If you earn self-employment income, freelance income, or side income without enough tax withholding, quarterly estimated taxes may apply sooner than you think. This quick guide explains who usually needs to pay, how self-employment tax fits in, and the key due dates to know.

Mailing a tax return or tax payment at the last minute may not protect you the way many taxpayers expect. This article explains how USPS postmark rules can affect tax deadlines, why the date you hand over your mail may not be the date that controls, and what steps can help you protect timely filing or payment.