Calvin was a pupil of Kitchener Road School and Radnor Road School before attending  Canton High School for Boys in Cardiff. In 1944 he was called up and enlisted in the Royal Army Service Corps aged 17.
Before enrolling at Canton High School for Boys in Cardiff, Calvin attended both Kitchener Road School and Radnor Road School. He joined the Royal Army Service Corps in 1944 when he was 17 years old.