Since A-4 paper is difficult to obtain in white, let alone colors or duo, in the USA, I cut down other sizes of color or duo paper to fold A-4 based models. To do this, I multiply the longest side of the paper I want to use by .707, which is the ratio of short to long side of A-4 paper. Examples: 12-inch origami square can be cut down to 8.5" X 12", 8-inch square paper can be cut down to 5.65" X 8" (which is easier to measure in mm: 143.5mm X 203mm), 6-inch square paper cab be cut down to 4.25" X 6". I folded this adorable(!) whale with a little piece of duo measuring 2 3/8" X 3" (55mm X 76mm) and it worked perfectly.
Comments
Since A-4 paper is difficult to obtain in white, let alone colors or duo, in the USA, I cut down other sizes of color or duo paper to fold A-4 based models. To do this, I multiply the longest side of the paper I want to use by .707, which is the ratio of short to long side of A-4 paper. Examples: 12-inch origami square can be cut down to 8.5" X 12", 8-inch square paper can be cut down to 5.65" X 8" (which is easier to measure in mm: 143.5mm X 203mm), 6-inch square paper cab be cut down to 4.25" X 6". I folded this adorable(!) whale with a little piece of duo measuring 2 3/8" X 3" (55mm X 76mm) and it worked perfectly.