BAS Calculator

Calculate your Business Activity Statement amounts including GST collected, GST paid, and PAYG instalments.

Data stays on your deviceATO sourced data

Calculate your Business Activity Statement (BAS) amounts. Use the GST calculator below to work out your GST collected and GST paid for the reporting period.

BAS is lodged quarterly (or monthly for businesses with turnover >$20M)
Report GST collected on sales minus GST paid on purchases
PAYG instalments may also be reported on your BAS
Lodge online via myGov or through your tax agent

BAS Period

Method

Sales / Income

Total Sales (incl. GST)

G1 — All sales where you charged GST

GST-Free Sales

G3 — Exports, food, medical, education, etc.

Purchases / Expenses

Purchases (incl. GST)

G11 — All purchases where GST was charged to you

Purchases (no GST)

Wages, bank fees, insurance — no GST credits

PAYG (optional)

PAYG Instalment (T7)

Your own income tax instalment

PAYG Withheld (W1)

Tax withheld from employee wages

BAS Amount Owing

$2,727.27

Quarterly BAS — cash basis

GST

1A — GST on sales$4,545.45

1B — GST on purchases$1,818.18

Net GST (payable)$2,727.27

Total sales (G1)$50,000.00

Total purchases (G11)$25,000.00

GST collected$4,545.45

GST credits claimed$1,818.18

Total payable$2,727.27

This is an estimate to help you prepare your BAS. The actual BAS must be lodged through the ATO Business Portal, myGov, or your registered tax agent. Ensure your bookkeeping is up to date before lodging. BAS is due 28 days after the end of the quarter (or 28 February for the December quarter).

Disclaimer

This calculator provides estimates for general information purposes only. Results should not be relied upon as professional financial, tax, or legal advice. Tax rates and thresholds are based on publicly available ATO data and may change. Always consult a qualified tax agent or financial adviser for advice specific to your circumstances.

Frequently Asked Questions

How often do I need to lodge a BAS?

Most small businesses lodge BAS quarterly. Businesses with annual turnover over $20 million must lodge monthly. Businesses with turnover under $10 million may opt to report GST annually. Your BAS cycle is assigned by the ATO when you register for GST.

What happens if I lodge my BAS late?

Late lodgement attracts a Failure to Lodge (FTL) penalty of $313 for each 28-day period the BAS is overdue, up to a maximum of 5 periods ($1,565). Late payment of the BAS amount also incurs interest (General Interest Charge) at approximately 11% per annum.

What is BAS?

A Business Activity Statement (BAS) is a form submitted to the ATO that reports your business's GST, PAYG withholding, PAYG instalments, and other tax obligations. Most businesses lodge quarterly.

How this calculator works

Use the GST calculator to work out your BAS figures. The key BAS fields are: 1A (GST on sales — the total GST you've collected from customers), 1B (GST on purchases — the GST you've paid on business expenses), and the difference is what you owe or are owed. BAS is due quarterly: 28 October, 28 February, 28 April, and 28 July. Late lodgement attracts penalties starting at $313 per 28-day period. Small businesses with turnover under $10 million can report GST annually. Lodge online through myGov, your accounting software, or your BAS agent.

All calculations are performed in your browser — your data never leaves your device. Results are for general guidance only and should not be considered professional financial advice.

Built and maintained by Konstantin Iakovlev. Data sourced from the ATO and official Australian government sources.

People Also Use

Income Tax Calculator 2025-26

Tax

GST Calculator

Tax

HECS-HELP Repayment Calculator

Tax

Tax Return Estimator

Tax

Pay Calculator

Pay & Salary

Hourly to Salary Calculator

Pay & Salary