Adelaide | Registered BAS Agents for Small Business
Adelaide’s registered BAS agents preparing and lodging your Business Activity Statement on time, every quarter. GST, PAYG withholding, PAYG instalments, and FBT handled accurately, so you never miss a deadline or overpay the ATO.
Your BAS, Lodged Correctly, Without the Last-Minute Scramble.
A Business Activity Statement is not something you want to get wrong. Incorrect GST reporting triggers ATO amendments and potentially a General Interest Charge that now compounds daily at approximately 10.96% per annum. Late lodgement attracts failure-to-lodge penalties starting at $330 per 28-day period from 1 July 2025. And unlike previous years, the interest is no longer tax-deductible.
At The Kalculators, our registered BAS agents reconcile your accounts throughout the quarter, ensuring your BAS is accurate when the due date arrives. We lodge directly with the ATO on your behalf, and because we are registered agents, you get access to extended lodgement deadlines that are not available if you lodge yourself. Combined with our small business bookkeeping, your financial records stay up to date year-round, not just at BAS time.
Our BAS Lodgement Services in Adelaide
We handle every aspect of BAS preparation and lodgement for Adelaide small businesses, sole traders, and GST-registered entities.
BAS Preparation & Lodgement
Complete quarterly or monthly BAS preparation, including GST calculations, PAYG withholding reconciliation, PAYG instalment review, and electronic lodgement with the ATO. We reconcile your bookkeeping records and ensure every figure is substantiated before lodgement.
GST Registration & Reporting
If your business turnover reaches $75,000 ($150,000 for non-profits), you must register for GST within 21 days. We handle registration, set up your accounting software for correct GST tracking, and ensure every BAS accurately reports GST collected and paid.
PAYG Withholding Management
If you have employees, your BAS must report the tax withheld from their wages. We reconcile PAYG withholding amounts against your payroll records and Single Touch Payroll (STP) data to ensure accuracy.
PAYG Instalment Review
PAYG instalments are pre-payments of your expected income tax. If your business income has changed significantly, we vary your instalment amount to prevent overpaying or facing a large end-of-year shortfall.
BAS Error Correction & Amendment
If you have lodged an incorrect BAS in a previous period, we will prepare and lodge a revision. The ATO allows BAS amendments, and correcting errors proactively is significantly better than waiting for an ATO review.
Fuel Tax Credits & Industry-Specific Reporting
Businesses in transport, agriculture, construction, and mining may be eligible for fuel tax credits on their BAS. We calculate your entitlement and include it in your lodgement.
Don’t Just Take Our Word For It
Ghulam. G
Adelaide, Australia
Satisfied with the services they are providing. Friendly staff. Bilal did my taxes at prospect office and I highly recommend them for your taxes.
BAS Due Dates for 2025-26
The ATO sets different BAS deadlines depending on your reporting frequency. For full details, see the ATO’s Business Activity Statements page.
Quarterly BAS Due Dates
| Quarter | Period Covered | Self-Lodge Due | BAS Agent Due |
|---|---|---|---|
| Q1 | 1 Jul - 30 Sep 2025 | 28 October 2025 | 25 November 2025 |
| Q2 | 1 Oct - 31 Dec 2025 | 28 February 2026 | 28 February 2026 |
| Q3 | 1 Jan - 31 Mar 2026 | 28 April 2026 | 26 May 2026 |
| Q4 | 1 Apr - 30 Jun 2026 | 28 July 2026 | 25 August 2026 |
Using a registered BAS agent like The Kalculators gives you up to 4 additional weeks on most quarters. The one exception is Q2 (December quarter), where both self-lodge and agent deadlines are 28 February.
Monthly BAS Due Dates
Monthly BAS is due on the 21st of the following month. Businesses with GST turnover of $20 million or more are required to lodge monthly.
Annual BAS
Businesses with turnover under $75,000 that have voluntarily registered for GST can lodge annually.
Annual BAS for the 2025-26 year is due by 31 October 2026, or with your income tax return if lodged through a tax agent.
What Happens If You Lodge Your BAS Late
The ATO imposes two separate penalties for late BAS:
- Failure to Lodge (FTL) Penalty: $330 per 28-day period (or part thereof) that the BAS is overdue, up to a maximum of 5 penalty units ($1,650) per late BAS for small businesses. These penalties apply per late lodgement, so missing all four quarterly BAS in a year could cost $6,600 in penalties alone.
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- General Interest Charge (GIC): If you owe money on your BAS and do not pay by the due date, the ATO charges GIC at approximately 10.96% per annum, compounding daily. From 1 July 2025, GIC is no longer tax-deductible. See our guide on how to pay the ATO for payment options and plans.
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What Your Business Activity Statement Includes
Your BAS is more than a tax form; it is a complete snapshot of your business's tax obligations in a single quarterly lodgement. Understanding each label ensures nothing is missed, and no credits are left unclaimed.
| BAS Label | What It Reports | Who It Applies To |
|---|---|---|
| 1A - GST on sales | GST collected on your taxable sales | All GST-registered businesses |
| 1B - GST on purchases | GST credits on eligible business purchases | All GST-registered businesses |
| W1-W5 - PAYG withholding | Tax withheld from employee wages | Businesses with employees |
| T1-T4 - PAYG instalments | Pre-payments of your expected income tax | Businesses notified by ATO |
| 7A-7D - Fuel tax credits | Credits for fuel used in business vehicles/machinery | Transport, agriculture, mining, and construction |
| F1-F4 - FBT instalment | Fringe benefits tax instalment | Businesses providing fringe benefits |
South Australia’s Fastest Growing BAS & Accounting Firm
Founded by Kaleem Ullah, The Kalculators was built to make professional accounting and BAS services accessible to every South Australian business. Over 10+ years, we have grown to serve 20,000+ clients annually from three offices in Salisbury, Blair Athol, and Morphett Vale, with online BAS services reaching Murray Bridge, Woodville, Melrose Park, Port Augusta, Prospect, and Brighton.
IPA Practice of the Year
(SA & NT – 2025)
Xero Gold Partner
AusMumpreneur Awards
– Business Excellence
Member of the Year 2019 –
Institute of Public Accountants
Member of the Year 2025 –
Institute of Public Accountants
Tax Practitioners Board
Registered Agent
Australian Accounting
Awards (2019)
Australian Accounting
Awards (2020)
Australian Accounting
Awards (2021)
0k+
Returns Annually0+
Tax Consultants$0M+
In Claimed Deductions0+
Office LocationsWhy Adelaide Businesses Choose The Kalculators for BAS Lodgement
- Registered BAS agents with extended lodgement deadlines (up to 4 extra weeks on most quarters)
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- 10+ years preparing and lodging BAS for Adelaide sole traders, partnerships, companies, and trusts
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- Xero Gold Partner with expertise in MYOB and QuickBooks
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- Three Adelaide offices (Salisbury, Blair Athol, Morphett Vale) plus online services across Murray Bridge, Woodville, Melrose Park, Port Augusta, Prospect, and Brighton
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- Integrated with our small business tax return, bookkeeping, and business advisory services so your BAS, tax return, and financial strategy are always aligned
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- Multilingual, multicultural team serving Adelaide’s diverse business community
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- IPA Practice of the Year SA & NT 2025 | IPA Member of the Year SA/NT 2019 & 2025
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BAS Lodgement for Every Type of Adelaide Business
We prepare and lodge BAS for businesses at every stage, from newly GST-registered sole traders to established companies with complex reporting obligations.
Sole Traders & Freelancers
Quarterly BAS covering GST on sales and purchases. If your turnover is under $75,000, we advise whether voluntary GST registration benefits your business. See our sole trader tax return page for more.
Small Businesses with Employees
Quarterly BAS with PAYG withholding from employee wages, plus super guarantee compliance. From 1 July 2026, Payday Super means super must be paid on every pay run, adding a new layer of complexity to payroll and BAS reconciliation.
Property Investors
If your investment property is held in a GST-registered entity (such as commercial property in a trust), your BAS must correctly report GST on rent collected and input tax credits on property expenses.
E-Commerce & Online Businesses
GST on digital sales, marketplace facilitator rules, and international transaction reporting. See our eCommerce accountant page for industry-specific advice.
Trusted by Thousands Across South Australia
Our Branch Locations
Salisbury Branch
salisbury@thekalculators.com.au
182 Salisbury Highway, Salisbury, SA 5108
Frequently Asked Questions
Ready to Get Your BAS Lodged On Time? Talk to a Registered BAS Agent Today.
Whether you are a sole trader lodging your first quarterly BAS or a growing business with employees and complex PAYG obligations, our BAS lodgement service keeps you compliant and penalty-free. Accurate preparation, on-time lodgement, and extended deadlines through a registered BAS agent.
With three offices across Adelaide (Salisbury, Blair Athol, Morphett Vale) and online services reaching Murray Bridge, Woodville, Melrose Park, Port Augusta, Prospect, and Brighton, professional BAS services have never been more accessible in South Australia.
Contact our team today for a no-obligation consultation.
