Mexico

Available schemes

Scheme	Description	Years
`ordinario`	Full employee: IMSS + ISR + Infonavit	2024, 2025, 2026
`asimilados`	Asimilados a salarios: ISR only, no social security	2025, 2026

Supported pay periods

`period.type`	Supported	Proration model
`monthly`	Yes	`native`
`biweekly`	Yes	`native`
`weekly`	No — `422 PERIOD_TYPE_NOT_SUPPORTED`	—

Applies to ordinario and asimilados. Mexico is the only native scheme: its formulas prorate from period.days themselves, scaling their own caps and floors. The ISR tariff and the subsidy are tables rather than formulas, so they are applied to the equivalent monthly base and the result is scaled back to the period. At period.days = 30 this reduces to the monthly expression, so a monthly calculation is unchanged by construction. Because each period is settled on its own days, there is no balancing rule: a 14-day and a 16-day period are not two halves of anything. They land within one cent per line of the month. weekly is rejected because a month does not contain a whole number of weeks, so four weeks cannot be made to add up to the monthly filing. See Pay periods for the full model and the cost of the naive shortcut.

Example request — biweekly

curl -X POST https://api.clevis.dev/v1/payroll/calculate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "country": "MX",
    "scheme": "ordinario",
    "year": 2026,
    "period": {
      "type": "biweekly",
      "start_date": "2026-09-01",
      "end_date": "2026-09-15",
      "days": 15
    },
    "employee": {
      "id": "emp_001",
      "daily_salary": 800.00,
      "risk_class_rate": 0.00544
    },
    "employer": { "id": "employer_001" }
  }'

The response reports period_basis.sequence: 1, periods_in_month: 2 and a monthly_equivalent you can reconcile the month against.

Ordinario

The ordinario scheme covers full-time employees under Mexican labor law (Ley Federal del Trabajo). It includes all mandatory deductions and employer contributions.

What it calculates

Employee deductions:

ISR — Progressive income tax (Impuesto Sobre la Renta) using SAT bracket tables
Subsidio al empleo — Employment subsidy that reduces ISR for lower salaries
IMSS cuota obrera — Employee social security contributions (SEM, IV, CEAV)
Infonavit credit — Housing credit deduction (if applicable)

Employer contributions:

IMSS cuota patronal — Employer social security (SEM, IV, CEAV, RT, Guarderia)
Infonavit aportacion — 5% employer housing contribution
RCV — Retiro, Cesantia y Vejez contributions

Employee inputs

Field	Type	Required	Default	Description
`daily_salary`	number	Yes	—	Salario diario
`factor_integracion`	number	No	`1.0493`	Integration factor for SDI calculation
`risk_class_rate`	number	Yes	—	Prima de Riesgo de Trabajo (IMSS, LSS Art. 73), as a fraction
`overtime_amount`	number	No	`0`	Overtime pay for the period
`sunday_bonus_days`	integer	No	`0`	Sundays worked (for prima dominical)
`grocery_voucher_amount`	number	No	`0`	Grocery vouchers (vales de despensa)
`infonavit_credit_amount`	number	No	`0`	Active Infonavit credit deduction

risk_class_rate has no default. A request for Mexico that omits it is rejected with 422 VALIDATION_ERROR on employee.risk_class_rate.

Risk class rates (Prima de Riesgo)

The rate comes from the risk class the IMSS assigns to the employer. Clevis never assigns or validates it — it receives the rate already resolved.

Class	Basis	Rate
Class I	LSS Art. 73	`0.00544`
Classes II-V	LSS Art. 73	up to `0.0758`

0 is a valid value and means the employer owes nothing here — the case for asimilados.

Optional perceptions

Enable optional perceptions using the overrides field:

{
  "employee": {
    "daily_salary": 800.00,
    "overrides": {
      "bono_puntualidad": true,
      "bono_asistencia": true
    }
  }
}

Example request

curl -X POST https://api.clevis.dev/v1/payroll/calculate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "country": "MX",
    "scheme": "ordinario",
    "year": 2025,
    "period": {
      "type": "monthly",
      "start_date": "2025-03-01",
      "end_date": "2025-03-31",
      "days": 30
    },
    "employee": {
      "id": "emp_001",
      "daily_salary": 800.00,
      "factor_integracion": 1.0493,
      "risk_class_rate": 0.00544
    },
    "employer": { "id": "employer_001" }
  }'

Key reference values

Value	2024	2025	2026
UMA (diario)	$108.57	$113.14	$116.94
SMG (diario)	$248.93	$278.80	$278.80
Tope 25 UMA (mensual)	$81,427.50	$84,855.00	$87,705.00

Asimilados

The asimilados scheme covers workers under the “asimilados a salarios” tax regime. Only ISR withholding applies. There are no IMSS contributions, Infonavit, or employer social security costs.

What it calculates

ISR — Progressive income tax using the same SAT bracket tables as ordinario
No subsidio al empleo
No IMSS, no Infonavit, no employer contributions

Employee inputs

Field	Type	Required	Description
`daily_salary`	number	Yes	Salario diario

Example request

curl -X POST https://api.clevis.dev/v1/payroll/calculate \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "country": "MX",
    "scheme": "asimilados",
    "year": 2025,
    "period": {
      "type": "monthly",
      "start_date": "2025-03-01",
      "end_date": "2025-03-31",
      "days": 30
    },
    "employee": {
      "id": "emp_001",
      "daily_salary": 1500.00
    },
    "employer": { "id": "employer_001" }
  }'

Get Started

Countries

Calculations

Payouts

Guides

Available schemes

Supported pay periods

Example request — biweekly

Ordinario

What it calculates

Employee inputs

Risk class rates (Prima de Riesgo)

Optional perceptions

Example request

Key reference values

Asimilados

What it calculates

Employee inputs

Example request

​Available schemes

​Supported pay periods

​Example request — biweekly

​Ordinario

​What it calculates

​Employee inputs

​Risk class rates (Prima de Riesgo)

​Optional perceptions

​Example request

​Key reference values

​Asimilados

​What it calculates

​Employee inputs

​Example request

Available schemes

Supported pay periods

Example request — biweekly

Ordinario

What it calculates

Employee inputs

Risk class rates (Prima de Riesgo)

Optional perceptions

Example request

Key reference values

Asimilados

What it calculates

Employee inputs

Example request