How to Lodge a BAS in Australia — Step-by-Step Guide

Updated

You can lodge your BAS online through the ATO Business Portal, through myGov (sole traders), via accounting software like Xero or MYOB, or through a registered BAS agent. Most businesses lodge quarterly, and the ATO provides a 28-day window after the end of each quarter to lodge and pay. Accounting software can pre-fill many fields from your transaction data, significantly reducing the time involved.

What You Need Before Lodging

Before you sit down to lodge your BAS, gather:

  • Total sales figures for the period (GST-inclusive)
  • Total purchases and business expenses (GST-inclusive)
  • A breakdown of any GST-free or input-taxed sales
  • Payroll records if you have employees (total wages, total PAYG withheld)
  • Your PAYG instalment income if you are in the instalment system
  • Your accounting software totals or spreadsheet summary

If you use accounting software, most of this data will be pre-populated once your transactions are categorised correctly.

Method 1 — Sole Traders via myGov

  1. Log in to my.gov.au and link your ATO account (one-time setup)
  2. Navigate to Tax → Activity Statements
  3. Select the relevant BAS period
  4. Enter figures in the relevant labels (G1, 1A, 1B, W1, W2 as applicable)
  5. Review the summary, confirm the net amount payable or refundable
  6. Submit — you will receive a confirmation reference number

Payment is made via BPAY, credit card, or direct debit from within the portal, or via EFT to the ATO’s bank account.

Method 2 — Businesses via ATO Business Portal

  1. Go to business.ato.gov.au and sign in with myID (formerly myGovID) with Standard or Strong identity strength
  2. Under Lodgements, select Activity Statements
  3. Open the relevant BAS and enter your figures
  4. Submit and follow through to payment if required

The Business Portal is available for all entity types — sole traders, companies, trusts, and partnerships.

Method 3 — Accounting Software (Xero, MYOB, QuickBooks)

Most accounting software packages integrate directly with the ATO and can lodge your BAS electronically:

In Xero:

  1. Ensure all transactions for the period are reconciled and coded correctly
  2. Go to Accounting → Reports → Tax → Activity Statement
  3. Review the auto-populated figures
  4. Click Prepare → Mark as Lodged (this generates the BAS data)
  5. Lodge directly from Xero using the Lodge with ATO button (requires connection setup)

In MYOB:

  1. Go to GST → Prepare BAS/IAS
  2. Review figures, make any adjustments
  3. Lodge via the built-in ATO lodgement connection

The key benefit of software lodgement is accuracy — the software pulls figures directly from your coded transactions, reducing manual entry errors.

Method 4 — Through a Registered BAS Agent

A BAS agent is licensed by the Tax Practitioners Board (TPB) to prepare and lodge BAS on your behalf. BAS agents also receive an extended lodgement deadline compared to self-lodgers.

BAS agents can:

  • Access the ATO’s Practitioner Lodgement Service (PLS) on your behalf
  • Lodge multiple clients’ BAS from their practice software
  • Obtain extended due dates (typically 28 days beyond the standard deadline for clients on a BAS agent’s lodgement program)

Find a registered BAS agent through the TPB register.

Paying Your BAS

After lodging, if you have a net GST amount owing (plus any PAYG withholding), payment is due on the same day as lodgement. Payment methods:

MethodDetail
BPAYUse the BAS payment reference number from the ATO
ATO Online (via portal)Direct debit or credit card
ATO Direct DebitSet up automatic payment for each BAS
In personAustralia Post (for amounts under $500,000)
Electronic Funds Transfer (EFT)ATO bank account — include your payment reference

If you cannot pay in full, contact the ATO on 13 11 42 to arrange a payment plan. Acting early reduces interest and penalties.

What Happens After You Lodge

  • You receive a lodgement confirmation via the portal or your software
  • The ATO processes your BAS and issues a statement of account
  • If you are owed a refund (your input tax credits exceed GST collected), the ATO will direct-deposit it to your nominated bank account — typically within 14 business days for online lodgements
  • If you underpay or pay late, the ATO may apply the Shortfall Interest Charge and Failure to Lodge penalties

Frequently Asked Questions

Can I lodge a BAS by paper? Yes, but paper lodgement is not recommended. Electronic lodgement is faster, more accurate, and often receives a faster refund turnaround. The ATO may still send paper BAS forms by mail to some registered businesses.

What if I miss the BAS lodgement deadline? The ATO applies a Failure to Lodge (FTL) penalty — currently one penalty unit ($330 as at FY2025–26) per 28-day period the BAS remains outstanding, up to a maximum of five periods ($1,650). Lodging late (even without paying) is better than not lodging at all, as the ATO will often remit penalties for first-time or isolated lateness.

Do I need a BAS agent or can I do it myself? Many sole traders and small business owners lodge their own BAS. If your GST reporting is straightforward — a single GST stream, no employees, simple purchases — self-lodgement is achievable. As your business grows in complexity (employees, FBT, mixed supplies, multiple entities), a BAS agent adds value.


This article provides general tax information. For advice tailored to your situation, speak with a registered tax agent or BAS agent. Find one through the Tax Practitioners Board register.