C Paper Standard Size Lookup

Tool Introduction

The "C Paper Standard Size Lookup" is a professional online tool designed to help users quickly and accurately query the international standard sizes of C series paper (primarily used for envelopes). This tool provides a detailed C series size comparison chart, covering all specifications from C0 to C10, and lists their precise dimensions in both common units: millimeters (width × height) and inches (width × height). In addition, the tool is equipped with an intuitive C series envelope size comparison chart, allowing users to clearly understand the relative size relationships between different specifications. C series sizes are part of the International Organization for Standardization (ISO) 269 standard, typically used for making envelopes, folders, etc., to perfectly fit ISO 216 standard A series paper.

How to Use

1. **Browse the Size Comparison Chart:** After opening this tool page, you will directly see the "C Series Envelope Size Comparison Chart." This table details the specifications for all C series sizes from C0 to C10.
2. **Consult Millimeter and Inch Data:** Each row in the table provides detailed data for the corresponding size name (e.g., C4), millimeter units (width × height), and inch units (width × height). You can consult any C series size as needed.
3. **Refer to the Size Comparison Chart:** Below the table, a "C Series Envelope Size Comparison Chart" is provided. This illustration is intended to help you more intuitively understand the visual size differences between different C series sizes. Please note that the illustrated scale is for reference only; actual precise dimensions should always be based on the data in the table.

Usage Example

Suppose you need to query the standard size of a C4 envelope:

• **Operation Demonstration:** Visit this tool page and directly locate the row labeled "C4" in the "C Series Envelope Size Comparison Chart."
• **Expected Output Result:**
  • **Size:** C4
  • **Millimeters (W×H):** 229×324
  • **Inches (W×H):** 9.0×12.8
• Through this simple and direct method, you can quickly obtain the precise standard size of any C series paper (envelope).

Frequently Asked Questions

• Q: What is C series paper primarily used for? A: C series paper sizes are mainly used for envelopes, folders, and other packaging and storage media. They are designed to perfectly accommodate the corresponding A series paper sizes. For example, a C4 envelope is specifically designed to hold an unfolded A4 paper.
• Q: What units of measurement are provided for C series sizes? A: This tool provides internationally common millimeter (mm) and inch (inch) units for size comparison, making it convenient for users from different countries and regions to consult.
• Q: Why are C series envelope sizes slightly larger than A series paper sizes? A: C series sizes are calculated based on the geometric mean of A series and B series sizes. For example, $C_n = \sqrt{A_n imes B_n}$. This design ensures that A series paper can easily fit into the corresponding C series envelope with appropriate clearance for insertion and removal.
• Q: Is the C series size an international universal standard? A: Yes, C series sizes are part of the International Organization for Standardization (ISO) 269 standard, and together with ISO 216 (A series and B series paper standards), they form a globally widely accepted paper size system.

Notes

• The C series size data provided by this tool strictly adheres to international ISO standards, and the millimeter and inch values in the table are precise standard dimensions.
• The C series envelope size comparison chart displayed on the page is for visual aid and understanding relative sizes only; its proportions may not be entirely accurate. Always refer to the values provided in the table for final and actual dimensions.
• All dimensions are labeled according to the convention of "width × height."

Uses and Characteristics of C Series Paper

The C series paper standard (ISO 269) was specifically developed by the International Organization for Standardization for envelopes, folders, and other packaging purposes, complementing the well-known A series paper standard (ISO 216). The core characteristics and wide uses of C series sizes are reflected in the following aspects:

• **Perfect Fit for A Series Paper:** The design philosophy of C series sizes is to be slightly larger than the A series paper of the same number, ensuring that A series paper can be conveniently inserted into C series envelopes. For example, an A4 sheet can easily fit into a C4 envelope, while a folded A4 sheet (i.e., A5 size) can fit into a C5 envelope. This makes the C series an ideal choice for mailing documents, sending invitations, and storing materials.
• **International Universality:** As part of the ISO standard system, C series sizes are widely recognized and used globally, which greatly facilitates international document exchange, mailing, and the printing industry.
• **Size Calculation Principle:** The width and height of C series sizes are the geometric mean of the corresponding A series and B series sizes. For example, the dimensions of C4 are the geometric mean of A4 and B4 sizes. This mathematical relationship ensures the logical consistency and practicality of the entire paper size system.
• **Common Application Scenarios:**
  • **C4 (229×324 mm):** Most commonly used, suitable for mailing unfolded standard A4 documents, contracts, or brochures.
  • **C5 (162×229 mm):** Suitable for mailing folded A4 documents or unfolded A5 booklets.
  • **C6 (114×162 mm):** Suitable for mailing folded A5 documents or cards.
  • Other sizes such as C0, C1, etc., are often used for making large poster tubes, blueprint bags, or special-sized packaging.