
26 October 2026
By Dr. Hamed Molatefi, tax adviser · Reviewed 26 October 2026
Short answer
The VAT return deadline is 15 days after the end of each quarter, and an amended return is possible only until that deadline ends. Miss it, and you can no longer amend that return; the authority may, under the regulations, assess tax or impose a penalty. Take the rate from the official system or your adviser. Read the exact day for each period from the authority's notices and the compliance calendar, not from memory.
As each quarter ends, several taxpayers call to ask what happens if they file the return late. Let me be clear from the start: the VAT return deadline is short, and the window to amend that same return closes when this deadline ends. Drawing on our experience supporting small and medium-sized businesses, I will set out what this deadline means, what late filing does, and how to arrange the rest of the year's deadlines so you are not caught out. Wherever I am not certain of a rate or a circular, I will not invent a figure, and I will refer you to the official system.
How long is the VAT return deadline?
The deadline for filing the VAT return is 15 days after the end of each quarter. After spring, summer, autumn, and winter you have a short window, not a full month to put the documents in order. This is not an annual obligation; it falls four times a year, and each period stands apart from the one before.
Do not write the last day from memory. The length of Esfand, a public holiday, and sometimes a notice can change the day you need to act. For that period, check the tax compliance calendar and take the notices on the Iranian National Tax Administration information portal as your guide. If your period of activity differs from the usual pattern, check that same source with your adviser.
I often hear one mistaken view: that you can amend the return until the authority has said something. That is not the case. An amended return is possible only until the end of the legal deadline for filing that return. If you spot the error within those same 15 days, you still have time. Once the deadline ends, that door closes, and a simple amendment no longer helps.
Why does the work slip to the last days?
Card-reader reports, invoices, and the bank reconciliation are usually not ready on the first morning of the deadline. If you wait until the second week for every figure to be final, half the window is gone. In our advisory work we have made it a habit to start the close a few days before the quarter ends. We flag pending items separately and close the rest; holding the entire job does not extend the deadline.
What happens if you miss this deadline?
In late-filed cases I have almost always seen two effects, and I will not state either as a fixed percentage. The first is clear: you lose the ability to amend that return. The second is that the authority may, in accordance with the regulations, assess tax and impose a penalty for late filing or failure to file. Ask the Iranian National Tax Administration, or that quarter's adviser, for the details.
Do not treat a late return as the same thing as a tax assessment notice (barg-e tashkhis). The assessment notice is a later stage. If it is served, under Article 238 of the Direct Taxes Act you have 30 days from the date of service to attend or file an objection, after which it becomes final. Before any rushed call, read A tax assessment notice has arrived; what should you do before anything else?. Those 30 days are a live deadline too, and “I'll call next week” can mean losing the right to object.
Some people, once they are late, prefer to send nothing so they do not draw attention. That assumption is dangerous. Silence does not restore the deadline, and it usually makes the figures harder to explain. The right step is to clarify, that same week, the status of the tax file and the obligation for that period. Also see the common errors in Mistakes that make a return fragile, so a late filing is not tied to an error-filled return.
Set the year's other deadlines alongside VAT
If only VAT is on the calendar, next spring will catch you out. For business owners, the income tax return deadline and the Note 100 route both run until the end of Khordad the following year. Note 100 is not an exemption from electronic invoicing, and it is not necessarily worthwhile for every business. Before you choose, read Points to consider on Note 100 for business owners.
Legal entities have a separate calendar. Their return deadline is four months after the end of the financial year, and for a year ending in Esfand it runs until the end of Tir. Do not compare a company with a shop. Mixing up these two dates is a recurring error in files that include both an individual and a company.
Quarterly transactions under Article 169 are due 45 days after the end of the quarter. This obligation is separate from the VAT return. Missing the 15-day deadline does not cancel the 45-day obligation, or the other way around. Many calls in the third week of the following month come precisely from mixing up these two deadlines.
Electronic invoicing has no annual deadline, and the obligation has been rolled out in stages, through calls issued by the authority. Do not assume every company or every business is required to comply. If you are unsure, the tax file and the authority's notice are the guide, not your trade peers. Read the text of the laws on the National Laws and Regulations System so you do not rely on an outdated quotation.
A simple order to remember
After each quarter, VAT has 15 days and quarterly transactions have 45 days. The following year, business owners have until the end of Khordad, and companies with an Esfand year-end have until the end of Tir, for the income tax return. A tax assessment notice (barg-e tashkhis) has a separate 30-day deadline from the date of service. Put these four lines on paper; in the rush of sales, the mind swaps the dates.
A practical example from a hypothetical file
This is a hypothetical example and does not refer to any real person or shop. Suppose the owner of a home-appliance store has closed the summer with a mix of card-reader sales and several wholesale invoices. They receive the gateway report on the fifth day of the following month. On the tenth day they find that a corporate buyer was left out of total sales and that a sales return was posted twice.
If they amend by the end of the 15-day deadline, they are still within the VAT return deadline and an amendment is possible. If the work slips to the third week, that door has closed. In this hypothetical example the gap is only a few days, but the ability to amend is entirely different.
Steps in this hypothetical example
Step one: three days before the quarter ends, they close the sales and purchase lists and note pending items separately, rather than holding the whole job. Step two: in the first week of the deadline, they reconcile total sales with the card reader and the bank. Step three: they correct the omission within that same deadline by an amendment.
Step four: they keep the filing date and the tax-file status so it is later clear whether the return was actually filed or only meant to be filed. Step five: they set a separate reminder for quarterly transactions so the 45-day deadline is not mixed up with the 15-day deadline. The same sequence works for a café or a service company; the difference is the volume of documents, not the logic of the deadline.
Habits that help you not miss a deadline
From late-filed cases, a few simple habits have worked better than complex tools. Keep a single calendar; reminders scattered between a partner and the accountant mean no one is responsible. Mark each deadline three times: ten days before to gather documents, three days before to review, and the morning of the filing day.
One person should be responsible for filing, and another should only confirm that the filing actually went through. In a small business, “the accountant was supposed to send it” is heard often after the deadline, and it restores no deadline. Do not leave filing to the last night. Do not leave setting up the unique fiscal memory ID and the filing method for the deadline day either. A dropped connection, or one missing digit in the final hour, cannot be put right.
Do not issue a test invoice. That option does not exist in the main tax file, and every invoice issued is real. Curiosity about how the system reacts can create a real invoice you will later have to explain. Also check new circulars on the Iranian National Tax Administration information portal so your internal calendar does not go stale.
Frequently Asked Questions
Is it a problem if I file the VAT return one day late?
The deadline is 15 days after the end of the quarter, and when it ends you can no longer amend that return. This article does not state a fixed rate for the financial effect of one day's delay; ask the authority's system or that period's adviser.
Can I amend the VAT return after the deadline has ended?
No. An amended return is possible only until the end of the legal deadline for filing that return. After the 15-day deadline, that route is closed.
Is the VAT deadline the same as quarterly transactions?
No. The VAT return is due 15 days after the end of the quarter, and quarterly transactions under Article 169 are due 45 days after the end of the quarter. Missing one does not remove the other obligation.
How does the return deadline for business owners differ from a company's?
Business owners and Note 100 have until the end of Khordad the following year. Legal entities have four months after the end of the financial year, and for a year ending in Esfand this deadline runs until the end of Tir.
Summary
The VAT return deadline is 15 days after each quarter, and an amendment is possible only until the end of that same deadline. Put the rest of the year's deadlines on one calendar, and take the penalty rate from the official system, not from memory. If you have missed a deadline, raise it with Forough Shomar Simorgh before you act in haste; book a time on the Book a consultation page, or email info@foroughshomar.ir.
Related articles
- What Is an Electronic Invoice and Who Must Issue It?
- Simple Guide to Registering in the Taxpayers' System for Small Businesses
- Tax Assessment Notice Has Arrived; What Should You Do Before Taking Any Action?
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