BAS due dates for 2026⁠–⁠27: quarterly, monthly and agent dates

If you're registered for GST or pay PAYG instalments, knowing your BAS due dates helps you avoid penalties, interest and last-minute scrambles. This guide sets out the quarterly and monthly BAS due dates for 2026⁠–⁠27, the extra time that may be available when a registered agent lodges for you, and what to do if you can't lodge or pay on time.

BAS due dates for 2026⁠–⁠27 at a glance

Most small businesses lodge a business activity statement (BAS) quarterly. Each due date is the date to both lodge and pay.

A few things to note:

• Quarter 2 already has extra time built in, so its due date is the same however you lodge.
• 28 February 2027 falls on a Sunday, so the weekend rule applies (more on that below).
• The agent dates only apply when the conditions of the ATO's lodgment program are met.

What your BAS covers

Depending on your registrations, a BAS can report several obligations in one form:

• GST collected on your sales and GST credits on your business purchases
• PAYG withholding from wages you pay to employees
• PAYG instalments towards your income tax for the year
• other amounts for some businesses, such as fuel tax credits

Because they share one due date, a late or unpaid BAS affects all of them at once, not just GST.

Quarterly or monthly: which applies to you?

Your GST reporting cycle depends mainly on your GST turnover:

• Monthly if your GST turnover is $20 million or more.
• Quarterly if your GST turnover is under $20 million, unless the ATO has told you to report monthly.
• Annually may be an option if you're registered for GST voluntarily and your GST turnover is under $75,000.

If you're not sure which cycle you're on, your activity statements in ATO online services will show the period and due date for each one.

Monthly BAS due dates

A monthly BAS is due on the 21st day of the month after the period ends. For example, the August 2026 statement is due on 21 September 2026, and the September 2026 statement is due on 21 October 2026.

December is the exception. Under the ATO's lodgment program, the December monthly BAS is generally due on 21 February rather than 21 January for businesses with turnover up to $10 million that report GST monthly and lodge electronically. Businesses using deferred GST aren't eligible for the later date.

Several monthly due dates in 2026⁠–⁠27 land on a weekend, including 21 November 2026 (a Saturday) and 21 February 2027 and 21 March 2027 (both Sundays). In each case you can lodge and pay on the next business day.

How a registered agent can give you more time

When a registered tax or BAS agent lodges your quarterly BAS electronically, the ATO's lodgment program generally allows about four extra weeks for quarters 1, 3 and 4. The later date applies to payment as well as lodgment.

The extra time isn't automatic for every statement. Generally:

• your previous activity statement must have been lodged electronically
• a first activity statement may need to be lodged by an earlier date
• some instalment notices keep the standard due date
• quarter 2 gets no further extension

Example (illustrative only): if your agent lodges your quarter 3 BAS electronically and the conditions are met, you'd have until 26 May 2027 to lodge and pay, rather than 28 April 2027. That's four more weeks of cash flow, but the records still need to reach your agent in good time.

If you lodge online yourself, you may be eligible for the ATO's two-week lodgment concession for quarters 1, 3 and 4. You don't need to apply. If you qualify, the due date on your statement updates automatically.

If your business is a company, trust or partnership, you'll need to nominate a new agent in Online services for business before they can act for you. Sole traders are excluded from this step.

What if a due date falls on a weekend or public holiday?

If a due date falls on a Saturday, Sunday or public holiday, you can lodge and pay on the next business day without a penalty or interest. For this rule, a public holiday is a day that's a public holiday for the whole of any state or territory. It then applies to everyone, even if it isn't a holiday where you live.

The big one this year is quarter 2. Because 28 February 2027 is a Sunday, you can lodge and pay on the next business day. Check the due date shown in ATO online services, and allow time for your payment to reach the ATO.

Late lodgment: penalties and interest

Failure-to-lodge penalty

The ATO can apply a failure-to-lodge penalty of one penalty unit for each 28 days (or part of 28 days) that a statement is late, up to a maximum of five units.

• For failures on or after 1 July 2026, one penalty unit is $364. From 7 November 2024 to 30 June 2026 it was $330.
• For a small business, the maximum is five units, which is $1,820.
• The penalty is doubled for medium entities and multiplied by five for large entities (broadly, assessable income or GST turnover of more than $1 million, and $20 million or more, respectively).

Generally, the ATO won't issue this penalty for a late statement that results in a refund or a nil amount, although there are exceptions. You can also ask the ATO to remit a penalty, explaining why the statement was late.

Example (illustrative only): a small business lodges its quarter 1 BAS 60 days late. That covers three 28-day periods (the third one partly), so the penalty could be three units, or $1,092.

General interest charge

The general interest charge (GIC) applies to amounts that aren't paid by the due date. It's calculated daily on a compounding basis until the debt is paid. The rate is updated each quarter. For July to September 2026, the annual rate was 11.43%.

GIC and shortfall interest charge incurred on or after 1 July 2025 are no longer tax deductible, even if the underlying debt relates to an earlier year. That makes an unpaid BAS more expensive than it used to be.

Example (illustrative only): $10,000 left unpaid for 30 days at the July to September 2026 rate would attract about $94 in GIC. Left for 90 days at the same rate, it would be about $286, and none of it is deductible.

Can't pay on time? Your options

The most important step is to lodge on time anyway. Lodging avoids the failure-to-lodge penalty, even if you can't pay the full amount yet.

Then:

• Talk to the ATO or your agent before the due date. Early contact gives you more options.
• Consider a payment plan. If you owe $200,000 or less, you may be able to set one up through ATO online services. GIC keeps accruing, so a shorter plan costs less. Income tax and activity statement debts need separate plans.
• Ask about interest relief. In some cases, small businesses with a good payment and lodgment history may qualify for an interest-free plan on recent activity statement debts.
• Don't ignore reminders. Unpaid debts can lead to firmer action. Our guide on what to do when you get a letter from the ATO explains the common letters and how to respond.

Practical tips for staying ahead of your BAS

• Put GST and PAYG withholding aside as you go. A separate bank account stops tax money being spent on day-to-day costs.
• Reconcile monthly, even if you lodge quarterly. Small errors are easier to fix when they're fresh.
• Diarise every date, including the ones shifted by weekends.
• Treat the agent date as a lodgment date, not a bookkeeping date. Send your records early so there's time to check them properly.
• Lodge nil statements on time. If you had no activity, you still need to lodge.
• Remember super is now separate. From 1 July 2026, under Payday Super, employers must pay super guarantee each payday, and it must reach the employee's fund within 7 business days. It's no longer a quarterly task that lines up with your BAS.
• Keep your records for five years, and keep your claims tidy. Our guide to small business tax deductions covers what you may be able to claim.

How Jan can help

Jan prepares and lodges BAS for sole traders and small businesses on the Northern Beaches and online across Australia, using the agent lodgment program where it applies. You deal with Jan directly, with a fixed-fee quote before any work starts. See BAS, GST and PAYG services or book a free intro call to get your 2026⁠–⁠27 dates under control.