The compulsory portion of an heir is determined as follows:
(1) For a lineal descendant by blood, the compulsory portion is one half of his entitled portion;
(2) For a parent, the compulsory portion is one half of his entitled portion;
(3) For a spouse, the compulsory portion is one half of his entitled portion;
(4) For a brother or a sister, the compulsory portion is one-third of his or her entitled portion;
(5) For a grandparent, the compulsory portion is one-third of his entitled portion.

A compulsory portion is determined by deducting the amount of debts from the property of the succession as reckoned according to Article 1173.

A person entitled to a compulsory portion may have the amount of the deficit deducted from the property of a legacy, if the amount of his compulsory portion becomes deficient on account of the legacy made by the testator. If there are several legatees, deductions must be made in proportion to the value of the legacies they severally receive.