Short answer. Both ask the same trial court to undo a conviction before it becomes final, but they attack different problems. Reconsideration only points to errors of law or fact already sitting in the judgment and needs no further proceedings. A new trial goes further, reopening the case itself over trial irregularities or evidence that surfaces afterward.
What the law says
At any time before a judgment of conviction becomes final, the court may, on motion of the accused or at its own instance but with the consent of the accused, grant a new trial or reconsideration.
Rule 121, Section 1 — New trial or reconsideration. Read the full provision →
What the law says
The court shall grant reconsideration on the ground of errors of law or fact in the judgment, which requires no further proceedings.
Rule 121, Section 3 — Ground for reconsideration. Read the full provision →
What the two motions share
Both remedies exist for the same window: any time before the judgment of conviction becomes final. Either one may be brought on the accused's own motion, and either one can also be initiated by the court itself — but only with the accused's consent, since the court cannot force a reopening or a review of its own judgment on someone who does not want it. Filing one does not automatically rule out the other; an accused can raise both together where the facts support it, asking the court to reconsider some points and retry others.
When reconsideration is the right tool
Reconsideration is the narrower and faster remedy. The court grants it on the ground of errors of law or fact in the judgment, and — critically — it requires no further proceedings. That means the court works from what is already in the record: it re-examines its own reasoning, corrects a misapplied rule, or fixes a mistaken reading of the evidence already presented, and issues a corrected judgment. Nothing new is heard. This is the remedy for a conviction that got the facts or the law wrong based on what was already before the court.
When a new trial is the right tool
A new trial is the heavier remedy, and it is used for problems reconsideration cannot fix because they are not visible from the judgment alone. Typical grounds involve something wrong with how the trial itself unfolded — irregularities that affected the accused's rights during the proceedings — or evidence that was not available at the time of trial and could not reasonably have been presented then. Because these grounds require the court to look beyond the existing record, granting a new trial can mean reopening proceedings rather than simply correcting a judgment on paper.
Choosing between them
The practical difference comes down to what actually went wrong. If the judgment misapplied the law or misread evidence already on record, reconsideration is the direct, faster route, since it produces a corrected judgment without more proceedings. If the problem is with the trial process itself, or new evidence has come to light since, reconsideration cannot reach it — that calls for a new trial instead. Getting the choice wrong wastes the narrow window before the conviction becomes final, so identifying which kind of defect is actually present matters as much as filing quickly.