Sewing patterns are often provided in multiple paper sizes so you can print them based on your location and printing method.
A4 paper is commonly used in Europe and measures 210 × 297 mm (8.27 × 11.69 inches).
US Letter paper is standard in the United States and measures 8.5 × 11 inches (216 × 279 mm).
The size difference is small, but A4 is slightly taller and slightly narrower than US Letter. Always print the file that matches your paper size to avoid alignment issues.
Katkow tiled pages include printer margins. You will trim or fold off the margins later when assembling your pattern pages.
A0 is a large format paper size used for copy shops and plotter printers. It measures 841 × 1189 mm (33.1 × 46.8 inches). A0 patterns are printed on one or a few large sheets instead of many tiled pages.
If printing at home, use the A4 or US Letter version and assemble the pages. If using a copy shop, choose the A0 version to save time taping pages together.
Regardless of paper size, always print at 100 percent scale and check the test square before cutting.