The ideal length for a sword can vary depending on factors such as the specific type of sword, its intended purpose, historical context, and individual preferences. Here are some general guidelines for sword lengths based on different types:

1. Longsword: Longswords typically have a blade length ranging from approximately 35 inches (88 cm) to 47 inches (120 cm). The total length, including the hilt, can range from around 45 inches (114 cm) to 55 inches (140 cm). Longswords are designed to be wielded with two hands, providing reach and leverage in combat.
2. One-Handed Sword: One-handed swords, such as arming swords or cut-and-thrust swords, often have a blade length between approximately 28 inches (71 cm) to 34 inches (86 cm). The total length of the sword can range from around 35 inches (89 cm) to 40 inches (102 cm). One-handed swords are typically more maneuverable and allow for the use of a shield or the off-hand in combat.
3. Rapier: Rapiers, primarily used for thrusting techniques, typically have a blade length ranging from approximately 37 inches (94 cm) to 45 inches (114 cm). The total length, including the hilt, can range from around 42 inches (107 cm) to 50 inches (127 cm). Rapiers are characterized by their long, slender blades and are associated with Renaissance-era fencing.
4. Katana: Katanas, the traditional Japanese swords, usually have a blade length ranging from approximately 25 inches (64 cm) to 30 inches (76 cm). The total length, including the hilt, can range from around 39 inches (99 cm) to 43 inches (109 cm). Katanas are designed for one-handed use and are renowned for their balance, cutting ability, and swift draw.

It's important to note that these measurements are general guidelines and can vary depending on the specific design, historical period, and cultural preferences. Factors like the wielder's physique, fighting style, and historical accuracy also play a role in determining the best sword length for an individual. Consulting with experts, experienced practitioners, or instructors in specific sword disciplines can provide valuable insights when determining the most suitable sword length for a particular purpose.