• 31 July, 2025

BAS Calculation Australia 2025: Simple Step-by-Step Guide for Businesses

Feeling stressed when your Business Activity Statement (BAS) is due? You’re not alone. Many Australian business owners find BAS confusing and worry about making costly mistakes.

The good news? BAS doesn’t have to be complicated.

This guide breaks down how to calculate BAS in Australia for 2025 in a simple, practical way—so you can lodge accurately, avoid penalties, and stay compliant with the ATO.

What Is a Business Activity Statement (BAS)?

A Business Activity Statement (BAS) is a report you submit to the Australian Taxation Office (ATO) to declare and pay your business taxes.

Think of it as your business’s tax summary, covering:

• Goods and Services Tax (GST)
• Pay As You Go (PAYG) withholding
• PAYG instalments (if applicable)

Why BAS Is Important

Lodging BAS correctly ensures:

• ✅ You stay compliant with ATO regulations
• ✅ You avoid penalties and interest charges
• ✅ You claim all eligible GST credits
• ✅ You maintain healthy cash flow

BAS Lodgement Rules for 2025–26

Your BAS frequency depends on your turnover:

• Quarterly → Most small businesses (under $20M turnover)
• Monthly → Businesses over $20M turnover
• Annually → Some small or voluntary GST businesses

GST Registration Threshold

• $75,000 (standard businesses)
• $150,000 (non-profits)

Key BAS Labels You Need to Know

When completing your BAS form, these are the most important fields:

G1 – Total Sales: All income including GST
1A – GST on Sales: GST collected
1B – GST on Purchases: GST credits
W1 – Gross Wages: Total employee payments
W2 – PAYG Withheld: Tax withheld from wages
T1/T11 – PAYG Instalments: Income tax prepayments

How to Calculate BAS (Step-by-Step)

Step 1: Calculate GST Collected (1A)

GST on sales = Total sales ÷ 11

Step 2: Calculate GST Paid (1B)

Add up GST included in business expenses

Step 3: Calculate Net GST

Net GST = 1A – 1B

• If positive → You pay ATO
• If negative → You get a refund

Step 4: Add PAYG Withholding

Total BAS payable = Net GST + PAYG withheld (W2)

Example BAS Calculation (2025)

BAS Label	Description	Amount (AUD)
G1	Total Sales	$33,000
1A	GST Collected	$3,000
1B	GST Paid	$1,200
W1	Wages	$18,000
W2	PAYG Withheld	$4,100

 

✅ Final Calculation

• Net GST = $3,000 – $1,200 = $1,800
• Total BAS Payable = $1,800 + $4,100 = $5,900

Real-World BAS Scenarios

Small Business Owner (Quarterly BAS)

A café owner tracks daily sales and expenses, making BAS easy at quarter-end.

Sole Trader Using Software

Using tools like Xero or MYOB:

• GST is automatically tracked
• Reports are generated instantly
• Errors are reduced

What Happens If You Get BAS Wrong?

❌ Underpayment or Overclaiming

• Interest charges apply
• Possible ATO penalties

❌ Late Lodgement

• Failure to Lodge (FTL) penalties
• Increased stress and compliance risk

Pro Tips for Accurate BAS Lodgement

✅ Use Accounting Software

Automates GST tracking and reduces manual errors

✅ Keep Proper Records

Maintain:

• Tax invoices
• Receipts
• Bank reconciliations

✅ Work With a BAS Agent

Experts ensure:

• Accurate reporting
• Maximum claims
• Full compliance

Common BAS Mistakes to Avoid

• ❌ Reporting incorrect GST at G1
• ❌ Claiming GST on exempt items
• ❌ Incorrect PAYG reporting
• ❌ Missing deadlines

Frequently Asked Questions

1. What is BAS in Australia?

A BAS is a report submitted to the ATO to declare GST, PAYG withholding, and other taxes.

2. How do I calculate GST for BAS?

Use the formula:
GST Payable = 1A – 1B

3. Can I fix a BAS mistake?

Yes. You can revise your BAS or correct it in your next lodgement.

4. How often do I lodge BAS?

Usually quarterly, but it depends on your turnover.

5. Should I do BAS myself or hire an expert?

You can do it yourself, but using a professional ensures accuracy and saves time.

Need Help With Your BAS?

BAS calculations can be confusing—but getting them wrong can be costly.

At Workpaper, we simplify BAS for you—ensuring accuracy, compliance, and peace of mind.

📞 Contact Us Today

Phone: 0485 825 915
Email: info@workpaper.com.au

Website: https://workpaper.com.au/

Address: 7 Bridge St, Werribee, VIC 3030