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chapter four of six. Main types of finance.

Working out your GST refund or payment


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Small business guides > Quick guide to GST > Working out your GST refund or payment

Working out your GST refund or payment

When filing a GST return, most businesses must account for all of their purchases and sales. Let’s take a look at the maths you need to do, and some practical bookkeeping tips.

GST is a simple formula

You work out GST by comparing the amount you paid on purchases to the amount you collected on sales.

If you get a positive number, you need to pay that amount to the IRAS. If it’s a negative number, you’ll be refunded that amount.

As a GST-registered business:

  • you must submit your GST return to IRAS one month after the end of each prescribed accounting period, or quarterly
  • you should report both your output tax and input tax in your GST return
  • the difference between output tax and input tax is the net GST payable to IRAS or refunded by IRAS
How to work out GST

How to work out GST in four steps

1. Note the GST paid on your business purchases

How to work out GST you can claim

2. Note the GST collected on sales

How to work out GST you owe

3. Add both types of GST

Calculations for filing a GST return

4. Run the GST formula

GST formula

Avoid nasty surprises with smart bookkeeping

Like any business, you’ll aim to sell more than you buy. If you succeed in doing that, you’ll most likely end up with GST to pay. Run the four-step GST equation regularly so you can:

  • work out how big your GST payment is shaping up to be

Automate your GST calculations

Manage your GST filing with easy-to-use tax software.

Easily manage your GST F5 with Xero - IRAS-compliant software that makes it easy to stay on top of your tax obligations.

It automatically collects sales and purchase information from multiple sources, and does the maths for you. 


Chapter 6: GST returns and due dates

There’s no need to be confused about the GST filing process. We take you through simple and painless ways to file your GST in Singapore. 

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Everything you need to know about GST in Singapore.

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