Federal taxes are the largest source of government revenue — and also one of the most common targets for scams.

Individual income taxes, payroll taxes, corporate taxes, excise taxes, and customs duties fund nearly every federal responsibility, from defense to courts to benefits. Tax information changes often enough that a third-party summary should never replace the IRS’s own current instructions.

The IRS generally sends important notices by mail, not by phone, text, or email.

Guide to Government

Largest revenue sourceIndividual income taxes
Official sourceIRS.gov
IRS notices arrive byMail
Guaranteed refunds promised?A scam warning sign

Common Practical Needs

Worth knowing

Real IRS communication has a predictable pattern — scams try to break it

A common misconception is that any call, text, or email claiming to be from the IRS deserves an immediate, urgent response. The IRS generally initiates contact by mail, not by phone call, text message, or email demanding immediate payment. Be especially cautious of anyone promising a guaranteed refund amount, threatening immediate arrest, demanding payment via gift cards, or asking for passwords and verification codes — these are consistent, well-documented scam patterns, not how the actual IRS operates.

How Taxes Connect to Federal Spending

The largest single revenue source

Taxes fund nearly everything else on this site

Individual income taxes, payroll taxes, corporate income taxes, excise taxes, and customs duties together fund federal programs, agencies, benefits, interest on debt, national defense, courts, and public health — nearly every topic covered elsewhere in this Guide to Government traces back to this revenue in some way.