Short answer. For penalties other than deprivation of liberty, the Revised Penal Code counts the duration only from the day the defendant actually commences to serve the sentence — not from the date of conviction, and not from the date the judgment becomes final.
What the law says
The duration of the other penalties shall be computed only from the day on which the defendant commences to serve his sentence.
Revised Penal Code, Article 28 — Computation Of Penalties. Read the full provision →
Article 28 treats different penalties differently
Article 28 does not use a single starting point for every kind of penalty. It sets out separate rules depending on the nature of the penalty and the offender's situation: one rule for temporary penalties served by someone already in prison, another for a penalty of deprivation of liberty when the offender is not in prison, and a third, separate rule for the other penalties — the category that covers a fine or any non-custodial penalty.
Why imprisonment-based penalties count differently
For an offender already in prison, the duration of a temporary penalty is computed from the day the judgment of conviction becomes final. For an offender not in prison but subject to a penalty of deprivation of liberty, the count instead begins when the offender is placed at the disposal of the judicial authorities for enforcement of the penalty. These two rules exist because a custodial penalty's clock is tied to the offender's actual custody status, which is not automatically the same as the date of conviction or finality.
The rule for a fine or other non-custodial penalty
For everything else — the other penalties, which includes a fine and any penalty that is not deprivation of liberty — Article 28 sets a plainer rule: the duration is computed only from the day the defendant commences to serve the sentence. This means neither the date of conviction nor the date the judgment becomes final is, by itself, the starting point. What matters is the actual day performance of the sentence begins.
Why the distinction matters
Because the rule ties the count to actual commencement rather than to conviction or finality, a delay between those events and the day the sentence is actually begun does not, on its own, start the clock. If your penalty is not deprivation of liberty, the practical question becomes when service of that specific penalty actually began, since that is the date Article 28 identifies as the one that starts its duration running. This can matter considerably where enforcement of a fine or other non-custodial penalty is delayed for administrative or practical reasons, since the delay itself does not shorten or otherwise affect how the penalty's duration is eventually computed once service actually begins.