Short answer. Eighteen. Under Philippine law, majority — being a legal adult — commences at the age of eighteen years, and emancipation takes place upon reaching majority. Before RA 6809, the age was twenty-one; the law now fixes eighteen as the point at which a person is treated as an adult, unless another law provides otherwise.
What the law says
Emancipation takes place by the attainment of majority. Unless otherwise provided, majority commences at the age of eighteen years.
RA 6809, Section 1 — Majority At Eighteen. Read the full provision →
Majority begins at eighteen
The rule, as amended by RA 6809, is stated in one line: "Emancipation takes place by the attainment of majority. Unless otherwise provided, majority commences at the age of eighteen years." So eighteen is the age at which the law regards a person as an adult. Reaching it brings emancipation — the end of the parental authority a person was under as a minor. This lowered the old threshold; for a long time a Filipino did not become a legal adult until twenty-one. Since this amendment, the answer for general purposes has been eighteen.
What emancipation actually changes
Becoming a legal adult is not merely symbolic. On reaching majority a person is generally treated as having full civil capacity: they may enter into contracts, sue and be sued, and manage their own person and property without needing a parent's consent or a guardian to act for them. The parental authority that governed them as a minor — over both their person and, in the ordinary case, their property — comes to an end. In short, the law stops treating them as someone who must act through others and starts treating them as responsible for their own affairs.
"Unless otherwise provided"
The qualifier matters. Turning eighteen makes a person a legal adult for general purposes, but particular activities carry their own minimum ages set by other laws. The age required to marry, the age of criminal responsibility, and the ages tied to specific transactions or licences are governed by their own statutes, and reaching majority does not automatically satisfy every one of them. So it is more accurate to say eighteen is the default age of adulthood than to treat it as a single key that unlocks everything at once. Where a specific right or act is in question, the law on that subject controls.
Why the age matters in practice
The practical weight of turning eighteen is that a person no longer needs parental consent for most civil acts and now bears full legal responsibility for their own decisions. That cuts both ways: the freedom to contract and act independently comes with accountability for the obligations that result. Reaching majority also does not instantly extinguish every relationship formed in minority — for instance, entitlements such as support can continue in circumstances the law recognises. This is general information about the age of majority, not advice on any particular right or transaction.