Tax and Business Guide for Q3 2026

The third quarter is often associated with a summer slowdown and holidays. However, from a tax and accounting perspective, summer offers the ideal opportunity to evaluate your first-half performance, keep track of advance tax payments, and prepare for the autumn sprint. This guide from STING University provides a clear breakdown of all your obligations for Q3 2026, so you can enjoy your break without worrying about missed deadlines.

July: Tax Advisor Deadline and Summer Launch

For Beginners

• VAT Turnover Monitoring: Summer is a great time to review your total revenue. If your turnover for the past 12 consecutive months reaches 2,000,000 CZK, you must register as a VAT payer within 15 days following the end of the month via the Public Administration Portal.
• Flat Tax Regime: If you use the flat tax scheme, simply ensure your monthly advance is paid on time by the 20th of the month.

For Established Freelancers

• Tax Advisor Submissions: If a tax advisor prepares your return, the absolute deadline for electronic filing and paying income tax is July 1, 2026.
• Holiday Advances: Adjust your standing bank orders for social security and health insurance if your spring overview resulted in updated advance payment amounts.

For LLCs and Companies

• Audited Accounts: Companies subject to mandatory audits or using a tax advisor must submit their corporate income tax return by July 1, 2026.
• Q2 / June VAT: Filing of the VAT return and control statement is due on July 26, 2026 (since July 25 falls on a Sunday).

August: Post-Advisor Overviews and Mid-Year Audit

For Beginners

• Document Digitalization: Use quieter August days to organize your financial records. Moving to cloud accounting software will save you hours of manual work in the autumn.

For Established Freelancers

• Insurance Overviews (with Advisor): If you filed your tax return in July via an advisor, the deadline for submitting insurance overviews to ČSSZ and health insurance companies shifts to August 2, 2026 (as August 1 falls on a Sunday).
• Insurance Balances: Pay any outstanding insurance balances within 8 calendar days after submitting the overview.

For LLCs and Companies

• Mid-Year Financial Review: August is perfect for comparing your actual performance against your 2026 financial plan. Check your cash flow status before the busy autumn season starts.

September: Tax Advances and Autumn Preparation

For Beginners

• Autumn Prep: If you plan to launch new products or services, ensure your invoicing details and legal contracts are correctly set up.

For Established Freelancers

• Income Tax Advances: If your last known tax liability exceeded 30,000 CZK, you must pay your quarterly or half-yearly income tax advance by September 15, 2026, using the MOJE daně portal.

For LLCs and Companies

• Corporate Tax Advances: Corporate entities follow the same September 15 rule for advance tax payments based on their previous tax liability.
• Monthly VAT: The submission for August VAT is shifted from Saturday, September 25, to September 27, 2026.

Want to gain strategic perspective on finance, management, and tax optimization? Explore practical study programs at STING University and take your career to the next level.

Sources:

• Czech Social Security Administration. (2026). Deadlines for Freelancer Overviews. Retrieved from https://www.cssz.gov.cz/web/cz/osvc
• Financial Administration of the Czech Republic. (2026). Tax Calendar 2026. Retrieved from https://www.financnisprava.cz/cs/dane/danovy-kalendar
• Financial Administration of the Czech Republic. (2026). Income Tax Advances. Retrieved from https://www.financnisprava.cz/cs/dane/dane/dan-z-prijmu
• Ministry of Finance of the Czech Republic. (2026). MOJE daně Portal. Retrieved from https://www.adane.cz
• Public Administration Portal. (2026). VAT Registration Rules. Retrieved from https://portal.gov.cz