Provisional tax periods and the 2026 deadlines

Zeynep Hanım the hairdresser's seasons

The rules described in this lesson are those of Turkish law.

Zeynep Hanım's hair salon has its seasons: June is wedding season, December is New Year, February is quiet. Her appointment book tells her in advance which months will be busy. Last year her salon moved to real taxation; a new season was added to her book: provisional tax, which comes every three months.

This year at the start of February her mali müşavir (accountant) reminded her: "On the 17th, provisional tax for October–December is due." Zeynep Hanım was surprised: "I read online that the fourth period was abolished." That was true once. Not any more.

We saw what provisional tax is in the lesson What is provisional tax, and who pays it?. Here we look at its calendar.

Four periods a year

The calendar year is divided into four quarters. At the end of each quarter comes one return and one payment.

The rule: by the evening of the 17th of the second month after the period. The return and the payment have the same deadline. Even if there was no profit in that period, or even a loss, the return is still filed. This day has applied since GİB's 2019 arrangement (VUK Circular No. 115, 115 Sıra No'lu VUK Sirküleri); if the days ever change again, it will show in the GİB calendar.

If the last day falls on a weekend or a public holiday, the deadline ends on the first working day after it (Tax Procedure Law, Vergi Usul Kanunu, art. 18). This happened in the first period of 2026: because 17 May was a Sunday, the deadline was 18 May. If you want to see it together with the month's other tax days, look at the lesson A month's calendar.

The date 17 February 2027 was worked out from the rule; once GİB publishes the 2027 calendar, confirm it there too.

The fourth period: abolished, then back

• 2022–2024: With Law No. 7338, provisional tax for the last period had been abolished. There were three returns a year; October–December profit was calculated directly in the annual return.
• From 2025 onwards: Law No. 7566 (Official Gazette 19 December 2025) removed the "first nine months" limit in GVK repeated art. 120. The change applies to periods starting from 1 January 2025. That is why the October–December period of 2025 was also declared; according to the GİB announcement, the normal deadline was 17 February 2026. For taxpayers in the earthquake region whose force majeure status ended on 30 November 2025, the deadline was extended to 9 March 2026.
• 2026: Once again there are four periods.

You will still come across articles online saying "there is no fourth period"; most of them describe the 2022–2024 rule. Before trusting an article, check the date of the law it relies on.

The calendar is the same for companies. Only for companies whose accounting period differs from the calendar year (a special accounting period) do the days shift; if you have such a company, your mali müşavir will know.

February and March, back to back

The return of the fourth period has a consequence on the cash side. In February comes provisional tax for October–December, in March the annual return and its first instalment (for a company, the corporate tax return is in April). The amount in March is what is left after deducting the provisional tax you paid in February; in other words, the two are parts of the same tax. Still, because the two payments come about six weeks apart, the money to set aside needs to be planned from December.

The fourth period also has one convenience. Its tax base (matrah), that is, the profit the tax is calculated on, is the profit from the start of the year to the end of December; the same year the annual return covers. When your mali müşavir closes the books in January, they prepare both jobs from the same documents. Sending December's documents in the first week of January makes both February's provisional tax and March's annual return easier.

What happens when a period ends?

Think of October 2026: the July–September period has closed, and its calculation is being done now. The flow usually goes like this:

The period's profit is calculated from documents. A purchase invoice that has not arrived after the period ends makes expenses look too low; a forgotten sales invoice makes profit look too low. Sending the documents as soon as the period closes is the easiest way to get the figure right.

Zeynep Hanım added four lines to her calendar: 18 May, 17 August, 17 November, 17 February. One week before each, she also put a note: "ask the mali müşavir for the amount". February was not quiet this year, but there were no surprises either.

If you are under simplified taxation, none of the lines in this calendar concern you; there is no provisional tax.