Introduction: Understanding Taxable Income in Payroll

The taxable income is one of the most strategic elements of the payslip. It determines the basis on which the employee will be taxed under income tax, and it is the data transmitted to the tax authority via the DSN (Déclaration Sociale Nominative). Yet, its construction is often misunderstood, even by seasoned payroll professionals.

In 2025, several factors influence the calculation of taxable income: the non-deductible CSG, the CRDS, the employer’s share of complementary social protection (PSC), exempt overtime, or the 1.75% deduction on the CSG/CRDS base. This complete guide will walk you step by step through mastering this essential calculation, based on references from the BOSS (Bulletin Officiel de la Sécurité Sociale) available at boss.gouv.fr.

What is Taxable Income?

Definition and Role on the Payslip

Taxable income, sometimes referred to as net fiscal, corresponds to the amount of salary income subject to income tax. It has been mandatory on the payslip since the reform for clarifying payslips. It should not be confused with net payable before tax or social net amount (MNS).

Specifically, taxable income is calculated using the following formula:

Taxable Income = Gross Salary – Deductible Employee Contributions + Non-deductible CSG (2.40%) + CRDS (0.50%) + Employer’s Share of PSC Subject to Tax

It is essential to distinguish these three concepts:

Net Payable Before Tax: This is the amount that the employee actually receives in their bank account, before the withholding tax (PAS).
Taxable Income: This is the basis for calculating income tax. It is higher than net payable because it reintegrates non-deductible CSG and CRDS.
Social Net Amount (MNS): Introduced in 2023, it serves as a reference for social benefits (RSA, activity bonus). It differs from taxable income because it does not incorporate the same adjustments.

Components of the Taxable Income Calculation

Gross Salary: Starting Point

The calculation of taxable income starts from the gross salary, which includes all remuneration elements: base salary, bonuses, benefits in kind, overtime, various allowances subject to contributions. For an employee with a gross monthly salary of €3,200, this amount serves as the starting point.

Deductible Employee Contributions

All mandatory employee contributions deductible from income tax are subtracted from gross salary. This includes:

Health, old-age, and unemployment insurance contributions;
Complementary retirement contributions (Agirc-Arrco);
Deductible CSG at a rate of 6.80%;
Employee burden of provident and mutual insurance contributions.

Note: The deductible CSG (6.80%) is indeed deducted from gross salary to obtain taxable income, but the non-deductible CSG (2.40%) and CRDS (0.50%) are not.

Non-Deductible CSG (2.40%) and CRDS (0.50%)

These two contributions, although deducted from the payslip, are not deductible from income tax. Therefore, they must be reintegrated into taxable income. Practically, they increase the employee’s taxable base.

In 2025, the applicable rates are:

Total CSG: 9.20%, with 6.80% deductible and 2.40% non-deductible;
CRDS: 0.50%, entirely non-deductible.

These contributions apply to 98.25% of the gross salary (after the application of the 1.75% deduction), within the limit of 4 annual social security ceilings (4 PASS), totaling €185,472 in 2025. Beyond this threshold, CSG and CRDS apply to 100% of the remuneration, without deduction.

The 1.75% Deduction on the CSG/CRDS Base

According to the BOSS, a flat-rate deduction of 1.75% is applied to active income for calculating the CSG and CRDS base. This deduction represents professional expenses. It applies only to the portion of remuneration that is less than or equal to 4 PASS (i.e., €185,472 annually in 2025, or €15,456 monthly).

Example: For a gross salary of €3,200, the CSG/CRDS base is: €3,200 × 98.25% = €3,144.

The employer’s contribution to financing mandatory mutual insurance and provisions constitutes a taxable advantage for the employee. Although it is not subject to social security contributions (within certain limits), it must be reintegrated into taxable income.

In practice, if the employer covers €60 per month for mutual insurance and €25 per month for provisions, totaling €85, this amount adds to the employee’s taxable income.

BOSS Reference: the employer’s share of PSC is subject to CSG/CRDS but excluded from the social security contributions base as per article L.242-1 of the French Social Security Code.

Complete Example of Taxable Income Calculation in 2025

Example Data

Let’s take the case of an executive employee with the following elements:

Monthly gross salary: €3,200
Total deductible employee contributions (excluding CSG/CRDS): €580
Deductible CSG (6.80% × 98.25% × 3,200): €213.79
Non-deductible CSG (2.40% × 98.25% × 3,200): €75.46
CRDS (0.50% × 98.25% × 3,200): €15.72
Employer’s share of mutual insurance: €60
Employer’s share of provisions: €25

Step-by-step Calculation

Step 1: Gross Salary = €3,200

Step 2: Deduction of deductible employee contributions = 3,200 – 580 – 213.79 = €2,406.21

Step 3: Reintegration of non-deductible CSG = 2,406.21 + 75.46 = €2,481.67

Step 4: Reintegration of CRDS = 2,481.67 + 15.72 = €2,497.39

Step 5: Reintegration of employer’s share of PSC = 2,497.39 + 85 = €2,582.39

Thus, the monthly taxable income is €2,582.39.

Treatment of Exempt Overtime

Principle of Tax Exemption

Since the reactivated TEPA law, overtime (and additional hours for part-time employees) benefit from an income tax exemption up to €7,500 net per year. This ceiling is considered on a calendar year basis.

Practically, the remuneration for exempt overtime is subtracted from taxable income, reducing the employee’s taxable base.

Impact on Taxable Income Calculation

If an employee works overtime with a net taxable remuneration of €250 in the month, and they have not yet reached the annual ceiling of €7,500, then this amount will be deducted from taxable income.

Example: Let’s take our employee with a taxable income of €2,582.39. If they have done exempt overtime for €250, their taxable income becomes: 2,582.39 – 250 = €2,332.39.

The employer must keep an annual cumulative record of exempt overtime to ensure compliance with the €7,500 ceiling. Beyond this limit, overtime remuneration becomes taxable again.

Meal Vouchers and Taxable Income

Exempt Employer Contribution and Limits

The employer’s contribution to meal vouchers is exempt from income tax under certain limits. In 2025, the employer’s contribution is exempt if it meets the following conditions:

It represents between 50% and 60% of the voucher’s value;
It does not exceed €7.26 per voucher (2025 limit).

If the employer’s contribution meets these limits, it does not have to be reintegrated into taxable income. However, any excess must be added to the employee’s taxable income.

The Link Between Taxable Income and DSN

Transmission to the Tax Authority

Taxable income is transmitted monthly to the tax authority via the DSN. This data allows the calculation of withholding tax (PAS). The PAS rate, personalized or neutral, applies directly to the taxable income to determine the amount of tax withheld each month.

Errors in calculating taxable income have direct consequences:

On the amount of PAS withheld monthly;
On the pre-filled income declaration of the employee;
On potential URSSAF or tax audits.

Verification and Regularization

In the event of an error detected in taxable income, the employer must proceed with a regularization in the DSN. It is advisable to systematically verify the consistency between the taxable income displayed on the payslip and that transmitted in the DSN, especially in the case of:

Salary adjustments;
Contribution regularizations;
Changes in situation (part-time work, sick leave, etc.).

Particular Cases Affecting Taxable Income

The IJSS paid by CPAM in the event of illness are taxable (unless exceptions relate to a long-term illness). When the employer practices subrogation, the IJSS are integrated into the payslip and must be included in taxable income.

Benefits in Kind

Benefits in kind (company car, housing, meals, IT equipment) are included in gross salary and thus in taxable income. Their evaluation may be flat-rate or based on actual costs, according to BOSS rules.

Employee Savings

Amounts paid as part of profit-sharing or participation are not taxable if they are allocated to a savings plan (PEE, collective PER). However, if the employee opts for immediate payment, these amounts are added to taxable income.

Termination Indemnities

Severance pay is exempt from income tax under certain limits (the higher of the legal or contractual indemnity, 50% of the total indemnity, or 2 PASS). Beyond this, the excess portion is taxable and integrated into taxable income.

Best Practices for Payroll Managers

Monthly Control Points

To ensure the accuracy of taxable income, it is recommended to implement the following checks:

Verify the calculation formula in the payroll software, especially after parameter updates;
Check the reintegration of the employer’s share of PSC, particularly during changes in mutual or provision systems;
Track the cumulative exempt overtime to detect crossing the €7,500 threshold;
Compare the taxable income on the payslip with the corresponding item in the DSN;
Archive payslips and justifications to simplify potential audits.

Common Errors to Avoid

The main errors observed in practice are:

Failing to reintegrate the employer’s share of PSC;
Confusion between deductible and non-deductible CSG;
Non-compliance with the €7,500 ceiling for exempt overtime;
Applying the 1.75% deduction beyond 4 PASS;
Confusion between taxable income and social net amount.

FAQ: Taxable Income in Payroll

The social net amount (MNS) serves as a reference for social benefits (RSA, activity bonus), while taxable income serves as the basis for calculating income tax. The two amounts differ mainly due to the treatment of non-deductible CSG, CRDS, and certain remuneration elements. The MNS does not reintegrate the same elements as taxable income.

Does the deductible CSG reduce taxable income?

Yes. The deductible CSG (6.80%) is subtracted from gross salary for the calculation of taxable income. However, the non-deductible CSG (2.40%) and the CRDS (0.50%) are not deducted and thus increase taxable income compared to net pay.

How are exempt overtime treated in taxable income?

The net remuneration for exempt overtime is deducted from taxable income within the limit of €7,500 net per year. The employer must maintain an annual cumulative record to ensure compliance with this ceiling. Beyond this limit, overtime remuneration becomes taxable again.

Yes. The employer’s contribution to financing the mandatory mutual insurance (and insurance provisions, if applicable) constitutes a taxable advantage. It must be reintegrated into the employee’s taxable income, even if exempt from social contributions within certain limits.

How can I verify the taxable income on the payslip?

You can reconstruct the taxable income starting from the gross salary, deducting the deductible employee contributions (including the deductible CSG), then adding the non-deductible CSG, the CRDS, and the employer’s share of the PSC. Compare the result with the line

Calculating Taxable Income on Payslips in 2025: A Complete Guide for Employers