Introduction: Understanding Taxable Income in Payroll

The taxable income is one of the most strategic elements of the payslip. It determines the base on which the employee will be taxed for income tax, and constitutes the data transmitted to the tax administration via the DSN (Déclaration Sociale Nominative). However, its construction is often misunderstood, even by experienced payroll professionals.

In 2025, several parameters influence the calculation of the taxable income: the non-deductible CSG, the CRDS, the employer’s share of complementary social protection (PSC), exempt overtime, and the 1.75% deduction on the basis of the CSG/CRDS. This comprehensive guide will walk you through mastering this essential calculation, referencing 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 the clarification of payslips. It should not be confused with the net payable before tax or the social net amount (MNS).

In practical terms, taxable income is calculated using the following formula:

Taxable Income = Gross Salary – Deductible Employee Contributions + Non-Deductible CSG (2.40%) + CRDS (0.50%) + Taxable Employer Share of PSC

It is essential to distinguish these three concepts:

Net payable before tax: this is the amount 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 the net payable because it reintegrates the non-deductible CSG and the CRDS.
Social net amount (MNS): introduced in 2023, it serves as a reference for social benefits (RSA, activity bonus). It differs from taxable income since it does not include 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, and various allowances subject to contributions. For an employee with a gross monthly salary of €3,200, this amount is the starting point.

Deductible Employee Contributions

From the gross salary, all mandatory employee contributions that are deductible from income tax are subtracted. This includes:

Health, old-age, unemployment insurance contributions;
Complementary retirement contributions (Agirc-Arrco);
The deductible CSG at a rate of 6.80%;
Employee contributions for insurance and mutual insurance (employee share).

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

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

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

In 2025, the applicable rates are:

Total CSG: 9.20%, of which 6.80% is deductible and 2.40% is non-deductible;
CRDS: 0.50%, fully non-deductible.

These contributions apply on 98.25% of the gross salary (after applying the 1.75% deduction), up to 4 annual social security ceilings (4 PASS), i.e., €185,472 in 2025. Beyond this threshold, CSG and CRDS apply to 100% of the remuneration, with no deduction.

The 1.75% Deduction on the CSG/CRDS Basis

According to the BOSS, a flat-rate deduction of 1.75% is applied to earned income for calculating the CSG and CRDS basis. This deduction represents professional expenses and 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 basis would be: €3,200 × 98.25% = €3,144.

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

In practice, if the employer covers €60 per month for mutual insurance and €25 per month for insurance, totalling €85, this amount is added 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 contribution basis within the limits set by Article L.242-1 of the French Social Security Code.

Complete Example of Calculating Taxable Income in 2025

Example Data

Let’s consider the case of a senior employee with the following elements:

Gross monthly salary: €3,200
Total 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 insurance: €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

The monthly taxable income is therefore €2,582.39.

Treatment of Exempt Overtime

Principle of Tax Exemption

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

Practically, the remuneration for exempt overtime is deducted from taxable income, which reduces the employee’s tax base.

Impact on Taxable Income Calculation

If an employee earns exempt overtime amounting to €250 in net taxable income for the month, and he/she has not yet reached the annual ceiling of €7,500, this amount will be deducted from taxable income.

Example: Continuing with our employee with a taxable income of €2,582.39. If they performed exempt overtime for €250, their taxable income becomes: 2,582.39 – 250 = €2,332.39.

The employer must maintain an annual cumulative count of exempt overtime to ensure compliance with the €7,500 ceiling. Beyond this, the remuneration for overtime becomes taxable once again.

Meal Vouchers and Taxable Income

Exempt Employer Contribution and Limits

The employer’s participation in meal vouchers is exempt from income tax within certain limits. In 2025, the employer’s share is exempt if it meets the following conditions:

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

If the employer’s contribution adheres to these limits, it does not need 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 Tax Authorities

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

Errors in calculating taxable income thus have direct consequences:

On the amount of PAS withheld monthly;
On the employee’s pre-filled income tax return;
On any URSSAF or fiscal audits.

Verification and Regularization

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

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

Specific Cases Affecting Taxable Income

The IJSS paid by the CPAM in case of illness is taxable (except for exceptions related to a prolonged illness). When the employer practices subrogation, the IJSS is included in the payslip and must appear in the taxable income.

Benefits in Kind

Benefits in kind (company vehicles, housing, meals, IT goods) are integrated into the gross salary and thus into the taxable income. Their evaluation can be either flat-rate or actual, according to the rules of the BOSS.

Employee Savings

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

Severance Pay

Severance payments are exempt from income tax within 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 included in taxable income.

Best Practices for Payroll Managers

Monthly Control Points

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

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 insurance plans;
Monitor the cumulative exempt overtime to detect breaches of the €7,500 threshold;
Compare the taxable income on the payslip with the corresponding line in DSN;
Archive payslips and supporting documents to facilitate potential audits.

Common Errors to Avoid

The main errors observed in practice are:

Failing to reintegrate the employer’s share of PSC;
Confusing deductible and non-deductible CSG;
Not respecting the €7,500 ceiling for exempt overtime;
Applying the 1.75% deduction beyond 4 PASS;
Confusing 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 the taxable income serves as the base for calculating income tax. The two amounts differ mainly in how non-deductible CSG, CRDS, and certain remuneration elements are treated. The MNS does not reintegrate the same elements as the taxable income.

Does the deductible CSG reduce taxable income?

Yes. The deductible CSG (6.80%) is subtracted from the gross salary for calculating taxable income. In contrast, the non-deductible CSG (2.40%) and the CRDS (0.50%) are not deducted and thus increase taxable income relative to net payable.

How to treat exempt overtime in the 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 total to ensure compliance with this ceiling. Beyond this, overtime becomes taxable again.

Yes. The employer’s participation in funding the mandatory mutual insurance (and insurance, if applicable) constitutes a taxable advantage. It must be reintegrated into the employee’s taxable income, even if it is exempt from certain social contributions within specified limits.

How to verify 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

How to Calculate Taxable Income on Payslips in 2025: A Comprehensive Guide