A while back I did a chart with the age of the characters in the Hobbit. Below is a similar one with the age of characters at the time of the War of the Ring.
Please note that the birth year of Samwise Gamgee is T.A. 2980 and not T.A. 2983. It was added as T.A. 2983 in the Tale of the Years in the second edition of the Lord of the Ring. This contradicted the date mentioned in the Longfather Tree of Master Samwise and a later entry to the Tale of the Years. It was changed to T.A. 2980 in the 50th Anniversary Edition.