When I ask an SME owner how much they pay for overtime, I get a version of the same thing: "I give the kid a little bonus on Fridays and we call it even." That math stops working the day the workweek cap drops from 48 to 40 hours. The 41st hour is no longer ordinary, it is extraordinary, and the LFT (Federal Labor Law) did not leave it to the employer's discretion. It goes at double for the first nine and at triple from the tenth onwards. Here is the calculation, the hourly table, the case of an event shop in Cancún, and why that Saturday envelope can end up costing you more than paying correctly.