How long did the 100 Years War actually last?

The Hundred Years’ War actually lasted 116 years. The series of intermittent conflicts between France and England that took place during the 14th and 15th centuries wasn’t classified as the “Hundred Years’ War” until 1823. Traditionally, the war is said to have begun in 1337 when Philip VI attempted to reclaim Guyenne (part of the region of Aquitaine in southwestern France) from King Edward III—who responded by laying claim to the French throne—and to have lasted until 1453 when the French claimed victory over the disputed territory at the Battle of Castillon.

Source: History