When are taxes due?

April 15 for federal returns, or the next business day when the 15th falls on a weekend or a DC holiday. Most states match the federal date, though a few run their own calendar.

You can file for an automatic six-month extension to October 15, and here is the part people get wrong: the extension covers the paperwork, not the money. If you owe, payment is still due in April, and interest plus penalties run from April 15 on any unpaid balance.

If you cannot pay in full, file anyway. The failure-to-file penalty is roughly ten times the failure-to-pay penalty, and the IRS offers payment plans online in minutes.

Two other deadlines catch people out. Quarterly estimated tax payments, which apply to freelancers, contractors, and anyone with substantial income not subject to withholding, fall in mid-April, mid-June, mid-September, and mid-January of the following year, and missing them triggers an underpayment penalty even if you settle up fully in April. And the deadline for contributing to an IRA or health savings account for the prior tax year is the April filing date rather than December 31, which is a genuinely useful window for anyone who realizes in March that they want to reduce last year's taxable income.

A few situations shift the date. Taxpayers living abroad get an automatic two-month extension to mid-June. Members of the armed forces in combat zones get additional time. And the IRS routinely postpones deadlines for entire regions following federally declared disasters, sometimes by months, which is announced on its newsroom page rather than mailed to you. Business returns run on their own calendar, with partnership and S-corporation returns generally due a month earlier than individual returns, which surprises new business owners in their first filing year.