What is the standard playing card size? The most common answer is poker size: 2.5 × 3.5 inches, or 63.5 × 88.9 mm. But choosing custom playing-card dimensions involves more than following a familiar format. This expert guide compares poker and bridge card sizes, explains print-ready artwork requirements, bleed and safe-area planning, materials, finishes, packaging fit, and manufacturing quality control. Use it to select the right format for branded decks, games, promotions, tarot cards, and educational products.