The length of a tachi handle can vary depending on the specific sword and the preferences of the swordsmith or owner. However, generally speaking, the handle of a tachi is typically longer compared to the handle of a katana.

The average length of a tachi handle is around 30 to 35 centimeters (12 to 14 inches). This longer handle allowed for a two-handed grip, which was beneficial for samurai warriors on horseback. The extra length provided better control and leverage when wielding the sword while mounted.

It's important to note that these measurements are approximate and can vary based on the individual sword and historical period. The actual length of a tachi handle can be influenced by factors such as the size of the blade, the preferences of the owner, and the intended use of the sword.