Key 2026 Tax Dates: The Business Owner's Calendar

You run a company subject to corporate income tax (IS), you pay yourself a salary, you may employ one or two staff, and you file VAT. Every month has its deadline, and a delay, even of 48 hours, triggers penalties that are far from trivial. This calendar is not just a list of dates: it is the tool we use to plan our clients' cash flow and avoid the nasty surprises of May and December.

A director's key 2026 deadlines cluster around a few peaks. For an IS company with a 31 December 2025 year-end, the annual tax package is due on 4 May 2026 (paper or EFI filing) or 19 May 2026 by EDI transmission, the IS balance on 15 May, and the IS instalments on 15 March, 15 June, 15 September and 15 December. The CFE business property tax is due on 15 December.

Most published calendars mix every obligation together without a hierarchy. In practice, a small or mid-sized business owner needs to see three things at once: what the company owes, what they must declare personally, and what weighs on cash flow in the same month.

Our approach here is to combine those three layers. You will not find an exhaustive inventory of every existing tax, but the essentials for a director who wants to plan ahead. For the technical, line-by-line detail, refer to our detailed 2026 tax deadlines calendar, which complements this planning schedule.

Our reading#

The real issue in 2026 is not knowing the dates, which are public, but understanding their cumulative effect on cash flow. Two months concentrate the pressure: May (IS balance, tax package, the June instalment approaching) and December (IS instalment, CFE, VAT balance, sometimes a bonus). A director who has not set aside reserves for these two peaks ends up overdrawn while the business is profitable. It is the most common mistake we correct at the start of an engagement.

Here are the recurring milestones for an IS company with a 31 December year-end, a paid director and at least one employee. VAT and payroll (DSN) dates vary with your regime and headcount: always check your exact date on your professional account.

Monthly VAT (standard regime) and DSN recur every month: these are the two obligations to automate first, because they generate the most penalties for simple calendar oversights.

Corporate income tax: four instalments and a balance#

An IS company normally pays four instalments, due on 15 March, 15 June, 15 September and 15 December 2026. The balance is due on the 15th of the fourth month following the year-end, so 15 May 2026 for a 31 December 2025 year-end.

Instalments are calculated on the last known year's result. If your 2025 result rose sharply, your 2026 instalments increase mechanically: a point to watch for growing companies, which must set aside more than the previous year.

The tax package: 4 May or 19 May 2026#

The statement of results, better known as the tax package (liasse fiscale), is the central act of the year-end. For a 31 December 2025 year-end, it must be filed no later than 4 May 2026 by paper or EFI mode. Companies transmitting via EDI receive an additional 15 calendar days, moving the deadline to 19 May 2026.

In concrete terms, the tax authority uses the 2nd working day following 1 May as the baseline deadline, then adds 15 days for transmission. Almost all companies supported by a firm file by EDI: the operational date to remember is therefore 19 May 2026. For the detail by year-end date, see our tax package filing deadlines according to your year-end.

CFE: 15 December 2026#

The business property tax (CFE) is due no later than 15 December 2026. The notice is not posted by mail: it is made available in your professional account, usually in the autumn. This is a classic trap for young companies, which wait for a letter that never arrives and discover the deadline late.

The income tax return#

Your director's salary, dividends and any rental income are declared in spring, on a calendar staggered by geographic zone. The exact dates are published each year by the tax authority, generally for filings between late May and early June depending on your department. Plan ahead on dividends: the salary-versus-dividend trade-off is prepared before the year-end, not at filing time.

We cover this in detail in our article on the director's income tax return in 2026, which usefully complements this calendar.

Withholding tax#

If you are on withholding via instalments (majority director income, for example), remember to update your rate after any significant change in pay. A non-updated rate creates either a needless cash-flow effort or a catch-up the following year.

If you employ staff, the DSN (nominative social declaration) is monthly. Depending on your headcount, the filing and payment of contributions fall on the 5th or 15th of the month following the employment period. For a director treated as an employee, contributions follow the same rhythm as payroll. For a self-employed director (TNS), Urssaf deadlines are monthly or quarterly depending on your option.

Payroll is the area where a calendar error costs the most, because it combines a social risk with the risk of an Urssaf audit. That is why we recommend outsourcing or securing the management of payroll and social declarations from the very first employee.

The risk directors most underestimate is not missing an isolated date: it is the domino effect of May. Over a few weeks, the IS balance, the tax package, the June IS instalment and the personal income tax return all pile up. A profitable but under-provisioned company can find itself stretched precisely when it pays its tax.

The fix is simple but must be set up early: each month, set aside a fraction of the estimated IS in a dedicated account, and schedule a cash-flow review in March to anticipate the May peak.

Should you pay each deadline at the last minute to preserve cash, or act ahead to play it safe?

Our view: for VAT and DSN, automate and pay on the due date, with no risky cash-flow games, because these penalties are the fastest to hit. For IS and the tax package, get ahead on preparation (year-end closed in March) while settling the balance on the due date. You gain peace of mind without giving up your cash. The only case where playing for time is justified is genuine strain, and you should then arrange a staggered plan with the tax authority rather than incur a surcharge.

1. In January, list your year's deadlines in a shared table with your firm.
2. Each month, check VAT and DSN before the 5th, then before the 15th depending on your regime.
3. In March, close the accounts and estimate the IS due to anticipate the May peak.
4. Each month, set aside a share of IS and CFE in a dedicated account.
5. In November, check your professional account for the CFE notice.
6. Run a half-yearly cash-flow review, in May and December.

A company that does not close on 31 December sees all its IS and tax package dates shifted: the IS balance and the statement of results then follow the rule of the 15th of the fourth month after the year-end, and the 2nd working day following 1 May applies only to 31 December year-ends. A newly created company may be exempt from IS instalments in its first year. A self-employed director follows an Urssaf calendar distinct from the DSN. In all these cases, the standard calendar is not enough: it must be recalculated for your situation.

• For a 31/12/2025 year-end, the tax package is due on 4 May 2026 (paper/EFI) or 19 May 2026 (EDI).
• The IS balance is due on 15 May 2026; instalments on 15 March, 15 June, 15 September and 15 December.
• The CFE is due on 15 December 2026, on an online notice you must retrieve yourself.
• VAT and DSN are monthly: these are the deadlines to automate first.
• Two cash-flow peaks to anticipate: May and December.
• Dates vary with your year-end, your VAT regime and your headcount: have your personalised calendar validated.

This calendar informs and sets the framework; it does not replace a review of your situation. Your exact dates depend on your regime, your year-end and your headcount. To secure your 2026 schedule and plan your cash flow, our firm supports you on corporate tax and payroll. You can also read our guide to SME accounting obligations for the overall picture.