PAYG instalment calculator (instalment rate method)

If you pay PAYG instalments with the instalment rate (option 2 on your BAS), the amount you pay is your instalment income (T1) × your instalment rate (T2), or × your varied rate (T3) if you've varied it. The result goes at T11 and at 5A.

Everything runs in your browser. Nothing you type is sent anywhere or saved.

How it works

1. Put your instalment income for the period at T1, in whole dollars.
2. Your rate is pre-filled at T2 (the ATO works it out from your latest tax return as estimated tax ÷ instalment income × 100). If you've varied the rate, use T3.
3. T1 × T2 (or × T3) = T11. Write that amount at 5A.

ATO worked example: instalment income $106,000 × 11% = $11,660. Try it above.

Option 1 or option 2?

• Option 1, instalment amount: the ATO calculates a fixed amount for you (based on your last return, adjusted for GDP growth). Nothing to work out; you pay what's on the notice.
• Option 2, instalment rate: you multiply your actual income by a rate, so payments go up and down with your income. The ATO suggests it if your income changes a lot.
• If you choose option 1 on your first statement for the year, you stay on it for the rest of that income year; you can switch to option 2 from the first quarter of the next year.

Rounding: the BAS labels T1, T11 and 5A take whole dollars (the form pre-prints “.00”). This calculator drops the cents from T1 before multiplying, then drops the cents from the result. Use the figure on your own statement if it differs.

Sources (checked 17 Oct 2026): ATO Calculate your PAYG instalments (options 1 and 2, T1 × T2 = 5A, the $106,000 × 11% example); How we calculate your PAYG instalment amount or rate; Instalment income; Who can pay using the instalment amount; ATO quarterly BAS form (T1, T2, T3, T11, 5A).

General information, not tax advice. It doesn't take your circumstances into account, and it can't tell you whether to vary your instalments. Check with the ATO or a registered tax agent.

Related

• BAS due date calculator FY2026-27 (when 5A is due) · GST calculator
• Article: BAS G1, 1A and 1B explained for sole traders
• Paid spreadsheet: GST & BAS Workbook FY2026-27 · Free: BAS quarter checklist (PDF)