He was seen in apparent good health and humor as he celebrated his big day.
Philip received a 62-gun salute and the occasion was commemorated with a Royal Mint coin with his image on one side and the queen's on the other.
The royal family is planning a reception for Philip at Windsor Castle on Sunday.
Philip said due to his age, he plans to scale back his official schedule and hand over control of his various charities.
"I reckon I've done my bit. I want to enjoy myself for a bit now. With less responsibility, less rushing about, less preparation, less trying to think of something to say," he said.
Philip, also known as the Duke of Edinburgh, married the queen in 1947. He is the son of the late Prince Andrew of Greece and a great-great-grandson of Britain's Queen Victoria, giving him deep royal roots.
The Associated Press contributed to this story