The tax deadline is here and you are not ready

The books are not finished, the deadline is days away, and the choice looks like filing something wrong or filing nothing.

It is neither. Extensions are routine, automatic when properly requested, and carry no penalty and no suspicion. Millions are filed every year. Your CPA files them constantly.

There is one thing about them that catches people, and it is expensive.

An extension to file is not an extension to pay

This is the whole of it, and it is the single most common misunderstanding in small business tax.

An extension gives you more time to submit the paperwork. It does not give you more time to pay what you owe. Tax is still due on the original deadline, and interest and a failure-to-pay penalty generally run from that date on anything unpaid — extension or not.

Which means the correct move when you extend is to estimate what you owe and pay it with the extension request, even though the return is not finished. Overpay slightly if you are unsure; the excess comes back.

The reason this matters so much: the penalty for failing to file is typically far larger than the penalty for failing to pay. So filing an extension and paying nothing still puts you in a much better position than not filing at all — and estimating and paying puts you in a better position again.

The mechanics

Different entity types file different forms and have different deadlines, and the dates shift when they fall on a weekend or holiday. Broadly:

• Partnerships and S corporations file earlier in the year than individuals, and extend using the business extension form.
• C corporations have their own deadline tied to their fiscal year end.
• Individuals, including sole proprietors and single-member LLCs reporting on a personal return, extend using the individual extension form.

If your business income lands on your personal return, note the trap: extending the business return does not extend the personal one, or the other way round. Both need doing where both apply.

States are separate. Some accept the federal extension automatically, some require their own, and some require a payment with it regardless. Check yours; this is a common and avoidable way to collect a state penalty while being properly extended federally.

What to do in the last week

1. Tell your CPA today that you are extending. They will handle it, and they would far rather know now than on the deadline.

2. Estimate the liability as well as you honestly can. Last year's tax is a reasonable starting point if the business is roughly the same size. If it grew, adjust upwards. Ask your CPA — they can usually give you a working figure quickly.

3. Pay the estimate. Electronically, dated before the deadline, so it is traceable.

4. Check the state.

5. Do not let it drift. The extension has an end date, and the whole benefit disappears if the same conversation happens again in the autumn with less runway.

What the extension is actually buying you

Time to get the books right, which produces a materially better return.

A rushed return filed on incomplete books misses deductions, because nobody found them, and it produces figures that get amended later. Amendments cost money, take months, and draw attention to a return that would otherwise have passed unremarked.

Filing well in the extension window beats filing badly on the original date, almost every time. The exception is if you are due a refund and need the cash — in which case getting it filed has its own logic.

The reason you needed one

Worth being honest about, because it is fixable.

Almost nobody needs an extension because their tax situation is complicated. They need one because eleven months of transactions were never categorised, nothing was reconciled, and the work that should have taken an hour a week is being attempted in a fortnight.

Contractors who move to monthly close mostly stop needing extensions after the first year. Not because the tax got simpler, but because in January there is nothing left to do — the year is already closed, and the CPA gets a finished set instead of a shoebox.

If you are reading this in a panic for the second year running, that is the thing to change, and the time to change it is now rather than next March.

Related

• Your CPA says the books are not ready to file
• What your CPA needs from you at year end
• Quarterly estimated taxes without the April surprise

This is general information about how filing extensions work, not tax advice. Deadlines, forms, penalty structures and state rules vary by entity type and change from year to year. Confirm the current dates and requirements with your CPA or enrolled agent.