FBR Sales Tax Return Filing 2026-27: Step-by-Step Guide with Every Monthly Deadline

Every registered sales taxpayer in Pakistan must file a monthly return on the FBR IRIS 2.0 portal by the 18th of the following month, even if sales were zero. The first deadline of the new tax year was 15 August 2026; the next is 15 September for August returns. This is the complete, step-by-step guide to the sales tax return filing process for FY 2026-27, with the deadline calendar, common mistakes, and how to avoid the penalties that hit the unwary.

Sales tax registration and sales tax return filing are two different things. Registration is the one-time setup at the FBR; return filing is the recurring monthly obligation that every STRN holder owes. If you are registered for sales tax and you fail to file — even with zero sales — you owe penalties under Section 33 of the Sales Tax Act, 1990. The penalty is Rs 10,000 for the first default, Rs 20,000 for the second, and continues to rise with every missed cycle.

The 2026-27 sales tax filing calendar at a glance

The standard rule is the 18th of the following month. In practice, FBR issues a circular before each deadline that extends the date by one day when the 18th falls on a Sunday or a federal public holiday — which is why the August 2026 deadline slid from 18 August to 15 August in some accounts and to a different date in others. Always check the FBR circular for the exact date of the upcoming cycle.

What goes into a monthly sales tax return

The standard form for monthly sales tax filing is STR-1 (Supply of Goods and Services). The form has five core sections, and every registered taxpayer must complete all of them, even when the numbers are zero.

1. Output tax (sales). Total taxable sales for the month, broken down by rate (mostly 18%, with a few items at 5%, 10%, or 25%). The output tax is the sales tax you have collected from your customers.
2. Input tax (purchases). Total taxable purchases for the month, broken down by supplier and rate. The input tax is the sales tax you have paid to your suppliers. This is the credit side of your monthly position.
3. Adjustments. Any corrections from prior periods, supplier mismatches, credit notes issued or received, and any special adjustments under Sections 8, 9, or 10 of the Sales Tax Act.
4. Net payable. The arithmetic: output tax minus input tax minus adjustments. The result is either a payment (you owe FBR) or a refund (you carried excess credit). Most small retailers end up with a small payment each month.
5. Annex-C. The supplier-purchase register, where every purchase invoice is listed with the supplier’s STRN, invoice number, date, and tax amount. This is the most error-prone section, and the most common audit trigger.

How to file on FBR IRIS 2.0, step by step

1. Log in to IRIS. Go to iris.fbr.gov.pk and sign in with your STRN-linked NTN or CNIC. The same login works for income tax and sales tax.
2. Open the Sales Tax menu. From the left panel, click Sales Tax, then select Sales Tax Return (STR-1). The form will open with the current period pre-filled.
3. Select the period. Choose the month and year of the return. This is the period in which the transactions took place, not the date you are filing.
4. Enter output tax. Add up your sales for the month by tax rate. The standard rate is 18%, but check the latest Finance Act for any rate changes that took effect in the period.
5. Enter input tax and supplier details in Annex-C. Every purchase from a registered supplier needs to be entered with the supplier’s STRN, invoice number, date, and tax. Missing STRNs are the single most common reason for a return to be flagged.
6. Add any prior-period adjustments. If you under-reported or over-reported in a previous month, you can correct it here. Each correction should reference the original period.
7. Check the net payable. Review the arithmetic. If the system flags a mismatch, the return will not submit. Most mismatches are supplier-side (the supplier’s invoice does not match what they filed).
8. Generate a PSID and pay. If tax is payable, IRIS generates a Payment Slip ID. Pay through any bank, 1Link, mobile banking app, or ATM, and wait for the CPR (Computerised Payment Receipt) to reflect in your IRIS account.
9. Submit the return. Once the CPR reflects, click Submit, verify with your e-Pin, and download the acknowledgement. The acknowledgement is your proof of filing.

Common mistakes that trigger FBR scrutiny

• Missing STRNs in Annex-C. If you buy from a supplier and they don’t share their STRN, ask for it. Without it, your input tax is disallowed, and you pay more.
• Supplier invoice mismatch. If your supplier’s filed return does not include the invoice you are claiming, the system flags it. The most common reason is a supplier who has not filed their own return.
• Wrong rate applied. Some items are taxed at 5%, 10%, or 25% rather than the standard 18%. Using 18% for a 5% item is a common mistake that creates a refund demand the FBR will deny.
• Late filing with nil sales. “I had no sales this month” is not a reason to skip filing. A nil return is still a return, and missing it triggers a penalty under Section 33.
• Wrong period. Filing August 2026 sales in the September 2026 period creates a mismatch that takes months to correct.
• Mixing provincial and federal supplies. Supplies to unregistered persons, or supplies that attract provincial sales tax instead of federal, need to be in the right Annex or excluded from the federal return.
• Not keeping Annex-C for five years. The FBR can request Annex-C for any of the last five tax years. Many filers have it in IRIS but not in their own records.

Penalties and what to do if you have missed a deadline

There is also a separate penalty for non-filing of the annual or quarterly sales tax statements, which is Rs 50,000 for the first default. If you have missed one or more cycles, the cleanest fix is to file the missed returns (with nil figures if you had no sales) and then pay the penalty. The FBR will not refuse a late return, and the penalty stops growing once you are back in compliance.

If you are issued a show-cause notice under Section 11 of the Sales Tax Act, the case is handled by the adjudication officer and can lead to a formal order, additional tax, and further penalties. Resolving the show-cause at the earliest opportunity is usually cheaper than waiting for an order.

What is different in 2026-27

Three changes to the sales tax framework in the Finance Act 2026 are worth flagging for monthly filers.

• Expanded list of items at retail price. The list of items subject to sales tax on the retail price has been widened to include more confectionery, sauces, fermented beverages, household utensils, and certain plastic and ceramic products. If you sell any of these, your output tax calculation may be different from the previous regime.
• Withholding changes. Sales tax withholding on goods and services has been restructured under the WHT rate card for FY 2026-27. If you are a withholding agent, the rate you deduct at source may have changed.
• POS and digital-invoicing compliance. The 3% Section 21(r) digital-invoicing penalty remains in force, and the mandatory POS integration for retailers continues to be rolled out. Make sure your invoicing system is on the FBR-compliant list.

How to recover a forgotten STR-1 or correct a past return

1. Log in to IRIS and open the Sales Tax menu.
2. Select the period you want to amend (only the last few periods are editable directly; older ones need an amendment request).
3. Make the correction — for example, add a missed supplier invoice or fix a rate.
4. Resubmit the return. IRIS will recompute the net payable and any additional tax or refund.
5. If the period is outside the editable window, file a request under Section 21 of the Sales Tax Act for an amendment. FBR usually allows amendment for the last five tax years.

Frequently asked questions

What is the sales tax return filing deadline in Pakistan?

The 18th of the following month, or the next working day if the 18th falls on a Sunday or federal public holiday. FBR issues a circular before each cycle confirming the exact date.

What is the next sales tax return deadline for 2026?

15 September 2026 for August 2026 sales. The July 2026 deadline was 15 August 2026 and has already passed.

Do I need to file a sales tax return if I had no sales?

Yes. A nil return is still a return. Skipping it triggers a Section 33 penalty starting at Rs 10,000 for the first default.

How do I file the return?

Log in to iris.fbr.gov.pk, open the Sales Tax menu, select STR-1, complete the form including Annex-C, generate a PSID if tax is payable, pay through any bank or mobile app, and submit with your e-Pin.

What happens if I miss the deadline?

A Section 33 penalty applies: Rs 10,000 for the first default, Rs 20,000 for the second, Rs 50,000 per default from the third onwards. Continued non-filing can also lead to a sales tax registration suspension.

What is Annex-C?

The supplier-purchase register. It lists every purchase invoice in the month, with the supplier’s STRN, invoice number, date, and tax amount. Annex-C is the most common audit trigger because it cross-checks against the suppliers’ own filed returns.

Can I amend a return I already filed?

Yes. For the most recent periods, you can amend directly in IRIS. For older periods, you need to file an amendment request under Section 21 of the Sales Tax Act, which FBR typically allows for the last five tax years.

Where do I check whether I am registered for sales tax?

Log in to IRIS 2.0 at iris.fbr.gov.pk and look under the Sales Tax menu. Your STRN is also printed on the registration certificate issued when you first registered.