Introduction: Understanding Taxable Income in Payroll

The taxable income is one of the most strategic components of the payslip. It determines the basis on which the employee will be taxed under income tax, and constitutes the data submitted to the tax authorities 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 taxable income: the non-deductible CSG, the CRDS, the employer’s share of complementary social protection (PSC), the exempt overtime hours, or the 1.75% allowance on the CSG/CRDS base. This comprehensive guide will walk you through this essential calculation step by step, 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 fiscal net, corresponds to the amount of salary income subject to income tax. It has been mandatory on payslips since the reform aimed at clarifying payslip content. It should not be confused with the net payable before tax or the net social amount (MNS).

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

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

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 withholding tax (PAS).
Taxable Income: This is the basis for calculating income tax. It is higher than the net payable because it re-includes the non-deductible CSG and CRDS.
Net Social 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

The Gross Salary: Starting Point

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

Deductible Employee Contributions

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

Health, retirement, and unemployment insurance contributions;
Additional retirement contributions (Agirc-Arrco);
The deductible CSG at a rate of 6.80%;
Employee contributions to welfare and health insurance (employee share).

Note: The deductible CSG (6.80%) is indeed deducted from the gross amount to obtain the 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 on the payslip, are not deductible from income tax. They must therefore be reintegrated into the taxable income. In practical terms, 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%, which is entirely non-deductible.

These contributions apply to 98.25% of the gross salary (after applying the 1.75% allowance), capped at 4 annual social security ceilings (4 PASS), which amount to €185,472 in 2025. Beyond this threshold, CSG and CRDS apply to 100% of the remuneration, without allowance.

The 1.75% Allowance on the CSG/CRDS Base

According to the BOSS, a flat-rate allowance of 1.75% is applied to income from employment for calculating the CSG and CRDS base. This allowance accounts for professional expenses. It applies only to the portion of remuneration that is €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 the financing of mandatory health insurance and welfare constitutes a taxable benefit 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 health insurance and €25 per month for welfare, amounting to €85 in total, this amount is added to the employee’s taxable income.

BOSS Reference: the employer’s share of the PSC is subject to CSG/CRDS but excluded from the social security contribution base within the limits set by 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 a managerial employee with the following elements:

Monthly gross 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 health insurance contribution: €60
Employer’s welfare contribution: €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: Re-integration of non-deductible CSG = €2,406.21 + €75.46 = €2,481.67

Step 4: Re-integration of CRDS = €2,481.67 + €15.72 = €2,497.39

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

The monthly taxable income is therefore €2,582.39.

The Treatment of Exempt Overtime

The Principle of Tax Exemption

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

In practical terms, the remuneration for exempt overtime is removed from the taxable income, reducing the employee’s tax base.

Impact on Taxable Income Calculation

If an employee performs exempt overtime whose net taxable remuneration represents €250 in the month, and they have not yet reached the annual limit of €7,500, then this amount will be deducted from the taxable income.

Example: Let’s take our employee with a taxable income of €2,582.39. If they have performed exempt overtime worth €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, overtime remuneration becomes taxable again.

Restaurant Vouchers and Taxable Income

Employer’s Exempt Contribution and Limits

The employer’s contribution towards restaurant 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 complies with these limits, it does not have to be reintegrated into the 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 Authorities

The taxable income is transmitted monthly to the tax authorities via the DSN. It is this data that allows for the calculation of the withholding tax (PAS). The PAS rate, whether personalised or neutral, is applied directly to the taxable income to determine the amount of tax withheld each month.

Errors in the calculation of taxable income therefore have direct consequences:

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

Verification and Adjustment

In case of detected errors in the taxable income, the employer must proceed with a correction 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 cases of:

Salary catches up;
Contributions adjustments;
Changes in situation (part-time, sick leave, etc.).

Specific Cases Affecting Taxable Income

The IJSS paid by the CPAM in case of illness are taxable (except for exceptions related to a long-term illness). When the employer applies subrogation, the IJSS are integrated into the payslip and must be included in the taxable income.

Benefits in Kind

Benefits in kind (company car, accommodation, meals, IT equipment) are included in the gross salary and thus in the taxable income. Their evaluation can be either flat-rate or actual, depending on the rules from the BOSS.

Employee Savings

Amounts received for 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 the taxable income.

Severance Pay

Severance payments are exempt from income tax within certain limits (the higher of the legal or contractual severance payment, 50% of the total severance payment, or 2 PASS). Beyond this, the excess amount is taxable and included in the 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 configuration updates;
Check the reintegration of the employer’s PSC share, particularly when changing health insurance or welfare;
Track the cumulative exempt overtime to detect exceeding the €7,500 threshold;
Cross-check the taxable income on the payslip with the corresponding item in the DSN;
Archive payslips and supporting documents to facilitate potential audits.

Common Errors to Avoid

The main errors observed in practice are:

Forgetting to reintegrate the employer’s PSC share;
Confusing deductible and non-deductible CSG;
Failing to respect the €7,500 ceiling for exempt overtime;
Applying the 1.75% allowance beyond 4 PASS;
Confusing taxable income and net social amount.

FAQ: Taxable Income in Payroll

The net social 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 components as taxable income.

Does deductible CSG reduce taxable income?

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

How to treat exempt overtime in taxable income?

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

Yes. The employer’s contribution towards mandatory health insurance (and welfare, if applicable) constitutes a taxable benefit. It must be reintegrated into the employee’s taxable income, even if it is exempt from social contributions within certain limits.

How to verify taxable income on the payslip?

You can reconstruct the taxable income by starting from the gross salary, deducting the deductible employee contributions (including deductible CSG), then adding the non-deductible CSG, the CRDS, and the employer’s PSC share. Compare the result with the line for “taxable income” or “cumulative taxable income” on the payslip. In case of discrepancy, check the treatment of exempt overtime and benefits in kind.

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