The IRS is the Internal Revenue Service, the federal agency that collects income taxes

IRS stands for Internal Revenue Service. It is the bureau of the U.S. Department of the Treasury responsible for collecting federal income taxes from individuals and businesses, and for enforcing the tax code. When you file a tax return or receive a tax refund, you are dealing with the IRS.

The IRS has existed since 1862, though it took its current name and structure in 1953. It operates regional offices across all 50 states and processes hundreds of millions of tax documents each year. Most people encounter the IRS once a year during tax season, but the agency also handles audits, payment plans, and disputes over tax liability.

Key Takeaways

  • IRS stands for Internal Revenue Service, a division of the U.S. Department of the Treasury that collects federal income taxes.
  • The IRS processes individual and business tax returns, issues refunds, and enforces federal tax law.
  • You can contact the IRS by phone, mail, or through its website at irs.gov to ask questions about your taxes or payment options.
  • The IRS also manages payment plans for people who owe taxes, handles appeals of tax decisions, and investigates tax fraud.
  • State income taxes are collected by your state's revenue department, not the IRS — the IRS handles only federal taxes.

What the IRS collects and enforces

The IRS collects federal income tax — the tax you owe to the federal government based on your wages, self-employment income, investments, and other sources. This is separate from state income tax, which most states collect through their own revenue departments. The IRS also collects federal payroll taxes (Social Security and Medicare taxes withheld from paychecks) and excise taxes on certain goods like fuel and alcohol.

Beyond collection, the IRS enforces the tax code by reviewing returns for accuracy, conducting audits when something looks wrong, and pursuing cases of intentional tax evasion. The agency also administers tax credits and deductions — programs like the Earned Income Tax Credit that reduce what you owe or increase your refund.

How the IRS processes your tax return

When you file a federal tax return, it goes to an IRS processing center in one of several locations across the country. The IRS scans your return, checks it for math errors and missing information, and matches it against documents the agency has already received — like W-2 forms from your employer or 1099 forms from banks and investment firms.

If everything matches and you are owed a refund, the IRS typically issues it within 21 days of accepting your return, though it can take longer if you claim certain credits or if the return requires manual review. If you owe taxes, the IRS will send you a bill. If you cannot pay in full, you can contact the IRS to set up a payment plan or request a temporary delay.

When the IRS audits a return

An audit is a formal review of your tax return to verify that the information is correct and that you paid the right amount. The IRS selects returns for audit based on statistical patterns, specific red flags (like unusually high deductions), or random selection. Most audits happen by mail — the IRS asks you to send documents that support the numbers on your return, such as receipts, bank statements, or invoices.

Some audits are conducted in person at an IRS office or your home or business. If you disagree with the IRS's findings after an audit, you have the right to appeal through the IRS Appeals Office, which is a separate division that reviews disputes between taxpayers and the agency.

How to contact the IRS

The IRS operates a phone line at 1-800-829-1040 for individual tax questions, available Monday through Friday during business hours. Wait times are often long during tax season (January through April). You can also visit irs.gov, the official IRS website, to read forms, read publications, check your refund status, or set up a payment plan online.

If you prefer to write, you can mail correspondence to the IRS address listed on your tax notice or on the IRS website. The IRS also offers in-person help at Taxpayer information Centers in many cities, though you may need to make an appointment. For complex tax situations, you can hire a tax professional — a CPA, enrolled agent, or tax attorney — to represent you before the IRS.

The difference between the IRS and state tax agencies

The IRS collects federal income tax only. Each state that has an income tax operates its own revenue or taxation department — for example, the California Franchise Tax Board or the New York Department of Taxation and Finance. You file separate returns to each: a federal return to the IRS and a state return to your state's agency.

Some states have no income tax at all (including Florida, Texas, and Wyoming), so residents of those states file only a federal return. If you move during the year or work in a state different from where you live, you may owe taxes to multiple states, and the rules for which state gets paid first can be complex. Your state's tax agency website will explain the rules for your situation.

Common reasons people contact the IRS

People reach out to the IRS to ask where their refund is, to report a change in income or filing status, to request a copy of a past tax return, or to discuss a notice they received. Others contact the IRS because they cannot pay their full tax bill and want to set up a payment plan or request an offer in compromise (a settlement for less than the full amount owed).

If you receive a notice from the IRS that you do not understand, do not ignore it — the notice will explain what the IRS found and what you need to do next. Many notices can be resolved by phone or mail without visiting an office. If the notice involves a large amount or a complex issue, consider consulting a tax professional before responding.

Frequently Asked Questions

Is the IRS the same as the Treasury Department?

No. The IRS is a bureau within the U.S. Department of the Treasury. The Treasury Department oversees federal finances, including the IRS, the U.S. Mint, and the Bureau of Engraving and Printing. When you pay federal income tax, that money goes to the Treasury, which then distributes it to federal agencies and programs.

Can the IRS take my bank account or wages if I owe taxes?

Yes, but only after following legal steps. The IRS can place a lien on your property, garnish your wages, or levy your bank account if you owe taxes and do not respond to notices or work out a payment plan. However, the IRS must send you notices and give you time to respond before taking these actions. If you owe, contact the IRS to discuss your options before enforcement begins.

What if I think the IRS made a mistake on my return?

You can dispute an IRS decision by filing a formal protest or requesting an appeals conference. The process depends on the amount in dispute and whether you have already been audited. The IRS will explain your appeal rights in any notice it sends you. You can also hire a tax professional to represent you in an appeal.

Do I have to file a tax return every year?

Not necessarily. You must file if your income exceeds a certain threshold, which changes each year based on your age and filing status. The IRS website has a tool to help you determine whether you are required to file. Even if you are not required to file, you may want to file anyway if you are owed a refund or if you claim tax credits.

What is the difference between a tax refund and a tax credit?

A tax credit reduces the amount of tax you owe, and some credits are refundable — meaning if the credit is larger than your tax bill, the IRS sends you the difference as a refund. A refund is money the IRS returns to you because you overpaid your taxes during the year (usually through withholding from your paycheck). Both result in money back, but they work differently.