Paper Size Chart | A/B/C Series Standards & Chinese Cut Sizes

What is a Paper Size Chart?

A paper size chart is an essential reference tool for designers, printers, and office professionals that catalogs standardized paper dimensions used globally. This comprehensive paper size guide compiles specifications from the internationally recognized ISO 216 standard, which defines the A, B, and C series, alongside traditional Chinese paper cut sizes based on the GB/T 788-1999 national standard. Understanding these paper dimensions is fundamental for anyone working in printing, publishing, graphic design, or document preparation. The chart serves as a one-stop resource to quickly compare paper sizes, identify appropriate formats for specific projects, and ensure compatibility across different printing systems. Whether you are selecting paper for a corporate brochure, formatting a manuscript, or preparing artwork for commercial printing, having access to accurate paper size data measured in millimeters eliminates guesswork and prevents costly formatting errors. The paper size reference table covers everything from the ubiquitous A4 office paper to specialized envelope sizes, providing practical information about common applications for each format.

Functions and Underlying Principles of Paper Sizing Standards

The fundamental principle behind international paper sizes is mathematical elegance combined with practical utility. The ISO 216 standard, adopted by most countries worldwide, is built upon a unique aspect ratio of 1:√2 (approximately 1:1.414), which possesses a remarkable property: when a sheet is cut or folded in half parallel to its shorter side, the resulting halves maintain exactly the same proportions as the original. This geometric consistency simplifies enlargement and reduction processes in photocopying and printing, as content can be scaled between sizes without distortion. The A series begins with A0, which has an area of exactly one square meter, and each subsequent size is obtained by halving the preceding size along its longest dimension. The B series provides intermediate sizes for situations where A series dimensions are unsuitable, with B0 measuring 1000×1414mm, offering a geometric mean between corresponding A sizes. The C series, defined in ISO 269, is specifically designed for envelopes, ensuring that a C4 envelope perfectly accommodates an unfolded A4 sheet, a C5 fits A5, and so forth. This interlocking system creates a complete ecosystem of paper products that work harmoniously together.

In contrast, traditional Chinese paper sizing follows a different logic based on the concept of "kai" numbers, which represent how many times a full parent sheet is divided. The standard parent sheet comes in two varieties: Zhengdu (正度) with a base size of 787×1092mm, and Dadu (大度) measuring 889×1194mm. These dimensions are rooted in historical printing press capacities and paper manufacturing traditions. The "kai" system works by successively folding or cutting the full sheet: 2-kai means the sheet is divided in half, 4-kai into four pieces, 8-kai into eight, and so forth up to 64-kai for pocket-sized publications. The theoretical cut sizes listed in this paper size chart represent the calculated dimensions before the final trimming process. In actual commercial printing, finished products are typically trimmed by 1-3mm on each edge to remove rough borders and ensure clean, precise final dimensions. This distinction between theoretical and finished sizes is crucial for print layout preparation, and the paper size guide accounts for these variations to support accurate production planning.

How to Use This Paper Size Chart

Using this paper size chart is straightforward and designed for maximum efficiency. Begin by identifying the paper series you need using the filter buttons at the top of the page, which allow you to switch between viewing all paper sizes, only A series, B series, C series, Zhengdu cut sizes, or Dadu cut sizes. The table displays essential information for each specification: the size name, exact dimensions in millimeters, and common usage scenarios that help you understand which paper format is appropriate for your specific project. For quick reference, each row includes a copy button that instantly saves the paper size data to your clipboard for use in design software or documentation. The comprehensive paper size guide is particularly valuable when you need to compare different standards, such as understanding how the commonly used A4 size (210×297mm) relates to the Dadu 16-kai theoretical size (210×298mm) or the traditional Zhengdu 16-kai (196×272mm). Designers working on international projects can quickly verify which envelope size corresponds to their chosen paper format using the C series data. The search and filter functionality enables rapid navigation through the extensive database of paper specifications, making this chart an indispensable daily tool for anyone who regularly works with printed materials.