If you want to count the literal time between the two tales, you need to skip ahead to the last pages of “The Hobbit.” These say that, “One autumn evening some years afterwards” Gandalf and Balin visit Bilbo. The appendices of “The Return of the King” clarify that this event happens seven years after the main story ends, in the year 2949 TA.

As far as “The Lord of the Rings” is concerned, the story technically begins with a rapid summary of Bilbo’s later years, outlining how he brings Frodo to live with him at Bag End. However, within a page, the story skips forward 12 years to 3001 TA in the lead-up to Bilbo’s 111th birthday party on September 22. After this, the story suddenly skips forward 17 years. That’s right, Frodo has the Ring for 17 years before Gandalf realizes what it is and tells him that he needs to set out on his quest.

Counting strictly from the final page of “The Hobbit” to Bilbo’s 111th birthday party, the time gap narrows to just under 52 years. In either case, the jump is significant. Aragorn, for example, is a grizzled 70-year-old veteran and Chieftain of the Dúnedain when Bilbo turns 111. When Mr. Baggins hosts his unexpected party at the beginning of “The Hobbit,” the kingly hero is around 10 years old.