The Ōdachi, also known as nodachi, is a Japanese sword characterized by its long blade. While the exact measurements of an Ōdachi can vary, they typically have a blade length of around 90 centimeters (35 inches) or longer.

When it comes to converting this length into feet, 90 centimeters is approximately 2.95 feet. Therefore, the average Ōdachi blade length falls between 2.95 to 3.28 feet (35 to 39.37 inches).

It's important to note that the Ōdachi's length can vary depending on the specific sword and historical period. Some Ōdachi blades could reach extreme lengths of over 4 feet (48 inches), but those were exceptional cases. The length of an Ōdachi was often tailored to the wielder's height and the intended use of the weapon.