Overtime Hours: Salary Increase and Legal Calculation

Introduction

Overtime hours constitute one of the most closely scrutinised subjects in employment law by both employers and employees. Between calculating the applicable salary increase rate, respecting the annual limit, and the tax and social exemptions provided by law, the subject is both technical and evolving. A calculation error exposes the company to salary recalls, late payment penalties and, if applicable, to employment tribunal proceedings. This article guides you step by step through the current legal rules, concrete calculation mechanisms, and good practices in managing working time—including digital tools that secure the traceability of agreements.

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Legal Definition of Overtime Hours

What is an Overtime Hour?

In accordance with Article L. 3121-28 of the Labour Code, overtime hours are all hours of work carried out beyond the legal weekly duration fixed at 35 hours. This threshold is assessed on a calendar week basis (Monday 0:00 to Sunday 24:00), unless there is a collective agreement on adjusted working time.

For employees whose working time is organised over a period longer than a week (modulation, annualisation), overtime hours are calculated differently: they correspond to hours exceeding the annual limit of 1,607 hours (or any lower collective agreement limit that may apply).

Who is Concerned?

Only employees subject to the legal working time regulations are concerned. Excluded from the scheme are:

• Senior executives (Article L. 3111-2 of the Labour Code), who are not subject to regulations on working time.

• Employees on a day-based contract, for whom the concept of overtime hours does not apply in the same way (mechanisms for exceeding days do exist, however).

• Self-employed workers and micro-entrepreneurs.

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Applicable Salary Increase Rates

The Legal Schedule: 25% and 50%

The Labour Code (Article L. 3121-36) sets the following minimum salary increase rates:

| Overtime Hours | Legal Salary Increase Rate | |---|---| | 1st to 8th hour (H36 to H43) | + 25% | | Beyond the 8th hour (H44 and above) | + 50% |

These rates apply to the basic hourly wage, excluding bonuses and benefits in kind, unless a more favourable collective agreement provides otherwise.

Collective Agreements Can Modify These Rates

A company or sector agreement may reduce the salary increase rate to a minimum of 10% (Article L. 3121-33 of the Labour Code), which constitutes the absolute floor below which no waiver is possible. Conversely, there is nothing to prevent setting rates higher than 25% or 50% for the first brackets.

It is therefore essential to consult the applicable collective agreement for your sector before any calculation. Companies without a collective agreement are automatically subject to the legal schedule.

Replacement of Salary Increase by Compensatory Rest

Article L. 3121-33 of the Labour Code permits the replacement of all or part of the salary increase with compensatory rest for replacement (RCR). This rest must be equivalent in value to the salary increase due. For example, one overtime hour increased at 25% gives the right to 1 hour 15 minutes of rest. This mechanism is widely used to limit the impact on payroll while rewarding the employee's effort.

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Concrete Calculation of Overtime Hours

Basic Formula

The calculation of overtime remuneration follows the following formula:

Overtime Remuneration = Base Hourly Wage × (1 + salary increase rate)

Practical Example:

• Gross monthly wage: €2,500

• Reference monthly duration: 151.67 hours (35 h × 52 / 12)

• Base hourly wage: 2,500 / 151.67 = €16.48/h

• 5 overtime hours at 25%: 5 × 16.48 × 1.25 = €103

• 3 overtime hours at 50%: 3 × 16.48 × 1.50 = €74.16

The Annual Overtime Limit

Article L. 3121-30 of the Labour Code sets the legal limit at 220 hours per year per employee. A collective agreement may set a different limit (higher or lower). Beyond the limit, overtime hours remain possible but give rise to a mandatory compensatory rest (COR), the rate of which is:

• 50% in companies with 20 or fewer employees;

• 100% in companies with more than 20 employees.

Exceeding the limit also requires prior notification of the Works Council (Comité Social et Économique).

Tax and Social Exemptions: The "TEPA Law" Scheme

Since the Law of 21 August 2007 (known as the TEPA Law), reinforced by the "Purchasing Power" law of 2022, remuneration for overtime hours benefits from:

• An income tax exemption up to a limit of €7,500 per year (Article 81 quater of the General Tax Code).

• A reduction in employee social security contributions on remuneration paid for overtime hours.

• A flat-rate deduction of employer contributions for companies with fewer than 20 employees.

These tax and social advantages make overtime hours a tool for optimising net remuneration, but they require rigorous traceability of hours actually worked.

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Traceability, Compliance and Digital Tools

The Obligation to Count Working Time

The employer is legally required (Article D. 3171-8 of the Labour Code) to keep a record of the working time duration of each employee, hour by hour, day by day. This document must be kept for one year and made available to the labour inspector and the Works Council upon request.

In case of URSSAF or labour inspection control, the absence of precise counting may result in a reclassification of working time and recovery of contributions, together with penalties of up to 10% to 40% of the amount evaded.

Formalisation of Agreements: The Role of Electronic Signature

When a company agreement on overtime hours—or an individual amendment—must be concluded, the question of signature arises acutely. Using electronic signature for HR contracts makes it possible to guarantee time-stamping, document integrity and certain identification of the signatory, three essential elements in the event of employment tribunal disputes.

In this context, it is useful to understand the levels of electronic signature provided for by the eIDAS regulation: a simple electronic signature is sufficient for most HR amendments, whilst an advanced or qualified signature will be recommended for collective agreements with significant financial implications.

For SMEs seeking to structure their document process without heavy infrastructure, the complete guide to electronic signature in business provides an overview of solutions adapted to each organisation size.

Archiving and Retention Period

Payslips, time records and agreements relating to overtime hours must be kept for 5 years (prescription period for wages, Article L. 3245-1 of the Labour Code). In the event of a dispute, the burden of proof rests with the employer to show that the claimed hours were not worked—or that they were properly paid.

A system of compliant electronic signature and archiving provides an auditable trail that is difficult to contest before the court. It also reduces the time required to process working time adjustment agreements, often synonymous with administrative blockages in multi-site companies.

Finally, to assess the return on investment of such a digitalisation initiative, HR teams can use the electronic signature ROI calculator available on Certyneo.

Legal Framework Applicable to Overtime Hours

The French regulation of overtime hours is based on a dense legislative framework, articulated between the Labour Code, collective agreements and several specific laws.

Labour Code — Reference Texts:

• Article L. 3121-28: definition of overtime hours beyond the legal duration of 35 hours.

• Article L. 3121-30: legal annual limit set at 220 hours per employee.

• Article L. 3121-33: possibility of waiver by company or sector agreement, with minimum salary increase of 10%.

• Article L. 3121-36: legal salary increase rates (25% then 50%).

• Article L. 3121-37: mandatory compensatory rest beyond the limit.

• Article D. 3171-8: obligation to keep daily and weekly records of working time duration.

• Article L. 3245-1: five-year prescription period for wages.

Tax Provisions:

• Article 81 quater of the General Tax Code: income tax exemption up to €7,500 per year for overtime hours.

• Law No. 2007-1223 of 21 August 2007 (TEPA Law) and its amendments from the Law No. 2022-1158 of 16 August 2022 (purchasing power): reduction of employee contributions and flat-rate deduction of employer contributions.

Key Case Law:

• The Civil Chamber of the Court of Cassation regularly reminds (notably Cass. Soc., 18 March 2020, No. 18-10919) that if the employee produces sufficiently precise information on the number of hours claimed, it is for the employer to contradict this information by providing evidence of actual working time. The absence of counting therefore constitutes a major litigation risk.

Risks in Case of Non-Compliance:

• Salary recall plus legal interest over 5 years in case of unpaid hours.

• URSSAF adjustment with penalties (10% to 40%) if exemptions were wrongly applied.

• Offence of concealed work (Article L. 8221-5 of the Labour Code) if overtime hours are deliberately concealed, punishable by a fine of €45,000 and 3 years' imprisonment for the natural person.

• Liability for exceeding maximum working hours (10 hours/day, 48 hours/week, 44 hours on average over 12 weeks).

Documented and time-stamped management—notably through electronic signature tools compliant with eIDAS Regulation No. 910/2014—constitutes the best protection against these risks.

Usage Scenarios: Managing Overtime Hours in Business

Scenario 1 — An Industrial SME of 45 Employees During a Period of High Activity

An industrial SME specialising in automotive subcontracting must face a peak in orders over two months. The employer asks 20 production employees to carry out between 6 and 8 hours of overtime per week over 8 weeks, totalling 48 to 64 overtime hours per employee.

Before launching the campaign, the HR manager checks the remaining limit for each employee (legal limit of 220 h/year) and notes that some employees have already worked 90 hours since January. He formalises individual amendments to the organisation of working time via an electronic signature platform, which allows him to obtain validations in less than 24 hours compared to 3 to 4 days previously in paper format. Automatic time counting allows for precise calculation of 25% increases (H36-H43) and 50% increases (H44+), and integrates the amounts into the following month's payroll. Result: zero payroll errors over the campaign, processing time reduced by 70%.

Scenario 2 — An Accounting Firm of 18 Employees During the Tax Period

During the financial year-end closing period (March-April), an accounting firm mobilises its employees beyond 35 hours per week. Rather than paying a salary increase in cash—which would affect the firm's cash flow—the manager opts for compensatory rest for replacement (RCR), provided for in the company agreement.

Each overtime hour increased at 25% automatically generates 1 hour 15 minutes of rest credited to an individual counter accessible online by each employee. Formalisation of the company agreement on RCR, co-signed electronically by the staff representative and the manager, is archived with qualified time-stamping. In the event of a labour inspector audit, the firm has a complete audit trail, accessible in a few seconds. This organisation has reduced tensions relating to uncompensated hours and improved team satisfaction by 15 points on the annual internal survey.

Scenario 3 — A Group of Private Clinics Managing Complex Schedules

A group of private clinics with approximately 600 beds must manage schedules for healthcare staff subject to annual cycles of working time. Overtime hours are only counted at the end of the cycle, which complicates HR monitoring. A modulation agreement has been negotiated with trade union representatives, setting the overtime trigger threshold at 1,607 hours per year.

Thanks to a time management tool coupled with an electronic signature solution, amended scheduling amendments (cycle changes, recovery of unused leave) are signed remotely by health managers. This process has reduced approval times from 5 days to less than 4 hours, and has made it possible to automatically detect limit overruns before they generate unanticipated rest obligations. The payroll department has seen a 30% reduction in payroll errors related to overtime hours over the last 12 months.

Conclusion

The calculation of overtime hours and the application of legal salary increases allow no room for approximation: rates of 25% or 50%, a limit of 220 hours, tax exemptions conditional on impeccable traceability—each parameter has a direct impact on payroll and company compliance. Beyond mastering legal rules, it is the quality of counting, formalisation and archiving tools that makes the difference in the event of an audit or dispute.

Digitalising the management of amendments, company agreements and time records with an electronic signature solution compliant with eIDAS is transforming an administrative constraint into an operational advantage. Certyneo supports HR teams in this approach with simple, secure and auditable workflows.

👉 Discover our HR solutions on Certyneo and secure your working time agreements from today.