Short answer. They take the vacant share in the same proportion they inherit. Article 1019 of the Civil Code is direct: the heirs to whom the portion goes by the right of accretion take it in the same proportion that they inherit. No new calculation is needed — the existing shares simply expand proportionately.
What the law says
The heirs to whom the portion goes by the right of accretion take it in the same proportion that they inherit.
Civil Code, Article 1019 — Proportion of Accretion. Read the full provision →
The rule: proportionate, not equal
Article 1019 answers the proportion question with a single, clear sentence: the heirs to whom the portion goes by the right of accretion take it in the same proportion that they inherit. The rule does not divide the vacant share equally among the remaining heirs regardless of how large or small each heir's own share already is. Instead, it tracks the existing proportions. If one heir holds twice the share of another, that heir also receives twice as much of the accreted portion. The vacant share simply distributes itself across the remaining heirs in the same ratios the inheritance already reflects.
Why proportionality, not equality
The proportionate approach follows logically from the purpose of accretion — to carry out the testator's disposition as closely as possible when one beneficiary cannot or will not take. The testator chose to give heir A a larger share than heir B for reasons that presumably still hold. If accretion instead divided the vacant share equally, it would silently override the testator's deliberate allocation. By distributing the vacant portion proportionately, Article 1019 preserves the testator's intended ratio while still filling the gap left by the absent heir.
A simple example
Suppose a will calls for three heirs to receive 50%, 30%, and 20% of an estate, and the 20% heir cannot take his share. The remaining two heirs — the 50% and the 30% — absorb that 20% in the proportion they already hold relative to each other: 50 to 30, or 5 to 3. Of the 20% that accretes, the first heir gets 12.5% and the second gets 7.5%. The estate is then divided 62.5% to 37.5% between them, keeping the original 5:3 ratio intact.
How this works in intestate succession
In intestate succession, the proportions are set by law rather than by a will. Article 1018 says the repudiated share accrues to the co-heirs; Article 1019 tells you how. Legal shares under intestate succession may already differ — a surviving spouse and multiple children do not always take in equal amounts. When one intestate heir repudiates, the accreted share distributes among the remaining heirs in their already-established intestate proportions. This is worth computing carefully in an estate settlement, especially when the estate includes real property that must eventually be titled correctly.