PA4

With dimensions of 210mm x 280mm, the PA4 format has a total surface area of 0.0588 square meters. Part of the transitional PA paper size series proposed in 1975, PA4 directly bridges the gap between PA3 and the popular A4 standard from ISO 216. Notably, PA4 shares the same width as A4 but gains additional vertical space with its taller height. This makes PA4, alongside its landscape cousin PA5, one of the more commonly used PA sizes. PA4 boasts a few alternative names including L4 and Extra A4, highlighting its versatility as a version of A4 extended along one side. Typical applications include magazines, international periodicals, catalogs, and binding where the extra height allows more room for multipage content in a familiar A4-like form factor. Despite rejection during standardization, PA4 fills an important void between PA3 and A4 for vertical applications, demonstrated by its sustained popularity across diverse global publications. Its backing as a transitional PA format might lack extensive history, but PA4 non-standard size continues earning its place facilitating vertical A4 use cases requiring just slightly more space than the standard size provides.