Q: How many popes are saints?
Read more from the papal answer man, Chris Bellitto and his new book, 101 Questions on Popes and the Papacy.

A: The church has had more than 260 popes, 81 of whom have been declared saints, which works out to a little less than a third.
Tradition says that all but one of the first 48, including Peter and ending just shy of the year 500, are saints. Another 30 popes were recognized as saints in the following centuries, concluding this period of papal saints with Gregory VII, who died in 1085.
These numbers date from a time when people were declared saints by acclamation: everyone just understood and declared publicly that a person was holy. This process is not unlike how those three popes came to be called “Great” and was essentially repeated at John Paul II’s funeral in 2005. Crowds held up signs and shouted “Santo subito!” (“A saint right away!”). As with Mother Teresa, Vatican paperwork will probably catch up with a sainted reality everyone already acknowledges.
Since canonization developed during the Middle Ages as a formal process of inquiry, examination, and declaration of sanctity under papal supervision, there have been three papal saints: Celestine V (1294, who was elected and resigned within a five-month period), Pius V (1566-1572), and Pius X (1903-1914).
–From “101 Questions on Popes and the Papacy” by Christopher M. Bellitto; published by the Paulist Press and reprinted with permission of the publisher.