---
title: Understand payroll preparation in Illizeo
description: "Illizeo makes payroll dependable before it goes into production: it gathers the month’s variable elements, surfaces the anomalies, freezes the period and produces a dated, versioned file. The legal calculation stays with whoever runs payroll. - **Reading time**5 min -…"
url: "https://illizeo.com/en/centre-aide/understand-the-preliminary-salaries-module/"
updated: "2026-09-23"
category: Payroll
---

# Understand payroll preparation in Illizeo

Illizeo makes payroll dependable before it goes into production: it gathers the month’s variable elements, surfaces the anomalies, freezes the period and produces a dated, versioned file. The legal calculation stays with whoever runs payroll.

- **Reading time**5 min
- **Level**Intermediate
- **Last updated**May 2026
- **Module**Preliminary salaries

## Who does what

Illizeo **prepares** payroll: it gathers, checks and freezes everything that has to reach whoever produces it. Computing contributions, issuing payslips and filing declarations stay with your accountant, your payroll team, or our experts. That split is deliberate: you gain the collection and the checking, without depending on a calculation engine that would have to track every canton and every collective agreement.

| In Illizeo | At the payroll producer |
| --- | --- |
| Base salary, bonuses, pay components | Employee and employer contributions |
| 13th, 14th, 15th month and their payment months | Withholding tax and tax tables |
| Absence prorata, rounding | The payslip |
| Advances and loans | Social declarations |
| Attendance and approved hours | Payment |

## The monthly cycle

1. ### Open the period

   Payroll is worked month by month. A summary gives the wage bill, its delta against last month, the number of alerts, absences, joiners, leavers and changes.
2. ### Go through the tabs

   Attendance, changes of the month, documents, alerts, audit log. Each tab answers one question: “what moved”, “what looks wrong”, “who touched what”.
3. ### Clear the alerts

   The module raises missing IBANs, negative leave balances and salary changes, among others. A handled alert can be dismissed, and restored if you were wrong.
4. ### Compare against the previous version

   Each generation creates a numbered version. Comparing two versions of the same month shows what changed in between — the check that catches the most mistakes.
5. ### Approve the period

   Approval freezes the month. It can be revoked if something lands late.
6. ### Generate the file

   The document produced is an XLS, CSV or PDF file, dated and versioned, downloadable. That is what goes to the payroll producer.

## The settings that change the amounts

| Setting | Effect |
| --- | --- |
| Calculation base | The monthly salary divisor: 21 fixed days, 260 annual days (Swiss practice), the 30th method, actual working days, or calendar days |
| Prorata behaviour | Deduct absence days, or ignore them |
| Rounding | Set separately for salary, bonuses and advances |
| Extra months | 13th, 14th, 15th, with their payment month(s). The 14th requires the 13th; the 15th requires both. |
| Currency | Global, or per sub-company |
| Grouping | The sheet groups by department, office, occupation type, marital status, nationality, salary type — or not at all |

## What does not exist

No gross-to-net simulator. No computation of employee or employer contributions. No employer cost computed. No withholding tax computed. No payslip produced. No side-by-side scenario comparison. No anonymised PDF to send a candidate.

## FAQ

   Does Illizeo replace a payroll system?

No, and it does not try to. It removes the manual collection of variable elements and the file ping-pong, not the legal calculation.

   Can we go back after approval?

Yes. Revocation exists precisely for the item that arrives after closing.

   Who changed what during the month?

The period’s audit tab says so, and the version comparison shows the numerical effect of those changes.

   What about hours worked?

They come up from attendance management into the dedicated tab, where they can be corrected before closing.

### Simulate a raise

Learn to model a salary scenario for annual review.

[See all Payroll articles](/en/centre-aide/?cat=payroll)

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