You owe money because you did not pay enough tax during the year

When you file your tax return, you owe money because the total tax you paid through paychecks, estimated payments, or other sources fell short of what you actually owe. The IRS calculates what you should have paid based on your income, deductions, and credits for that year. If you paid less than that amount, the difference is what you owe.

This is not a penalty or a mistake on the IRS's part. It is simply how the tax system works: you pay as you earn throughout the year, and then you settle up when you file. Some people overpay and get a refund. Others underpay and owe a balance.

Key Takeaways

  • You owe money when your total tax for the year exceeds what you already paid through withholding or estimated payments.
  • Changes in income, deductions, filing status, or dependents during the year can create an unexpected balance owed.
  • If you cannot pay the full amount when you file, you can request a payment plan from the IRS, which spreads the cost over months.
  • The IRS charges interest and penalties on unpaid tax, so paying as soon as possible costs you less in the long run.

Common reasons your withholding was too low

If you have a job, your employer withholds tax from each paycheck based on a form called the W-4. If you filled it out incorrectly, claimed too many allowances, or did not update it after a major life change, you may have had too little withheld. The same applies if you have multiple jobs — withholding from one job does not account for income from another.

Self-employed people and freelancers do not have withholding at all. Instead, they are supposed to send estimated tax payments to the IRS four times a year. If you did not make these payments, or made them in amounts that were too small, you will owe when you file.

A sudden increase in income — from a raise, a bonus, investment gains, or a side business — can also push you into a higher tax bracket than your withholding was set up for. Your employer's system does not know about income from other sources, so it cannot adjust your withholding to account for it.

Changes that affect how much tax you owe

Your tax liability changes when your life circumstances change. If you got married, divorced, or had a child during the year, your filing status or number of dependents shifted, which changes your tax. If you bought a home and now have mortgage interest to deduct, or if you had large medical expenses, those deductions lower your tax — but only if you file and claim them.

Conversely, if you lost a deduction you had in previous years, or if you no longer may have access to for a credit you used to claim, your tax goes up. For example, if your income rose above the limit for the Earned Income Tax Credit, you lose that credit entirely, which can mean owing money even if your withholding stayed the same.

Some people owe because they withdrew money from a retirement account like a 401(k) or IRA. These withdrawals are treated as income, and if you did not have tax withheld from the withdrawal itself, you will owe tax on that money when you file.

How much interest and penalties will you pay

If you owe tax and do not pay by the deadline, the IRS charges interest on the unpaid amount. The interest rate changes quarterly and is currently in the range of 8 to 9 percent per year, though the exact rate depends on when you file and when you pay. Interest compounds daily, so the longer you wait, the more you owe.

The IRS also charges a failure-to-pay penalty if you do not pay the full amount by the tax deadline. This penalty is typically 0.5 percent of the unpaid tax per month, up to a maximum of 25 percent. If you file late, there is an additional failure-to-file penalty of 5 percent per month, which stacks on top of the failure-to-pay penalty.

If you cannot pay in full, it is better to file on time and pay what you can, then set up a payment plan, than to file late. Filing on time stops the failure-to-file penalty from growing, even if you still owe money.

Payment options if you cannot pay right away

The IRS offers several ways to pay if you do not have the full amount on hand. You can pay online through IRS.gov using a debit card, credit card, or electronic bank transfer. You can also pay by mail, phone, or in person at a local IRS office, though these methods take longer.

If you need more time, you can request a short-term extension to pay within 120 days, or a payment plan that spreads your debt over months or years. A payment plan requires a setup fee (usually $31 to $225 depending on the method) and you will still owe interest and penalties on the unpaid balance, but it lets you avoid a lump-sum payment you cannot afford.

To set up a payment plan, you can use the IRS Online Payment Agreement tool on IRS.gov, call the IRS at 1-800-829-1040, or include a request with your tax return. The IRS will tell you the monthly payment amount based on how much you owe and how long you want to take to pay it.

Adjusting your withholding for next year

If you owed money this year and do not want to owe again, you need to increase your withholding or estimated payments for next year. If you have a job, fill out a new W-4 and give it to your employer. The form asks about your income, dependents, and other jobs, and uses that information to calculate the right withholding amount.

If you are self-employed, calculate your expected income for next year and divide it by four to find your quarterly estimated tax payment. You can use IRS Form 1040-ES to do this calculation, or use the IRS tax withholding estimator on IRS.gov.

The key is to do this now, not next April. If you wait until you file next year's return, you will owe again. Changing your withholding or payments mid-year means you will have less to owe when you file next time.

Frequently Asked Questions

Can the IRS forgive or reduce what I owe?

The IRS can reduce penalties in some cases — for example, if you have a good payment history or if you have a reasonable cause for not paying on time. You can request penalty relief by calling 1-800-829-1040 or by filing Form 843 (Claim for Refund and Request for Abatement). Interest, however, is not forgiven; it accrues until you pay.

What happens if I ignore the bill and do not pay?

The IRS will send you notices and eventually place a tax lien on your property or issue a levy to seize money from your bank account or wages. A lien damages your credit and makes it hard to borrow money. A levy takes money directly without your permission. The longer you wait, the more aggressive the IRS becomes.

Do I have to pay the full amount by April 15?

You must file your return by April 15 (or the next business day if April 15 falls on a weekend). If you cannot pay in full by that date, file anyway and request a payment plan. Filing on time stops the failure-to-file penalty from growing, even though you will still owe interest on the unpaid balance.

Why did I owe this year when I got a refund last year?

Your tax situation changes year to year. A raise, a new job, a change in filing status, or loss of a deduction can flip you from owing a refund to owing a balance. Your withholding is based on the W-4 you filled out, which may not match your actual tax liability if your life has changed since you last updated it.

Can I use a credit card to pay the IRS?

Yes, but it costs extra. The IRS does not accept credit cards directly, but approved payment processors do. They charge a convenience fee of 1.87 to 2.35 percent of the amount you pay. You can find the list of approved processors on IRS.gov under payment options.