Odoo payroll software

Salary rules, brick by brick

A payroll, in Odoo, is a structure — one per category of staff: executive, non-executive, contractor. Each structure carries rules, and each rule is a small named calculation: a code (SALBASE, IPRES_CADRE, TRIMF), a category, a sequence, and a Python formula evaluated against the contract and the month's inputs.

Three things matter, and are awkward to fix afterwards:

• The sequence. A rule can only read what has already been computed. Income tax needs the taxable net, which needs the IPRES deductions, which need the gross. A sequence in the wrong order raises no error: it simply yields zero.
• The condition. A rule that applies only to executives, only above a ceiling, or only one month in twelve, carries that condition in the rule — not in the payroll officer's head.
• Whether it shows on the payslip. Many rules are intermediate steps and have no business on the paper handed to the employee.

We maintain these rules for twenty-nine collective agreements, with their grids, categories and working hours. When a finance act changes a rate or a ceiling, the rule changes once, for every client.

The sursalaire, and why it is computed backwards

In Senegal, what is negotiated is a net. The employee wants to know what they take home; the collective agreement, for its part, sets a minimum base salary per category. The gap between the two is the sursalaire, and it is the unknown.

The net depends on the sursalaire along a path you cannot reverse by hand: the sursalaire raises the gross, hence the IPRES, hence the taxable net, hence the tax by bracket and by household share, hence the net. Working it out by hand means guessing.

Our solver does the opposite: give it the negotiated net and it finds the sursalaire that lands exactly on it, by successive approximation — five iterations are enough, to within a franc. That is what lets you answer “that net will cost you this much” during the interview, rather than the next day.

Compute a bonus — freeagreed net → bonus, income tax, TRIMF, IPRES, CSS, employer cost

Payslip batches

Payslips are not computed one by one. A batch groups a month, a company, a set of employees: you generate, check, correct, validate, and only then post to the accounts. While the batch is a draft, everything recomputes.

The check that matters before validating is to compare the batch with the previous month, line by line. An unexplained variance on a line is almost always a badly entered input for the month, not a broken rule.

The month's adjustments

A payroll month is never a plain repeat of the last one: absences, overtime, exceptional bonuses, deductions. Those values come in as the month's inputs, entered per payslip or imported, and the rules use them.

One trap we met and fixed: some allowances are entered before the absence proration, others after. A travel allowance entered in the wrong place is prorated twice, or not at all. Our agreements tell the two families apart explicitly.

Advances and loans

Two different mechanisms, often confused:

• A salary advance is repaid within the same month or the next: a single deduction, no schedule.
• A loan is spread out: a principal, a number of instalments, a monthly deduction that stops by itself at the last one. The balance outstanding must be readable at any moment — it is the employee's first question, and the auditor's.

In both cases the deduction comes after the taxable net: you do not repay a loan with tax.

Tailoring the payslip

The payslip handed to the employee is both a legal document and a company document. We compose it from templates: the dense Senegalese model — employee and employer shares facing each other on every line, a cumulative band, a boxed net to pay — or a plainer layout. Header, logo, legal wording, columns shown: all of it is set without touching the calculation.

The rule we hold ourselves to: whatever is on the payslip must be demonstrable. Every line points to a rule, every rule to a text.

Posting to the accounts

Validating a batch means writing to the accounts. Each rule carries its debit and credit accounts, and the entry is generated company by company.

This is the step where mistakes are expensive, and we have corrected real ones: a net credited twice because two rules carried the same account; rule accounts defined globally when they differ from one company to the next within a group. The check is simple and final: total staff credits must equal the batch's net to pay, and the expense must equal the gross plus employer contributions.

Analytic accounting

Payroll is often a company's largest cost, and the one least often spread. Yet the question “how much does this site, this shop, this department cost me?” only has an answer if payroll takes part.

Every payroll journal line can carry an analytic distribution — by company, by site, by project, with percentage keys. That is what lets you read, in the same dashboard, a point of sale's margin with staff costs included.