BAS Deadlines 2026: Every Date Sole Traders and Small Businesses Need

Miss a BAS deadline and the ATO starts charging penalties from day one. No warning letter, no grace period. The fine is $313 for every 28 days your BAS is overdue, stacking up to a maximum of $1,565.

Here are all the dates you need for the 2026 financial year and beyond, whether you lodge quarterly, monthly, or annually.

Quarterly BAS Deadlines (2025-26 and 2026-27)

Most small businesses lodge quarterly. Your BAS covers a three-month period, and you have roughly four weeks after the quarter ends to lodge and pay.

Monthly BAS Deadlines

If your GST turnover is $20 million or more, or you've chosen to report monthly, your BAS is due on the 21st of the following month.

Annual BAS Deadlines

Annual lodgers report GST once a year. Your BAS for the full financial year (1 July 2025 to 30 June 2026) is due by 28 February 2027.

If you only report GST annually (no PAYG), the same date applies: 28 February 2027.

What Happens When a Deadline Falls on a Weekend or Public Holiday

The ATO shifts the deadline to the next business day. If 28 October falls on a Saturday, your BAS is due on Monday 30 October instead.

This rule applies to all lodgement types: quarterly, monthly, and annual. Check the ATO's website or your myGov account to confirm adjusted dates, because state public holidays (like Melbourne Cup Day in Victoria) can also push deadlines.

Tax Agent Extensions

Using a registered tax agent or BAS agent? You typically get an extra four weeks on top of the standard deadline. Your agent manages this automatically through their lodgement program with the ATO.

The extension only applies if you were registered with your agent before the original due date. You can't appoint an agent on 27 July and expect an extension for the Q3 BAS due on 28 July.

Penalties for Late Lodgement

The ATO applies a Failure to Lodge (FTL) penalty if your BAS is overdue. The penalty is calculated in "penalty units," which the government adjusts each year.

• 1 to 28 days late: 1 penalty unit ($313)
• 29 to 56 days late: 2 penalty units ($626)
• 57 to 84 days late: 3 penalty units ($939)
• 85 to 112 days late: 4 penalty units ($1,252)
• 113+ days late: 5 penalty units ($1,565) - maximum

These amounts apply per BAS. If you're behind on three quarters, the ATO can penalise each one separately. That's up to $4,695 for three overdue statements.

Small entities (turnover under $1 million) may have the penalty reduced by the ATO on a case-by-case basis. If you've got a clean history and a genuine reason, call them on 13 28 66 before the penalty notice arrives.

How to Set Up Reminders

The ATO can send you reminders through your myGov inbox, but these arrive only a few days before the deadline. Set your own reminders at least two weeks out.

• Phone calendar: Add recurring reminders for the 14th and 7th day before each deadline
• Accounting software: Xero, MYOB, and QuickBooks all have built-in BAS reminders. Turn them on in settings.
• ATO app: The ATO app shows your next lodgement date on the home screen. Free on iOS and Android.
• mybas.ai: Use the free BAS tool on this site to check your next deadline instantly

Quick Reference

• Quarterly lodgers: due 28th of the month after the quarter ends
• Monthly lodgers: due 21st of the following month
• Annual lodgers: due 28 February
• Weekend/holiday: rolls to next business day
• Tax agent: typically 4 extra weeks for lodgement
• Late penalty: $313 per 28 days, up to $1,565 per BAS

Put the dates in your calendar now. Future you will be grateful.