The new black marble stone laid into the floor simply records the birth and death dates of the monarch who ruled for 70 years and died at the age of 96: "lizabeth II 1926 - 2022."
The ledger stone also records the deaths of the Queen's parents, King George VI and Elizabeth the Queen Mother, and her husband Prince Philip, who died last year.
The stone is engraved with the star of the ancient chivalric Order of the Garter, to which the queen and the other royals belonged.
The queen's coffin was laid to rest on September 19 in the King George VI Memorial Chapel at Windsor Castle's St George's Chapel.
The interment followed her state funeral in Westminster Abbey.
Her husband Philip left instructions for his remains to be transferred from the Royal Vault beneath St George's to the memorial chapel upon his wife's death.
The queen's sister Princess Margaret's ashes are interred in the same chapel.
Elizabeth often prayed in St George's Chapel, which dates back more than 500 years.
Windsor Castle reopens to the public on Thursday and people will be able to visit St George's Chapel.