How to File GST F5 in Singapore: A Plain-English Guide for SMEs

Confused by GST F5? This step-by-step guide explains what to report, how to calculate your output and input tax, and how Claify makes the whole process faster.

If you run a GST-registered business in Singapore, you need to file a GST F5 return with IRAS every quarter. For many SME owners, this is one of the most stressful parts of running a business — not because it is complicated, but because the terminology can be confusing.

This guide explains exactly what you need to do, step by step.

What is the GST F5?

The GST F5 is the standard GST return form that GST-registered businesses in Singapore submit to IRAS. You declare:

Output tax — the GST you collected from your customers
Input tax — the GST you paid to your suppliers
The net amount you owe to IRAS (or are owed as a refund)

If your output tax exceeds your input tax, you pay the difference to IRAS. If your input tax is higher, you can claim a refund.

Who needs to file GST F5?

Any business registered for GST in Singapore must file F5 returns. You are required to register if your taxable turnover exceeds $1 million in a 12-month period.

Even if your business has zero transactions in a quarter, you must still file a nil return.

When is the F5 due?

GST F5 returns are filed quarterly. The due date is one month after the end of each accounting period.

For example, if your GST accounting period runs January–March, your F5 is due by 30 April.

IRAS can impose a late filing fee of $200 and further penalties if you miss the deadline.

What you need before you start

Before you log into myTax Portal to file, gather:

Total value of standard-rated supplies (sales where you charged 9% GST)
Total value of zero-rated supplies (exports, international services)
Total value of exempt supplies (if any — mainly financial services)
Total value of purchases and expenses with GST incurred
Total input tax claimed

If you use Claify, all of this is pre-calculated on your GST Report page — go to Reports → GST F5.

Step-by-step: filing your F5

Step 1 — Log in to myTax Portal

Go to mytax.iras.gov.sg and log in with your Singpass.

Step 2 — Navigate to GST returns

Under GST, select File GST Return (F5/F8).

Step 3 — Fill in Box 1–7

The F5 has seven boxes. Here is what each one means:

Box	Label	What to enter
1	Total value of standard-rated supplies	Revenue where you charged GST at 9%
2	Total value of zero-rated supplies	Revenue from exports or international services
3	Total value of exempt supplies	Revenue from exempt items (e.g. residential rent)
4	Total value of taxable purchases	All your business expenses with GST
5	Output tax due	Box 1 × 9%
6	Input tax and refunds claimed	GST you paid on Box 4 purchases
7	Net GST payable / claimable	Box 5 minus Box 6

Step 4 — Review and submit

Double-check the numbers before hitting Submit. IRAS will send an acknowledgement instantly.

Step 5 — Pay (if you owe)

If Box 7 shows an amount payable, settle it by the due date via GIRO, PayNow, or AXS.

Common mistakes to avoid

Claiming input tax on private expenses — only business expenses qualify
Missing zero-rated supplies — exports must still be declared in Box 2
Forgetting to include overseas digital services — B2B digital services imported from overseas may be subject to GST
Late filing — even a nil return must be filed on time

How Claify helps

Claify automatically tracks your GST on every invoice and expense. Before filing, go to Reports → GST F5 to see all seven box values pre-calculated. Copy the numbers directly into myTax Portal — no spreadsheet required.

If you are not yet on Claify, sign up free and import your bank transactions via CSV to get started.