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Calculating your GST

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Most people file their GST return in myIR which does the calculations for you. If you file a paper return the form tells you what calculations to make.

Regardless of how you file you need to work out your total:

  • sales and income
  • zero-rated supplies
  • debit adjustments
  • purchases and expenses
  • credit adjustments

Sales and income

The way you work out your total sales and income depends on the accounting basis you use.

You use the invoice or hybrid basis You use the payments basis

Add up all the invoices you issued for your taxable supplies during the taxable period. Then, add any payments received for taxable supplies during the taxable period that you have not already accounted for.

Add up all the payments you received for your taxable supplies during the taxable period.

Zero-rated supplies

Add up all your zero-rated supplies for the taxable period.

Zero-rated supplies

Debit adjustments

Add up all your debit adjustments for the taxable period.

GST debit adjustments

Purchases and expenses

The way you work our your total purchases and expenses depends on the accounting basis you use.

You use the invoice or hybrid basis You use the payments basis

Add up all the invoices you've received for purchases and expenses that include GST during the taxable period. Then, add any payments made for purchases and expenses that you have not  already accounted for.

You must have tax invoices for these purchases and expenses.

Add up all the payments you made for purchases and expenses that include GST during the taxable period.

You must have tax invoices for these purchases and expenses.

You can only claim part of the GST charged on a purchase that will not be exclusively used in your business.

GST adjustments for business or private use

Credit adjustments

Add up all your credit adjustments for the taxable period.

GST credit adjustments

GST to pay or refund?

myIR will tell you how much GST you have to pay or will be refunded. If you file a paper return, the form tells you what calculations to make.

Paying GST

GST refunds