BAS Due Dates 2025-26: Every Deadline Australian Businesses Need to Know

By Leah Moore | 3 February 2026

Every BAS due date for the 2025-26 financial year in one place - quarterly, monthly, and annual deadlines, BAS agent concession dates, and what happens if you lodge late. Bookmark this page and check back before each quarter closes.

The Australian Taxation Office sets different BAS lodgement and payment deadlines depending on whether you report monthly, quarterly, or annually. Missing these dates triggers automatic penalties and interest - and since 1 July 2025, that interest is no longer tax-deductible. Getting your dates right matters more than ever.

Quarterly BAS due dates 2025-26

Most Australian small and medium businesses with GST turnover under $20 million lodge BAS quarterly. The standard deadline is the 28th of the month following the end of each quarter. The one exception is Q2 (the December quarter), which already has a built-in one-month extension to 28 February because of the holiday period.

Important: The BAS agent concession dates only apply if your registered BAS agent has lodged your previous activity statement electronically and you are in good standing with the ATO. If your agent is lodging your first-ever activity statement, or your previous BAS was lodged on paper, you may need to meet the earlier standard deadline. Check with your agent to confirm which date applies to you.

If a due date falls on a weekend or public holiday, the deadline automatically extends to the next business day.

Monthly BAS due dates 2025-26

Businesses with GST turnover of $20 million or more must report monthly. Some smaller businesses also elect to report monthly - usually because they are regularly in a GST credit position and want faster refunds.

Monthly BAS is due on the 21st of the following month, every month. There is no agent concession for monthly BAS - with one exception.

The December monthly BAS is the only month where registered BAS agents get a concession - an extra month, pushing the deadline from 21 January to 21 February. This concession only applies to businesses with turnover up to $10 million who lodge electronically through a registered agent.

Annual BAS

Businesses that are voluntarily registered for GST with annual turnover under $75,000 ($150,000 for not-for-profits) can elect to report and pay GST annually. The due date is 31 October 2026 for the 2025-26 year, or 28 February 2027 if you do not have a tax return lodgement obligation.

Annual reporting suits very small businesses with straightforward GST positions. If your business is growing, quarterly reporting gives you better visibility of your GST position throughout the year and avoids a large end-of-year payment.

What goes on your BAS

Your BAS covers more than just GST. Depending on your business, it can include several different tax obligations reported on a single form:

Goods and Services Tax (GST) - the difference between GST collected on sales and GST paid on purchases. This is the core obligation for most businesses.

PAYG withholding - the tax you withhold from employee wages and contractor payments. Small withholders (withholding under $25,000 per year) report this quarterly on their BAS. Medium withholders ($25,000 to $1 million) report monthly.

PAYG instalments - prepayments towards your own income tax liability, calculated based on your prior year tax assessment. The ATO sets either a fixed instalment amount or a rate you apply to your current income.

Fuel tax credits - if your business uses fuel in machinery, heavy vehicles, or certain other applications, you claim credits through your BAS.

Fringe Benefits Tax (FBT) instalments - quarterly FBT instalments for businesses that provide fringe benefits to employees.

Wine equalisation tax and luxury car tax - reported on BAS by businesses in those sectors.

Getting any of these wrong affects more than just your BAS - it flows through to your annual tax position. This is why accurate bookkeeping throughout the quarter matters far more than a last-minute scramble before the deadline.

What happens if you lodge late

The ATO has two separate penalties for late BAS: a failure to lodge penalty and interest on any unpaid amount. Both apply independently - you can be hit with both at the same time.

Failure to lodge (FTL) penalty

If you miss the BAS deadline, the ATO can impose a failure to lodge penalty. The penalty is calculated in penalty units - one unit for every 28-day period (or part thereof) that the BAS is overdue, up to a maximum of five penalty units.

From 1 July 2025, one penalty unit is worth $330. The maximum depends on your business size:

These penalties apply per late lodgement. If you are late on two quarters, you face two separate penalties. A small business that misses all four quarterly BAS lodgements in a year could face $6,600 in penalties - even if the BAS results in a nil or refund outcome.

The ATO generally warns you before applying FTL penalties and gives you a chance to lodge. But if you have a pattern of late lodgement, they are increasingly likely to apply penalties automatically.

General Interest Charge (GIC)

If you owe money on your BAS and do not pay by the due date, the ATO charges General Interest Charge on the unpaid amount. GIC is calculated daily on a compounding basis.

The GIC rate for January-March 2026 is 10.65% per annum. The rate is updated quarterly and is tied to the Reserve Bank 90-day bank bill rate plus a 7% uplift.

Critical change from 1 July 2025: GIC is no longer tax-deductible. Previously, businesses could claim a deduction for GIC paid, which reduced the after-tax cost by 25-30%. Under the new rules, the full amount comes out of after-tax dollars. A $10,000 GIC bill now costs $10,000 - not the $7,000 it effectively cost before. This makes paying your BAS on time significantly more important than it was even 12 months ago.

How to stay on top of BAS deadlines

The businesses that never stress about BAS deadlines have one thing in common: their bookkeeping is current throughout the quarter, not just at the end of it. Here is what that looks like in practice.

Reconcile weekly, not quarterly. If you are using Xero, bank feeds update automatically. Set aside 30 minutes each week to code transactions and reconcile. When the quarter ends, your BAS preparation is a review exercise - not a data entry marathon.

Separate your GST and PAYG withholding funds. Open a dedicated savings account and transfer your estimated GST and PAYG amounts after each pay run or invoicing cycle. When the BAS payment is due, the money is already set aside. This eliminates the cashflow shock of a large quarterly payment.

Use Xero Activity Statements. Xero generates your BAS directly from your coded transactions. If your bookkeeping is current, Xero can prepare a draft BAS in minutes. Your BAS agent can then review, adjust, and lodge electronically - which also qualifies you for the agent concession deadlines.

Lodge early when you are in a refund position. If your business regularly pays more GST on purchases than it collects on sales, you are in a net refund position. Lodge your BAS as early as possible after the quarter ends to get that money back into your business faster. There is no benefit to waiting until the deadline when the ATO owes you money.

Set calendar reminders four weeks before each deadline. The reminder is not for lodging - it is for your bookkeeper or BAS agent to start preparing. Giving your agent four weeks means they can review your records, raise any queries, and lodge with time to spare. Last-minute lodgements are where errors happen.

When to use a registered BAS agent

A registered BAS agent does more than give you extra time to lodge. They take responsibility for the accuracy and compliance of your BAS - and if your agent makes an error, the ATO safe harbour provisions can protect you from penalties.

Using a BAS agent makes particular sense if your business has employees (PAYG withholding adds complexity), if you claim fuel tax credits, if you have a mix of GST-free and taxable supplies, or if you simply do not want to think about BAS compliance at all.

At Digit, BAS preparation and lodgement is part of our core bookkeeping service. Your books are maintained continuously through the quarter, so when the deadline approaches, your BAS is already prepared. No last-minute scrambles, no late lodgements, no penalties.

Key dates calendar: 2025-26 at a glance

Pin this to your wall or save it to your phone. Every BAS-related deadline for the financial year in one list:

Monthly BAS lodgers: your deadline is the 21st of the following month, every month. No exceptions except the December concession noted above.

Sources

All dates and penalty information in this article are sourced from the Australian Taxation Office:

BAS agent lodgment program 2025-26 - ATO

Due dates for lodging and paying your BAS - ATO

Failure to lodge on time penalty - ATO

General interest charge (GIC) rates - ATO

This article was last updated on 15 February 2026. BAS due dates and penalty rates are reviewed by the ATO periodically. We update this page each financial year - but always confirm dates with the ATO or your registered BAS agent before lodging.