Hi,
Did you know that the Secretaria de Trabajo has their own website? I'm not sure what it is, but it shouldn't be too hard to find...From that site you can print out the form to do the calculation of what is owed to the employee.
If you are terminating their employment immediately, you must pay them 2 weeks salary as "pre-aviso" and cesantia (special calculation). There are many ways to avoid paying these, depending on the reason that the person is being dismissed. I'm sure you could call the Secretaria for more information.
Then, everyone is entitled to the regalia navidena, which is one full month's salary for a full year's work. If, for example, only 8 months have been worked, then the amount is divided by 12 months and multiplied by 8. Finally, the employee is entitled to 14 days paid vacation per year. You should divide their monthly salary by 23.83 to establish their daily wage and multiply by 14 for a full year's work. If the employee has worked, for example, 6 months of the year, then you would divided 14 days by 6, and multiply the result by their daily wage to calculate.
Hope this helps,
Jill