Tax deadlines and extensions: the dates that actually matter

Short answer: for most individuals it's April 15 to file and pay, and October 15 if you filed an extension — but an extension only extends the paperwork, never the money. Here are the dates that actually matter, and what happens when one slips by.

The dates worth marking on a calendar

• April 15 — individual returns are due, and any tax you owe is due with them. This is also the first quarterly estimated payment date.
• June 15 and September 15 — the second and third quarterly estimated payments.
• January 15 — the final estimated payment for the prior year.
• October 15 — the extended filing deadline for individual returns.
• March 15 — S-corporation and partnership returns are due (and their own extension deadline is September 15).

When a due date lands on a weekend or holiday, it shifts to the next business day — that's why the "same" deadline seems to move a little some years.

An extension is not a payment extension

This is the single most misunderstood rule in tax season. Filing an extension gives you more time to file your return — until October 15 for individuals. It gives you no extra time to pay. Whatever the IRS estimates you owe is still due on the original April date, and anything unpaid after that starts collecting interest and late-payment penalties, even if your extension was filed perfectly and on time.

If you can't pay in full by April, the strategy is still: file anyway, pay what you can, and set up a payment plan for the rest. The penalty for not filing is dramatically worse than the penalty for not paying in full — and the IRS offers installment agreements for the balance.

What happens if you miss a deadline

Two separate penalties can stack up, and they're both well-known IRS rules:

• Failure to file: generally 5% of the unpaid tax per month, capped at 25%. This is the expensive one — it's why filing, even late and even unpaid, beats not filing.
• Failure to pay: generally 0.5% of the unpaid tax per month, plus interest that accrues until the balance is paid.

Refunds don't disappear the same way. If you're owed a refund, there's no late-filing penalty — but you do have to claim it within the window the IRS allows, or it's gone for good.

Self-employed? Your calendar has more dates in it

If you're a 1099 worker with no withholding, quarterly estimated payments are how you stay penalty-free. Miss them and the penalty math applies per quarter — so a September miss isn't rescued by a big April payment.

Here's our approach: we don't nag you about your quarterly estimates. Once you're set up, our system sends scheduled reminders ahead of each due date and then gets out of the way — you're adults, and it's your business. The reminders are there when you want them, and we're a phone call away when a quarter turns out busier than you planned.

The bottom line

File on time, pay what you can on time, and let an extension buy you accuracy — not debt. And if a deadline just passed and you're staring at it, don't bury the letter in a drawer. Get an instant quote and let a human get you caught up — late returns are far more fixable than they feel.