17 May, 17 August, 17 November and 17 February: provisional tax calculation, offset and common mistakes.
Provisional tax is the part of annual income and corporate tax that is prepaid during the year. It prevents a single large tax bill at year end and balances the government's cash flow. Here are the periods, the logic of calculation and the payment calendar.
Periods and dates
Provisional tax periods are three months each:
- January – March period: filing and payment by 17 May
- April – June period: by 17 August
- July – September period: by 17 November
- October – December period: by 17 February (corporate taxpayers have no fourth period; it is included in the annual return)
If the date falls on a weekend or holiday, the deadline extends to the next business day.
Calculation logic
The provisional tax base is found from cumulative trading profit from the start of the year to the end of the period. Provisional tax calculated in the previous period is offset. For income tax payers the first bracket tariff applies, while corporate tax payers use the corporate tax rate.
Example: a limited company earned cumulative profit of 800,000 TRY in January–June and paid 100,000 TRY provisional tax in the first period. At a 25% corporate tax rate, the period's provisional tax is 800,000 × 25% = 200,000 TRY; the 100,000 TRY paid earlier is offset and 100,000 TRY is paid.
Offset and refund
The total provisional tax paid during the year is offset against the tax computed in the annual return. If provisional tax is excessive, the difference can be offset against other tax debts or a refund can be requested. Loss-making businesses file but do not pay.
Common mistakes
- Filing before period-end entries (depreciation, exchange differences, provisions) are complete
- Determining the base without stock count and cash reconciliation
- Forgetting to pay: even if the return is filed on time, a late surcharge applies if payment is not made
- Delays in e-ledger certification
How it works in our office
For our clients, provisional tax is calculated with a period-closing checklist, the estimated tax amount is shared in the portal before the deadline and the accrual slip is archived. For cash planning, the next period's provisional tax estimate is included in the monthly report.