is within a few hundred dollars of your estimated tax, you're on track. If it's well below, divide the gap by the paychecks left in the year and add that amount per check in Step 4(c) of a new W-4. The IRS Tax Withholding Estimator does the same calculation and fills in a W-4 for you. Our tax refund estimator gives a quick check with your income, withholding so far and household details.

Owing state taxes

Everything above applies to state income tax too, often more so. State withholding is calculated from your state W-4 equivalent, and many states have their own form. If you moved states during the year, worked in one state and lived in another, or worked remotely for an employer in a different state, withholding may have gone to the wrong state or been too low in the state where you owe.

Some states tax income the federal government doesn't, such as Pennsylvania taxing 401(k) contributions, or don't follow federal deductions such as the tips and overtime deductions. That can produce a state balance even when your federal return shows a refund.

Is it better to get a refund or owe a little?

A large refund means you overpaid during the year and lent the government money at no interest. Owing a small amount means you kept more of your pay along the way. Financially, the ideal is to be close to zero: a small refund or a small balance due, well under the $1,000 penalty threshold.

That said, some people prefer a refund as forced savings, and there's nothing wrong with that if it's a deliberate choice. What matters is avoiding surprises. If you owed this year, adjust your withholding now so next year's result is the one you planned.

If you prefer a refund, the cleanest way to build one is a fixed extra amount per paycheck in Step 4(c) of your W-4, such as $25 or $50. You'll know roughly how big the refund will be, and you can remove it at any time.

Owing taxes after changing jobs

Changing jobs mid-year creates the same problem as working two jobs at once. Each employer's payroll system withholds as if its salary, annualized, were your income for the whole year. If you earned $50,000 in the first half of the year at one job and $50,000 in the second half at another, each employer withheld as if you earned $100,000 for the full year at a $100,000 rate, which is usually close to right. But if you had a gap between jobs, or if one of them paid much more than the other, the totals can come out too high or too low.

Changing jobs can also mean excess Social Security withholding if your combined wages passed $184,500. That excess comes back as a credit on your return, which can offset a balance due elsewhere.

Retirees and people with pensions

Retirees often owe because pensions, IRA withdrawals and part of Social Security benefits are taxable but withholding on them is voluntary. Up to 85% of Social Security benefits can be taxable for retirees with other income above modest thresholds. If you didn't request withholding on Social Security (Form W-4V) or on pension and IRA distributions (Form W-4P or W-4R), you may owe at filing.

From 2025 through 2028, people 65 and older can claim an extra senior deduction of up to $6,000 each, which phases out above $75,000 of modified adjusted gross income ($150,000 joint). It lowers the tax owed, but it doesn't change withholding, so it typically shows up as a smaller balance due or a larger refund.

Check before you file

Our tax refund estimator compares the tax withheld so far with your estimated tax for the year, including the Child Tax Credit and the tips and overtime deductions, and shows whether you're heading for a refund or a balance due. Checking in October or November leaves enough paychecks to fix a gap through withholding.

Check your refund or balance due →