Four calendars behind tax deadlines, compared side by side

What to take away

The four calendars, side by side

Most owners picture one tax deadline. A business with employees and customers runs four calendars at once, each on its own rhythm. Here are the four, side by side, with the forms each one actually produces.

The annual return is the famous one. The other three are the ones that generate penalties in the ordinary course of a year.

For a site about business tax, deductions, and mileage, these calendars matter because deductions and mileage claims ride on them. A mileage log is the record behind a business mileage deduction, and it has to be in place before the return is filed.

Expense records, receipts, and vehicle logs are gathered against the same dates that govern returns and estimated payments. Miss the date and a valid deduction can become a scramble, or disappear for lack of support. These four calendars tell you when your deduction and mileage records must be ready.

Calendar one: IRS Publication 509 and the annual return chain

Entity types do not file at the same time. A pass-through entity reports each owner's share before those owners can finish their own returns. The entity files first.

The link is the Schedule K-1, the statement each owner receives. A late entity return means late K-1s. Every owner waits, sometimes across several states.

A business taxed at the entity level runs on its own cycle. That cycle is keyed to its tax year end, not anyone's personal calendar.

Your deadline follows from how your business is taxed, not what it is called. An LLC has no 'LLC deadline'. If you are unsure which classification applies, settle that first, see entity tax treatment, because guessing means aiming at the wrong date.

Calendar two: IRS Publication 1518 and estimated payments

Nobody withholds for a sole proprietor. The system's answer is pay-as-you-go installments through the year. Three things about that catch people.

The obligation starts before you feel profitable, because it follows income, not your sense of the year. A strong year creates two bills at once: a balance for the year just ended and larger installments for the year underway. They often land weeks apart.

Underpaying through the year carries its own charge, separate from paying late at filing. Safe harbor rules exist to protect you if payments meet conditions tied to your income or prior year tax. Those conditions turn on your own numbers. Ask your preparer rather than adopting a rule someone repeated at you.

The habit that solves most of this: move a set percentage of every payment you receive into a separate account the day it lands. Pay installments from there. Ask your accountant what percentage fits. The number matters less than keeping the money out of your operating balance.

Calendar three: IRS Employment Tax Due Dates calendar

Payroll is the least forgiving calendar, because the withheld money was never yours. You hold it in trust.

Your deposit frequency is assigned to you based on the size of your payroll history. It is not a preference and it does not follow your cash flow. A slow month does not slow the deposit. See payroll tax for why that distinction drives everything else.

Worker statements sit on this calendar too. The W-2s and 1099-NECs your employees and contractors need to file their own returns are due to them early in the year, often before your books are closed.

Calendar four: state revenue department filing calendars

Each state assigns you a filing frequency and can change it as your volume changes. A return is generally required even for a period in which you collected nothing.

State annual reports are not tax filings, but they carry deadlines. Letting one lapse can put your entity's standing at risk. Every state you register in adds its own dates, and they do not line up with each other or with the federal ones. See sales tax for how registration and frequency interact.

An extension to file is not an extension to pay

This single misunderstanding causes more avoidable cost than anything else here.

An extension moves the date your paperwork is due. It does not move the date the money is due. Extend and pay nothing, and the tax was still owed on the original date, with interest and charges calculated from there.

Used correctly, an extension means estimate what you owe, pay that with the request, then take the extra time to get the return right. Filing an extension is routine, not a red flag.

If you cannot pay, file anyway, then ask your accountant about payment arrangements. Going silent is the one response that makes everything worse.

The deadlines that never make the list

Building your own calendar

Where to confirm the dates

The IRS's estimated taxes pages cover payments made through the year, not at the end. That is the half of the calendar people forget.

Start with its small business tax guide before accepting anyone's summary of the calendar, this page included. Note the year printed on it. Where a date moved for a weekend, a holiday, or a disaster postponement, only the current official source will tell you.

Common questions

What happens if I miss a deadline?

It depends which calendar. A late return, a late payment, and a late payroll deposit are treated differently and carry different consequences. Filing late generally costs more than paying late, so file on time even in a year you cannot pay in full. Call your accountant rather than waiting to see what arrives.

Does filing an extension increase my chances of being audited?

Extensions are ordinary and widely used. A carefully prepared return filed on extension beats a rushed one filed on time and amended later. The extension changes the filing date only, never the date the tax was due.

Do state deadlines match federal ones?

Sometimes, not always. Some states follow the federal calendar, some do not, and some have filings with no federal counterpart at all. Check each state where you have an obligation, separately, against that state's revenue department.

My business is new. When does anything start?

Sooner than most owners expect, and the specifics depend on when you started, how you are taxed, and whether you have employees. This is the best hour of professional advice you can buy in your first year, because almost everything else is downstream of it.