The magazine began as a bimonthly, but switched to a monthly schedule in January 1940, though this only lasted six issues. June 1940 was followed by August and October 1940 and January and March 1941. The May 1941 issue inaugurated another monthly period that lasted until August 1943, when the schedule switched back to bimonthly until the June 1944 issue. "Fantastic" then went on a quarterly schedule, beginning with the October 1944 issue; in October 1945 it became bimonthly again, though there was a gap between February and May 1946. From September 1947 to the end of the run the magazine was monthly. The volume numeration was regular, with a new volume starting at the beginning of each calendar year; the result was a variable number of issues in each volume, from a low of four in 1944 to a full twelve when the magazine was monthly, as it was for the last few years of its life. The last issue was volume 15 number 3.