'A' size -- size in millimeters -- approx inches
2A0 -- 1,189 x 1,682 mm -- 46.8 x 66.2 in
A0  -- 841 x 1,189 mm -- 33.1 x 46.8 in
A1  -- 594 x 841 mm -- 23.4 x 33.1 in
A2  -- 420 x 594 mm -- 16.5 x 23.4 in
A3+ -- 329 x 483 mm -- 13.0 x 19.0 in
A3  -- 297 x 420 mm -- 11.7 x 16.5 in
A4  -- 210 x 297 mm -- 8.3 x 11.7 in
A5  -- 148 x 210 mm -- 5.8 x 8.3 in
A6  -- 105 x 148 mm -- 4.1 x 5.8 in
A7  --  74 x 105 mm -- 2.9 x 4.1 in