Short answer. Not less than twenty-four consecutive hours. The Labor Code makes it the duty of every employer, whether operating for profit or not, to provide each employee a rest period of at least twenty-four consecutive hours after every six consecutive normal work days.
What the law says
It shall be the duty of every employer, whether operating for profit or not, to provide each of his employees a rest period of not less than twenty-four (24) consecutive hours after every six (6) consecutive normal work days.
Labor Code, Article 91 — Right To Weekly Rest Day. Read the full provision →
Twenty-four hours, and they must be consecutive
The wording is a rest period of not less than twenty-four (24) consecutive hours after every six (6) consecutive normal work days. Two adjectives carry the provision. Consecutive means an unbroken block, so a rest day assembled from scattered hours off across the week does not satisfy it. And not less than makes twenty-four a floor rather than the entitlement — an employer may give more, and a collective agreement or company practice frequently does. What it may not do is give less.
The obligation is on the employer and it is universal
The article frames this as a duty of every employer, whether operating for profit or not. That last phrase forecloses the argument that a non-profit, a foundation or a charitable institution stands outside the rule. It is also framed as a duty rather than as something the employee must claim, which matters: a worker who never asked for a rest day has not thereby given it up, and an employer who never scheduled one has not been excused by the silence.
Where the twenty-four hours fall is the employer's call
The same article provides that the employer shall determine and schedule the weekly rest day, subject to any collective bargaining agreement and to the rules the labour department issues. So the entitlement is to the rest, not to a particular day of the week, and a schedule that moves your rest day around is not for that reason unlawful. There is one stated exception: the employer must respect an employee's preference where it is based on religious grounds.
Count from your actual schedule
The measure is six consecutive normal work days, which is a fact about your roster rather than about the calendar week. If you are working seven straight, or if the rest day is scheduled and then cancelled often enough that a full twenty-four consecutive hours never arrives, keep your own record of days worked and hours in and out. That record, set against the roster the company keeps, is what any complaint about rest days is decided on — and it is also what establishes the premium pay owed for rest-day work.