Every entry below is the rule as Saudi Arabia publishes it. It is a reference, not a calendar: where a deadline runs from something only you know, this page says so instead of showing a date.
This is the rule as published by the registry, checked against the primary source on the date shown. It is not your filing date. Where a deadline runs from incorporation, from a fiscal year the company itself elects, or from an event only you know about, no date can be derived here at all — the figure you see is the formula, not the answer. Extensions, transitional regimes and entity-specific exemptions are not reflected. Confirm with the registry before you rely on a date.
The company sets its own financial year. Article 16 of the Companies Law (Royal Decree M/132) provides that «A company's fiscal year shall be 12 months to be specified in its articles of incorporation or articles of association», with the first year allowed to run «not less than six months and not more than 18 months beginning from the date of the company's registration». Both tax clocks then hang off that elected year rather than off the calendar: ZATCA states that the zakat return and the corporate income tax return are due «within 120 days from the end of the tax year» (Article 102 of the Zakat Collection Implementing Regulations, Article 60 of the Income Tax Law), and the Companies Law requires the financial statements to be deposited «within six months from the date on which the fiscal year ends». Nothing in this entry can therefore be turned into a calendar date until the user supplies the year end. Two obligations here are the exception and do not touch the financial year at all: the annual confirmation of commercial register data runs on the register's own clock at the Ministry of Commerce, and the VAT return runs on the VAT tax period. A Saudi company with a June year end still files its VAT return by the last day of the month after each tax period.