The ideal size for homemade napkins largely depends on the type of event and the level of formality. However, a standard size that is widely accepted for homemade dinner napkins is typically around 20 inches by 20 inches. This size is large enough to cover a lap when folded, providing the necessary functionality during a meal and it also offers ample space for creative folding designs. For a more casual or cocktail event, smaller napkins are often used, typically around 10 inches by 10 inches. These are perfect for holding drinks or small appetizers. Remember, these sizes are just a guide and the beauty of making your own napkins is that you can customize them to fit your specific needs and preferences.