IS installments: calendar and calculation 2026

IS installments are due from any company subject to corporate tax whose reference tax reaches 3,000 euros. Each installment equals one quarter of the IS of the last closed financial year, paid on March 15, June 15, September 15 and December 15 via statement no. 2571, with the balance due the following May 15.

Update of April 5, 2026 - Corporate tax advance payments represent one of the first tax cash outflow items for subject companies. In 2026, a company subject to IS must pay four quarterly installments, each calculated on the basis of the référence tax for the previous financial year. Failure to comply with the schedule or a calculation error exposes you to surcharges and late penalties.

IS installments are due from all companies liable to corporate tax, except where the reference IS (that of the last closed financial year) does not exceed 3,000 euros: in that case the company is exempt from paying (article 1668, 1 of the CGI). No turnover threshold of 2.3 million euros governs this obligation. Each installment equals one quarter (25%) of the reference IS, so the four payments together represent about 100% of that tax. The electronic payment schedule imposes specific deadlines, generally the 15th of the third, sixth, ninth and twelfth month of the current financial year.

An IS deposit is an advance payment of corporate tax. The mechanism is provided for by article 1668 of the General Tax Code (CGI). The idea is simple: the State does not want to wait for the end of the financial year and the submission of the tax return to collect part of the tax. Advance payments allow tax revenue to be smoothed throughout the year.

The calculation is based on a référence: the corporate tax due for the financial year preceding the current one. This référence tax serves as the basis for calculating each installment. Each installment equals one quarter (25%) of this reference tax: the four payments combined therefore represent about 100% of the corporate tax for the reference year.

To complete, see Taxation and déclarations: VAT, IS, advance payments, Tax package submission deadline 2026 and Taxation and company taxes.

Almost all companies subject to IS pay installments. The only general exemption covers companies whose reference IS does not exceed 3,000 euros, and newly created companies. The mechanism is set by article 1668, 1 of the CGI.

The 3,000-euro reference IS exemption#

The obligation to pay installments does not depend on a turnover threshold. A company is exempt from paying when its reference IS (the tax of the last closed financial year) does not exceed 3,000 euros (article 1668, 1 of the CGI; BOFiP BOI-IS-DECLA-20-10, § 360). As soon as the reference IS reaches 3,000 euros, the four installments become due, whatever the level of turnover.

Newly created companies#

Companies created during the current financial year are not subject to the obligation to make advance payments for their first financial year. In fact, they do not have any previous référence exercise. This exemption ceases from the second financial year, if the turnover threshold is reached.

Corporate groups#

Each company in the group is assessed individually against its own reference IS: there is no consolidation of turnover for the installment obligation. Two turnover thresholds, distinct from that obligation, nonetheless exist: the 3.3% social contribution is only due above 7,630,000 euros of turnover (article 235 ter ZC of the CGI), and the increased final installment concerns companies whose turnover reaches at least 250 million euros (article 1668, 1 of the CGI).

Quick decision: do you have to pay IS installments?#

Source: article 1668, 1 of the CGI; BOFiP BOI-IS-DECLA-20-10.

The schedule of installments is set by article 1668 of the CGI and the administrative doctrine of the DGFiP. For the financial years ending December 31, the four deadlines are as follows:

First installment: March 15, 2026#

The first payment occurs during the third month of the financial year. For a financial year aligned with the calendar year, the deadline falls on March 15, 2026. This first payment is often the most difficult to anticipate, because it occurs before the company even has a clear vision of its results during the year.

Second installment: June 15, 2026#

The second payment is due June 15, 2026. On this date, the company generally has the results for the closed financial year and can begin to adjust its forecasts for the current year.

Third installment: September 15, 2026#

The third installment is due on September 15, 2026. It is often at this deadline that companies notice a gap between the deposits paid and the actual expected result.

Fourth installment: December 15, 2026#

The final installment is due December 15, 2026. It closes the advance payment cycle. The balance of IS will be paid when the tax package is submitted, generally in May 2027 for financial years ending December 31.

Exercises not aligned with the calendar year#

The four installments remain payable on fixed calendar dates: March 15, June 15, September 15 and December 15 (BOFiP BOI-IS-DECLA-20-10, § 60). For a financial year that does not coincide with the calendar year, it is the order of the installments that depends on the closing date, not the dates themselves. This sequencing must be reviewed as soon as a change in closing date occurs.

The calculation of advance payments is based on a precise mechanism defined by article 1668 of the CGI.

The basic formula#

The total amount of installments equals the reference corporate tax (that of the last closed financial year), divided into four equal payments: each installment therefore represents one quarter of that tax (BOFiP BOI-IS-DECLA-20-10, § 110).

Amount of each installment = reference-year IS ÷ 4 (i.e. 25% of that IS)

Concrete example#

Let's take a SAS whose corporate tax due for the 2025 financial year amounts to 50,000 euros. The calculation is as follows:

• Total amount of installments: 50,000 euros (the full reference IS)
• Amount of each installment: 50,000 ÷ 4 = 12,500 euros The company will have to pay 12,500 euros on each of the four deadlines in 2026, i.e. 50,000 euros in total.

The case of the reduced IS rate#

SMEs whose turnover excluding taxes is less than 10 million euros and whose capital is at least 75% held by individuals benefit from the reduced corporate tax rate of 15% on the fraction of profit not exceeding 42,500 euros (article 219-I-b of the CGI). This reduced rate also applies to the calculation of the référence tax serving as a basis for advance payments.

The impact of social contribution on profits#

The 3.3% social contribution on IS (article 235 ter ZC of the CGI) only applies to companies whose turnover reaches 7,630,000 euros, with an allowance capped at 763,000 euros. When it is due, it is included in the reference IS used as the basis for the four installments.

The law provides for adjustment mechanisms to prevent advance payments from becoming disproportionate to the actual result.

The ability to modulate downwards#

Article 1668, 4 bis of the CGI allows the company to modulate downwards the amount of its installments when it estimates that the corporate tax for the current financial year will be lower than the installments already paid. This modulation must be justified by objective éléments: drop in activity, exceptional loss, change in structure.

Modulation is carried out directly during electronic payment on the impôts.gouv.fr portal. The company declares an amount lower than the automatic calculation. Please note: if the modulation proves excessive, the shortfall in installments is penalised by the 5% surcharge of article 1731 of the CGI, plus late-payment interest of 0.20% per month (article 1727 of the CGI), calculated on the difference between the installment due and the installment actually paid.

The capping of deposits#

The total amount of advance payments cannot exceed the amount of corporate tax actually due for the current financial year. If the advances paid exceed the final tax, the excess is chargeable to the IS of the following financial years or, failing that, refundable. This limitation of installments to the estimated tax comes under article 1668, 4 bis of the CGI.

Additional deposits#

In certain cases, the company may be required to pay additional deposits. This is particularly the case when it has exercised an option for a différent tax régime or when it has carried out an exceptional transaction having a significant impact on its tax result.

Representative example: modulating without getting caught#

An SME closes 2025 with a reference IS of 40,000 €, i.e. 2026 installments of 10,000 € each. From the first half-year, its order book falls sharply and the forecast points to a 2026 IS of around 24,000 €. It then reduces its September and December installments to stay within that estimate, keeping the costed forecast and the interim trial balance that justify it.

This scenario, common in closing files, illustrates the rule of article 1668, 4 bis of the CGI: modulation is a right, but an estimate that is too low exposes the company to the 5% surcharge (article 1731 of the CGI) and to late-payment interest. What protects the director is the dated document underpinning the estimate.

Payment of IS installments is made exclusively by telepayment on the professional portal impôts.gouv.fr. Payment by check or free transfer is no longer accepted for this tax.

The electronic payment procedure#

The company connects to its professional space on impôts.gouv.fr using its identifiers. She selects the "Pay" section then "Corporate tax". The system automatically calculates the expected deposit amount. The company can confirm it as is or modify it if it meets the conditions.

Payment must be made no later than the due date. A payment made the same day is considered regular, but it is recommended to anticipate at least two working days to avoid technical hazards.

Late penalties#

In the event of late payment, the administration applies an increase of 5% to the amount of the deposit not paid or paid late, in accordance with article 1731 of the CGI. This increase is due automatically, without the administration having to send any prior notice. Late payment interest at the rate of 0.20% per month is added to this increase.

Forms and deadlines: what to remember#

Payment is made exclusively by electronic payment on impots.gouv.fr. Return no. 2065 establishes the result, but it is not the instrument for paying the balance.

Source: impots.gouv.fr (forms 2571-SD and 2572-SD); BOFiP BOI-IS-DECLA-20-20.

**Our firm's experience reveals several recurring errors in the management of IS deposits.

Assuming you are exempt without checking the reference IS#

Some companies wrongly believe that a turnover threshold exempts them from installments. The only general exemption relates to a reference IS below 3,000 euros. As soon as the tax of the last closed financial year reaches that amount, the four installments become due, without any prior notice from the administration.

Neglect modulation#

Many companies mechanically pay the four installments without checking whether their current results justify this level of payment. In a context of declining activity, this rigidity can weigh heavily on cash flow.

Confusing installments and IS balance#

Deposits do not constitute the final payment of the IS. The balance is determined from the results return (form no. 2065), but it is paid via balance statement no. 2572, at the latest on May 15 following a December 31 closing. If the deposits are insufficient, a supplement is due. If they are excessive, a tax credit is recognized.

Not anticipating structural changes#

A merger, a split or a change in closing date modifiés the calendar and the calculation of deposits. These operations must be reported to the corporate tax service (SIE) to avoid double taxation or omissions.

Hayot Expertise Advice: An IS deposit is not just a tax line. It's a budgetary signal. Well anticipated, it improves visibility. Poorly followed, it degrades cash flow without warning. We recommend that our clients review the advance payment forecast at each interim closing, not just at closing.

The management of IS deposits must be part of an overall cash flow management approach.

Integrate down payments into the cash flow plan#

From the opening of the financial year, the four installment deadlines must be included in the forecast cash flow plan. Each installment must be provisioned monthly to avoid tensions at the time of maturity.

Revise forecasts at each closing#

A quarterly or half-yearly statement makes it possible to compare the actual result with the initial forecasts. If the difference is significant, modulation of the remaining installments must be considered. This regular review is the key to effective tax management.

Anticipate the IS balance#

The installments represent about 100% of the IS of the reference financial year. When the result grows, the balance can be substantial: it is paid via balance statement no. 2572, at the latest on May 15 following a December 31 closing. It is prudent to provision monthly the difference between the installments paid and the estimated IS for the current financial year.

We integrate IS installments into a cash flow calendar and tax management consistent with your financial year.

Manage your IS deposits with precision

In 2026, corporate tax payments must be read as a component of the financial management of the company, not as an isolated formality. Respecting the schedule, the accuracy of the calculation and the ability to modulate according to the actual result are all levers which protect cash flow and avoid penalties. A company that controls its advance payments controls a significant part of its tax planning.

(Official sources: impots.gouv.fr, installment statement no. 2571 and balance statement no. 2572; General Tax Code, articles 1668, 219-I-b, 235 ter ZC, 1727 and 1731; BOFiP BOI-IS-DECLA-20-10 and BOI-IS-DECLA-20-20)